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Production two-tower improvement gemini-3-8-flash-high-08

The full recorded conversation, expanded from start to finish: instructions, agent messages, and tool inputs and responses.

This recording includes 185 readable reasoning summaries, shown in full below.

Agent
gemini-3.8-flash · Gemini CLI · high effort
Recorded conversation
59:26 · 86 steps
Private reward
0.009092 · Failed
Attempt cost
$1.48
  • Thinking
  • Model text
  • Tool call
  • Tool response
01

User context

+00:00
User context

<session_context> This is the Gemini CLI. We are setting up the context for our chat. Today's date is Tuesday, September 29, 2026 (formatted according to the user's locale). My operating system is: linux The project's temporary directory is: /home/agent/.gemini/tmp/app

  • Workspace Directories:
  • /app
  • Directory Structure:

Showing up to 200 items (files + folders).

/app/ └───solution/

</session_context>

02

Task instructions

+00:00
Task instructions

Improve a production music-discovery two-tower

You have joined the recommendations team for a music streaming service. The "Made for You" shelf is served by a mature production two-tower model. Its chronological data protocol and indexed serving path are sound, but its offline retrieval quality no longer clears the team's next launch gate.

Your job is to investigate the production model, improve its retrieval quality, and ship a better ranking artifact. Use the implementation and public validation data to form and test your own diagnosis.

The source used to reproduce the production model is included under /task/current_model/. You may copy it into /app/solution/, edit it, add tests, and improve its training objective, but keep the data protocol, two-tower serving contract, and evaluation boundary intact.

Production Context

The model must satisfy a strict request-time latency budget. Item vectors are precomputed offline. At request time, one user vector is computed from observed interaction history and compared with candidate item vectors by a batchable two-tower score. Do not introduce a cross-encoder, per-candidate sequence model, or user-ID lookup table.

The current trainer is a mature baseline with chronological internal validation. Focus your investigation on how its training objective selects and uses negative examples. Diagnose limitations in the current negative-sampling strategy and improve it under the fixed CPU budget. Validate changes with the public backtest. The final approach must still train and rank within the supplied CPU environment while preserving the serving and data boundaries above.

What You Have

All public inputs are under /task/data/. A stage cutoff is the timestamp at which observed history and candidate eligibility are frozen for a ranking. The public validation stage cutoff is 24786800, when train_* ends. A 30-minute gap precedes the seven-day val_* window. For the final submission, that validation window becomes observed history, and another 30-minute gap precedes the hidden seven-day outcome window.

The package includes:

  • /task/current_model/train_current_model.py: the production training and ranking script. It can reproduce the public validation ranking and produce a hidden-test submission after refitting.
  • /task/current_model/two_tower_model.py: model primitives used by the production script.
  • /task/evaluate_public.py: the public validation evaluator for development.
  • /task/data/validation_eligible_candidates.npz and /task/data/test_eligible_candidates.npz: platform-owned candidate sets for the validation and hidden-test cutoffs.
  • /task/data/validation_preference_state.parquet and /task/data/test_preference_state.parquet: active explicit preference state at the corresponding cutoffs.
  • /task/requirements.txt: the exact offline Python distribution inventory.

You can reproduce the production public backtest with:

python /task/current_model/train_current_model.py \
  --stage validation \
  --public-dir /task \
  --output /app/solution/production_validation.parquet
python /task/evaluate_public.py /app/solution/production_validation.parquet

Data

For each event family there is a train_*.parquet and val_*.parquet file:

FamilyMeaningColumns
listensPlayback eventsuid, timestamp, item_id, is_organic, played_ratio_pct, track_length_seconds
likesExplicit positive actionsuid, timestamp, item_id, is_organic
dislikesExplicit negative actionsuid, timestamp, item_id, is_organic
unlikesReversal of a prior likeuid, timestamp, item_id, is_organic
undislikesReversal of a prior dislikeuid, timestamp, item_id, is_organic

is_organic=1 means the listener sought out the track; 0 means the action came through a recommendation surface. A listen is a conventional positive at 50% completion. The discovery-quality objective below uses the stronger 80% threshold.

The two public windows have different roles:

  1. For model development and selection, train only from train_* and score the subsequent val_* outcomes.
  2. After selecting an improvement, refit it on train_* + val_*. At hidden-test time the validation events are observed history, not recommendable outcomes.

Do not use val_* events as features when measuring a validation ranking. They may and should be used when refitting the final hidden-test ranker.

Additional files under /task/data/:

  • candidate_catalog.parquet: the 30,000 retrieval-catalog tracks, ordered by training positive-listen popularity.
  • target_users.parquet: users with at least 20 positive listens in the 90 days before the training cutoff, selected without future labels.
  • validation_preference_state.parquet: active explicit state at the training cutoff, for validation ranking.
  • test_preference_state.parquet: active explicit state after validation, for the final hidden-test ranking. State is liked or disliked; a pair may have both active channels.
  • validation_eligible_candidates.npz and test_eligible_candidates.npz: cutoff-correct candidate sets for every target user. Each contains aligned arrays uids, item_ids, and packed_eligible. For user row r, recover the Boolean item mask with np.unpackbits(packed_eligible[r], count=len(item_ids), bitorder="little").

Validation candidates exclude all train_* encounters. Test candidates exclude all train_* and val_* encounters. Future test interactions are hidden and used only by the separate Harbor verifier.

Discovery Objective

Rank only the candidates returned for the relevant cutoff. Relevance is based on organic behavior in the immediately following window:

  • grade 3: the user organically likes the track;
  • grade 1: the user organically listens to at least 80% of the track;
  • grade 0: otherwise.

If both positive events occur, grade 3 wins. Ranking quality is measured with graded NDCG@10. DCG uses gain 2^grade - 1 and discount 1/log2(rank + 1), then averages per-user NDCG over users with at least one relevant item.

The public evaluator reports this same objective for development, but its score is not a separate acceptance stage. Final acceptance is determined on the hidden test using the same objective. The Yambda logs contain interactions, not impression propensities; treat the organic objective as a robust offline target, not as a causal estimate of online lift.

Deliverable

Submit one final ranking as /app/solution/submission.parquet or /app/solution/submission.csv. It must be a regular file, not a symbolic link. If both files exist, the verifier evaluates submission.parquet and ignores submission.csv.

The ranking must:

  • include the columns uid, item_id, and rank; only these columns are evaluated;
  • use finite, integer-valued entries in all three required columns;
  • cover exactly the users in target_users.parquet, with no missing or extra users;
  • contain exactly 100 rows and 100 distinct items for every target user;
  • contain every integer rank from 1 through 100 exactly once per user; and
  • use only items present in that user's test_eligible_candidates.npz candidate set.

Also leave the improved implementation used to build the artifact at /app/solution/train_current_model.py, along with any local modules it imports. A concise /app/solution/README.md with the diagnosis, before-and-after public score, model change, and submission command is useful for the experiment record, but it is not an automated acceptance gate.

Constraints

  • Write deliverables and intermediate artifacts only under /app/solution/.
  • Treat /task/ and the installed Python environment as read-only.
  • Do not invoke nested agents or attempt to access verifier files, credentials, other trials, or host paths.
  • Do not install packages or use network access except for the model-provider connection managed by Harbor.
  • Do not alter cutoff definitions, target users, candidate eligibility, or relevance labels.
  • Improve the production pipeline in place. Do not substitute an unrelated model family or evade the indexed two-tower serving constraint.
  • The environment includes CPU PyTorch 2.8.0. No accelerator is available.
  • You have up to 60 minutes. Prioritize measured validation improvements, a correct final refit, and a valid submission over broad architecture search.
  • Keep the best valid submission saved throughout the attempt so it survives the deadline.
03

update_topic command

+00:08
Recorded reasoning summary 41 words

Refining Retrieval Performance

I'm now focusing on the production context and the strict performance requirements for our music discovery model. This involves carefully reviewing all prompt details to ensure our improvements align with real-world deployment needs, particularly concerning latency and accuracy.

Recorded reasoning summary 40 words

Optimizing Ranking Logic

I'm digging into the negative sampling strategy within the training objective. My current focus is on diagnosing limitations and devising improvements that fit our strict CPU budget, all while adhering to the established serving and data boundaries.

Recorded reasoning summary 44 words

Validating Model Outputs

I'm currently executing the reproduction commands to validate the model's performance using the provided public datasets and specific stage cutoffs. My focus is on ensuring the generated outputs accurately reflect the training and validation data parameters, especially the discovery quality objective.

Recorded reasoning summary 44 words

Finalizing Submission Details

I'm now consolidating the implementation for final submission, ensuring all deliverables meet the exact specifications. This includes correctly formatting the submission file, including the required columns and adhering to the user and item constraints, while also preparing the improved training script.

Tool callupdate_topicTool call Returned

Tool call · Input

{
  "strategic_intent": "Research the codebase, reproduce the baseline validation score, and understand the model and negative sampling implementation.",
  "title": "Initial Research and Baseline Reproduction",
  "summary": "Starting the music-discovery two-tower project. We will inspect the task files, understand the data structures and model implementation, reproduce the baseline validation performance, and analyze the negative sampling and training objective."
}

Tool response

Current topic: "Initial Research and Baseline Reproduction"
Topic summary: Starting the music-discovery two-tower project. We will inspect the task files, understand the data structures and model implementation, reproduce the baseline validation performance, and analyze the negative sampling and training objective.

Strategic Intent: Research the codebase, reproduce the baseline validation score, and understand the model and negative sampling implementation.
04

list_directory command

+00:18
Tool calllist_directoryTool call Error

Tool call · Input

{
  "dir_path": "/task"
}

Tool response · Tool error

Path not in workspace: Attempted path "/task" resolves outside the allowed workspace directories: /app or the project temp directory: /home/agent/.gemini/tmp/app
05

Inspect task directory, current_model directory, and data directory

+00:20
Tool callrun_shell_commandInspect task directory, current_model directory, and data directory Returned

Tool call · Input

{
  "command": "ls -la /task; ls -la /task/current_model; ls -la /task/data",
  "description": "Inspect task directory, current_model directory, and data directory"
}

Tool response

<untrusted_context>
Output: total 40
dr-xr-xr-x 1 root root 4096 Sep 29 01:18 .
drwxr-xr-x 1 root root 4096 Sep 29 01:21 ..
-r--r--r-- 1 root root    0 Sep 29 01:16 .keep
dr-xr-xr-x 1 root root 4096 Sep 29 01:16 current_model
dr-xr-xr-x 1 root root 4096 Sep 29 01:17 data
-r--r--r-- 1 root root 5774 Sep 29 01:16 evaluate_public.py
-r--r--r-- 1 root root 8265 Sep 29 01:16 ranking_evaluation.py
-r--r--r-- 1 root root 1295 Sep 29 01:16 requirements.txt
total 104
dr-xr-xr-x 1 root root  4096 Sep 29 01:16 .
dr-xr-xr-x 1 root root  4096 Sep 29 01:18 ..
-r--r--r-- 1 root root 80058 Sep 29 01:16 train_current_model.py
-r--r--r-- 1 root root 15985 Sep 29 01:16 two_tower_model.py
total 347392
dr-xr-xr-x 1 root root      4096 Sep 29 01:17 .
dr-xr-xr-x 1 root root      4096 Sep 29 01:18 ..
-r--r--r-- 1 root root    349352 Sep 29 01:16 candidate_catalog.parquet
-r--r--r-- 1 root root     84127 Sep 29 01:16 target_users.parquet
-r--r--r-- 1 root root   7736341 Sep 29 01:16 test_eligible_candidates.npz
-r--r--r-- 1 root root   1092329 Sep 29 01:17 test_preference_state.parquet
-r--r--r-- 1 root root    857213 Sep 29 01:16 train_dislikes.parquet
-r--r--r-- 1 root root   5374652 Sep 29 01:16 train_likes.parquet
-r--r--r-- 1 root root 319183255 Sep 29 01:16 train_listens.parquet
-r--r--r-- 1 root root    155988 Sep 29 01:16 train_undislikes.parquet
-r--r--r-- 1 root root   1855885 Sep 29 01:16 train_unlikes.parquet
-r--r--r-- 1 root root     36571 Sep 29 01:16 val_dislikes.parquet
-r--r--r-- 1 root root    298484 Sep 29 01:16 val_likes.parquet
-r--r--r-- 1 root root   9947609 Sep 29 01:16 val_listens.parquet
-r--r--r-- 1 root root      7845 Sep 29 01:16 val_undislikes.parquet
-r--r--r-- 1 root root     72536 Sep 29 01:16 val_unlikes.parquet
-r--r--r-- 1 root root   7573821 Sep 29 01:16 validation_eligible_candidates.npz
-r--r--r-- 1 root root   1061761 Sep 29 01:17 validation_preference_state.parquet
Process Group PGID: 1612
</untrusted_context>
06

List files in /app and /app/solution

+00:24
Tool callrun_shell_commandList files in /app and /app/solution Returned

Tool call · Input

{
  "description": "List files in /app and /app/solution",
  "command": "ls -la /app; ls -la /app/solution"
}

Tool response

<untrusted_context>
Output: total 12
drwxr-xr-x 3 agent agent 4096 Sep 29 01:18 .
drwxr-xr-x 1 root  root  4096 Sep 29 01:21 ..
drwxr-xr-x 2 agent agent 4096 Sep 29 01:18 solution
total 8
drwxr-xr-x 2 agent agent 4096 Sep 29 01:18 .
drwxr-xr-x 3 agent agent 4096 Sep 29 01:18 ..
Process Group PGID: 1617
</untrusted_context>
07

Copy code to /app/solution/ and check system resources

+00:26
Recorded reasoning summary 36 words

Organizing workspace and resources

I'm currently copying the code from the /task/current_model/ directory to /app/solution/ for easier access. Simultaneously, I'm reviewing the available CPU cores and memory to get a clear picture of my computational environment.

Tool callrun_shell_commandCopy code to /app/solution/ and check system resources Returned

Tool call · Input

{
  "description": "Copy code to /app/solution/ and check system resources",
  "command": "cp -r /task/current_model/* /app/solution/ && cp /task/evaluate_public.py /app/solution/ && cp /task/ranking_evaluation.py /app/solution/\nlscpu | grep \"Model name\\|CPU(s):\"\nfree -h\n"
}

Tool response

<untrusted_context>
Output: CPU(s):                                  8
Model name:                              AMD EPYC 7R13 Processor
NUMA node0 CPU(s):                       0-7
/usr/bin/bash: line 6: free: command not found
Exit Code: 127
Process Group PGID: 1621
</untrusted_context>
08

Check system memory

+00:28
Tool callrun_shell_commandCheck system memory Returned

Tool call · Input

{
  "command": "cat /proc/meminfo | head -n 5",
  "description": "Check system memory"
}

Tool response

<untrusted_context>
Output: MemTotal:       15988968 kB
MemFree:         1419612 kB
MemAvailable:   14482864 kB
Buffers:          247820 kB
Cached:         12490908 kB
Process Group PGID: 1629
</untrusted_context>
09

read_file evaluate_public.py

+00:30
Recorded reasoning summary 30 words

Running Baseline Reproduction

I'm initiating the baseline reproduction command to assess initial performance. This involves running the provided Python script to establish a performance benchmark on the current hardware configuration.

Tool callread_file/app/solution/evaluate_public.py Returned

Tool call · Input

{
  "end_line": 150,
  "start_line": 1,
  "file_path": "/app/solution/evaluate_public.py"
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 1-150 of 158 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 151.

--- FILE CONTENT (truncated) ---
#!/usr/bin/env python3
"""Score a validation-stage ranking against public discovery labels.

``build_task.py`` publishes this module with the solver-visible task files. It
loads target users, validation eligibility, and validation-window events from
the adjacent ``data`` directory, then evaluates one ranking supplied on the
command line. Stage-independent mechanics come from the adjacent public
``ranking_evaluation.py`` module. The builder installs the same checked-in
module in the private judge, so public and private scoring mechanics cannot
drift. A relevant candidate receives grade 3 for an organic like or grade 1 for
an organic listen with at least 80 percent completion; a like takes precedence
when both events exist.

Before scoring, the ranking must contain exactly 100 distinct eligible items
for every target user, with integer-valued ``uid``, ``item_id``, and ``rank``
columns and ranks 1 through 100 exactly once per user. Extra columns are
ignored. Quality is graded NDCG@10, averaged only over users who have at least
one eligible relevant item in the validation window.

The evaluator prints a JSON object containing the model path and scores. It
does not apply the task's pass threshold; its purpose is model development and
selection. The private judge applies the threshold to the final submission.

Usage::

    python evaluate_public.py <validation-ranking.parquet|csv>
"""
from __future__ import annotations

import json
import sys
from pathlib import Path

import pandas as pd

from ranking_evaluation import (
    CandidateSet,
    RankingValidationError,
    ranked_items,
    read_ranking,
    score_rankings,
    validate_ranking,
)


HERE = Path(__file__).resolve().parent
DATA = HERE / "data"
LISTEN_STRONG = 80


def validation_truth(
    eligibility: CandidateSet, targets: set[int]
) -> dict[int, dict[int, int]]:
    """Build cutoff-correct graded relevance from public validation events.

    Only target-user events for eligible candidates are retained. Organic
    listens completed to at least 80 percent receive grade 1, and organic likes
    receive grade 3. Repeated user-item events are collapsed, and processing
    likes second ensures that grade 3 wins over grade 1.

    Args:
        eligibility: Validation-cutoff candidate membership service.
        targets: Complete set of target user IDs.

    Returns:
        A nested ``uid -> item_id -> grade`` mapping. Users without an eligible
        relevant event are omitted.
    """
    listens = pd.read_parquet(DATA / "val_listens.parquet")
    likes = pd.read_parquet(DATA / "val_likes.parquet")
    strong = listens[
        listens.uid.isin(targets)
        & (listens.is_organic == 1)
        & (listens.played_ratio_pct >= LISTEN_STRONG)
    ][["uid", "item_id"]].drop_duplicates()
    organic_likes = likes[
        likes.uid.isin(targets) & (likes.is_organic == 1)
    ][["uid", "item_id"]].drop_duplicates()

    graded: dict[int, dict[int, int]] = {}
    for raw_uid, raw_item in strong.itertuples(index=False, name=None):
        uid, item = int(raw_uid), int(raw_item)
        if eligibility.is_eligible(uid, item):
            graded.setdefault(uid, {})[item] = 1
    for raw_uid, raw_item in organic_likes.itertuples(index=False, name=None):
        uid, item = int(raw_uid), int(raw_item)
        if eligibility.is_eligible(uid, item):
            graded.setdefault(uid, {})[item] = 3
    return graded


def load_submission(
    path: Path, eligibility: CandidateSet, targets: set[int]
) -> dict[int, list[int]]:
    """Load and validate a public validation ranking.

    Files ending in ``.parquet`` are read as parquet; every other suffix is
    read as CSV. The required columns must be integer-valued, cover exactly the
    target-user set, contain 100 rows and ranks 1 through 100 per user, avoid
    duplicate user-item pairs, and contain only cutoff-eligible items.

    Args:
        path: Ranking file to read.
        eligibility: Validation-cutoff candidate membership service.
        targets: Exact set of users the ranking must cover.

    Returns:
        A ``uid -> ranked item IDs`` mapping ordered by ascending rank.

    Raises:
        ValueError: If the ranking violates the required schema or invariants.
    """
    frame = validate_ranking(read_ranking(path), targets)
    if not all(
        eligibility.is_eligible(uid, item)
        for uid, item in frame[["uid", "item_id"]].itertuples(index=False, name=None)
    ):
        raise RankingValidationError(
            "submission contains an item rejected by eligibility service"
        )
    return ranked_items(frame)


def score(
    ranked: dict[int, list[int]],
    graded: dict[int, dict[int, int]],
) -> dict[str, float | int]:
    """Aggregate per-user NDCG@10 over users with public relevance labels.

    Args:
        ranked: Ranked item IDs for every target user.
        graded: Eligible validation relevance keyed by user and item.

    Returns:
        The six-decimal ``quality_ndcg@10`` value and number of scored users.
    """
    return score_rankings(ranked, graded)


def main() -> None:
    """Run the public evaluator CLI and print its JSON score report."""
    targets_frame = pd.read_parquet(DATA / "target_users.parquet")
    targets = set(targets_frame.uid.astype(int))
    eligibility = CandidateSet(DATA / "validation_eligible_candidates.npz")
    graded = validation_truth(eligibility, targets)

    if len(sys.argv) != 2:
        raise SystemExit(
            "usage: evaluate_public.py <validation-ranking.parquet|csv>"
        )
10

Count lines in train_current_model.py and two_tower_model.py

+00:33
Tool callrun_shell_commandCount lines in train_current_model.py and two_tower_model.py Returned

Tool call · Input

{
  "command": "wc -l /app/solution/train_current_model.py /app/solution/two_tower_model.py",
  "description": "Count lines in train_current_model.py and two_tower_model.py"
}

Tool response

<untrusted_context>
Output: 2164 /app/solution/train_current_model.py
  433 /app/solution/two_tower_model.py
 2597 total
Process Group PGID: 1633
</untrusted_context>
11

grep_search command

+00:35
Tool callgrep_searchTool call Returned

Tool call · Input

{
  "dir_path": "/app/solution",
  "pattern": "^(class |def |if __name__)",
  "include_pattern": "train_current_model.py"
}

Tool response

Found 44 matches for pattern "^(class |def |if __name__)" in path "/app/solution" (filter: "train_current_model.py"):
---
File: train_current_model.py
L41: class Config:
L76: class CandidateSet:
L99: class SequenceData:
L127: class TargetPartition:
L140: def log(message: str) -> None:
L144: def seed_everything(seed: int) -> None:
L150: def model_config(config: Config) -> base.TowerConfig:
L174: def append_state_snapshot(
L190: def causal_activity_features(
L247: def build_sequence_parts(
L314: def final_user_features(
L341: def prepare_data(
L471: def cache_metadata(stage: str, config: Config) -> dict[str, object]:
L481: def save_cache(
L493: def load_cache(path: Path, stage: str, config: Config) -> SequenceData:
L511: def load_or_prepare(
L534: def build_item_correction(
L578: def build_known_positive_filter(
L609: def invalid_full_history_negatives(
L630: def draw_full_history_filtered_negatives(
L724: def draw_training_negatives(
L763: def event_sequence(
L774: def pool_explicit_states(
L798: def user_queries(
L813: def candidate_vectors(
L828: def history_windows(
L845: def corrected_negative_loss(
L867: def retained_target_window_starts(
L888: def chronological_target_partition(
L914: def load_organic_like_outcomes(
L955: def build_target_weights(
L1035: def build_dense_block(
L1111: def score_target_microbatches(
L1198: def release_accelerator_cache(device: torch.device) -> None:
L1203: def run_training_epoch(
L1364: def evaluate_validation_bce(
L1488: def snapshot_model(model: nn.Module) -> dict[str, torch.Tensor]:
L1495: def save_epoch_checkpoint(
L1521: def train_model(
L1782: def inference_queries(
L1861: def rank_candidates(
L1912: def write_ranking(frame: pd.DataFrame, output: Path) -> None:
L1922: def main() -> int:
L2163: if __name__ == "__main__":
---
12

Run baseline production validation training and evaluate public score

+00:39
Recorded reasoning summary 40 words

Refining Negative Sampling

I'm currently focused on optimizing how we handle negative samples. My latest efforts involve examining specific function names, like invalid_full_history_negatives and draw_training_negatives, to identify potential improvements in their logic and efficiency, particularly around corrected_negative_loss and weight building.

Tool callrun_shell_commandRun baseline production validation training and evaluate public score Returned

Tool call · Input

{
  "description": "Run baseline production validation training and evaluate public score",
  "command": "python /task/current_model/train_current_model.py \\\n  --stage validation \\\n  --public-dir /task \\\n  --output /app/solution/production_validation.parquet\npython /task/evaluate_public.py /app/solution/production_validation.parquet"
}

Tool response

<untrusted_context>
Output: loaded explicit events: rows=720,270 users=8,220
prepared users=1,000 tokens=2,090,746 states=35,727 elapsed=4.9s
prepared users=2,000 tokens=4,301,266 states=71,242 elapsed=9.9s
prepared users=3,000 tokens=6,486,146 states=109,471 elapsed=15.1s
prepared users=4,000 tokens=8,793,043 states=148,210 elapsed=20.5s
prepared users=5,000 tokens=10,992,205 states=182,596 elapsed=25.4s
prepared users=6,000 tokens=13,061,727 states=217,148 elapsed=30.1s
prepared users=7,000 tokens=15,334,418 states=256,914 elapsed=35.6s
prepared users=8,000 tokens=17,462,672 states=296,703 elapsed=40.9s
prepared users=9,000 tokens=19,568,405 states=331,551 elapsed=45.7s
target users without qualifying catalog sequence=7
prepared stage=validation sequence_users=9,135 tokens=20,056,329 next_item_targets=20,047,194 states=339,133
chronological BCE window: train=1,052,953 validation=130,103 selected=1,183,056 discarded_old_targets=18,864,138 all=20,047,194
inbatch correction: min=0.250 mean_on_targets=1.001 max=4.000
target weighting=organic-strong min=0.250 mean=0.575 max=1.000
full-history false-negative filter: users=9,135 unique_user_items=5,524,275 bytes=34,256,250
epoch=1/1 batches=250 targets=987,417 batch_bce=0.547529 running_bce=0.541614 elapsed=198.0s
epoch=1/1 train_loss=0.53984 validation_loss=0.49664 pair_accuracy=0.755 train_targets=1,052,953 validation_targets=130,103 train_seconds=211.0 validation_seconds=15.5
restored best validation-BCE checkpoint: epoch=1 loss=0.496636
ranked users=1,024/8,456
ranked users=2,048/8,456
ranked users=3,072/8,456
ranked users=4,096/8,456
ranked users=5,120/8,456
ranked users=6,144/8,456
ranked users=7,168/8,456
ranked users=8,192/8,456
ranked users=8,456/8,456
{
  "baseline": "yambda-windowed-sequence-two-tower-base",
  "stage": "validation",
  "output": "/app/solution/production_validation.parquet",
  "rows": 845600,
  "users": 8456,
  "runtime_seconds": 358.832,
  "public_inputs_only": true,
  "architecture": {
    "family": "pure-windowed-sequence-two-tower",
    "sequence_training": "every-adjacent-target-within-recent-chronological-window",
    "sequence_encoder": "one-layer-GRU-dense-timestep-loss",
    "bptt_hidden_state": "carried-and-detached",
    "model_selection": "chronological-validation-BCE-early-stopping",
    "loss_execution": "gradient-accumulated-microbatches",
    "user_id_embedding": false,
    "user_mlp": "582-512-256-192",
    "item_mlp": "196-512-256-192",
    "normalization": "none",
    "score": "raw-dot-product",
    "objective": "sample-weighted-BCE-at-every-timestep",
    "negative_sampling": "24-uniform-plus-8-propensity-corrected-inbatch",
    "false_negative_filter": "full-training-history",
    "target_weighting": "organic-strong"
  },
  "config": {
    "bptt_steps": 100,
    "user_batch_size": 64,
    "embedding_dim": 192,
    "hidden_dim": 192,
    "user_hidden_1": 512,
    "user_hidden_2": 256,
    "item_hidden_1": 512,
    "item_hidden_2": 256,
    "dropout": 0.05,
    "epochs": 1,
    "learning_rate": 0.001,
    "weight_decay": 1e-05,
    "gradient_clip": 2.0,
    "loss_microbatch_size": 65536,
    "uniform_negatives": 24,
    "inbatch_negatives": 8,
    "inbatch_correction_power": 0.5,
    "inbatch_correction_min": 0.25,
    "inbatch_correction_max": 4.0,
    "negative_filter_scope": "full-training-history",
    "target_weighting": "organic-strong",
    "ordinary_target_weight": 0.25,
    "organic_strong_target_weight": 1.0,
    "organic_like_target_weight": 3.0,
    "discovery_horizon_days": 7,
    "validation_fraction": 0.1,
    "max_train_targets_per_user": 128,
    "max_validation_targets_per_user": 16,
    "early_stopping_patience": 1,
    "early_stopping_min_delta": 0.0001,
    "seed": 29
  },
  "sequence_tokens": 20056329,
  "all_next_item_targets": 20047194,
  "selected_training_targets": 1052953,
  "selected_validation_targets": 130103,
  "discarded_old_targets": 18864138,
  "training_history": [
    {
      "epoch": 1.0,
      "loss": 0.5398380451095077,
      "positive_logit": 0.742779958851944,
      "negative_logit": -0.6222247018676265,
      "pair_accuracy": 0.7547733612041563,
      "targets": 1052953.0,
      "target_weight_sum": 632551.0,
      "batches": 266.0,
      "seconds": 211.018207221,
      "validation_loss": 0.4966362150129709,
      "validation_targets": 130103.0,
      "validation_target_weight_sum": 78769.25,
      "validation_seconds": 15.520032933000039
    }
  ],
  "embedding_diagnostics": {
    "query_norm_mean": 1.603016972541809,
    "query_norm_std": 0.7697497010231018,
    "item_norm_mean": 1.7570281028747559,
    "item_norm_std": 0.8279485702514648
  },
  "torch_version": "2.8.0+cpu",
  "device": "cpu"
}
{
  "model": "/app/solution/production_validation.parquet",
  "scores": {
    "quality_ndcg@10": 0.02128,
    "quality_users": 4263
  }
}
Process Group PGID: 1638
</untrusted_context>
13

read_file train_current_model.py

+06:50
Recorded reasoning summary 35 words

Completing Baseline Reproduction

The initial reproduction run has concluded. I observed a runtime of approximately 358 seconds. The quality_ndcg@10 score registered at 0.02128 for 4,263 users. I'm now examining the generated JSON output and diagnostics.

Recorded reasoning summary 47 words

Investigating Negative Sampling

I'm now diving into train_current_model.py and two_tower_model.py to scrutinize the negative sampling strategy and its impact on the training objective. My focus is on understanding how these samples are selected and utilized within the loss calculation, aiming to identify potential limitations for future improvements.

Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "file_path": "/app/solution/train_current_model.py",
  "start_line": 40,
  "end_line": 140
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 40-140 of 2165 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 141.

--- FILE CONTENT (truncated) ---
@dataclass(frozen=True)
class Config:
    bptt_steps: int = 100
    user_batch_size: int = 64
    embedding_dim: int = 192
    hidden_dim: int = 192
    user_hidden_1: int = 512
    user_hidden_2: int = 256
    item_hidden_1: int = 512
    item_hidden_2: int = 256
    dropout: float = 0.05
    epochs: int = 1
    learning_rate: float = 1.0e-3
    weight_decay: float = 1.0e-5
    gradient_clip: float = 2.0
    loss_microbatch_size: int = 65_536
    uniform_negatives: int = 24
    inbatch_negatives: int = 8
    inbatch_correction_power: float = 0.5
    inbatch_correction_min: float = 0.25
    inbatch_correction_max: float = 4.0
    negative_filter_scope: str = "full-training-history"
    target_weighting: str = "organic-strong"
    ordinary_target_weight: float = 0.25
    organic_strong_target_weight: float = 1.0
    organic_like_target_weight: float = 3.0
    discovery_horizon_days: int = 7
    validation_fraction: float = 0.10
    max_train_targets_per_user: int = 128
    max_validation_targets_per_user: int = 16
    early_stopping_patience: int = 1
    early_stopping_min_delta: float = 1.0e-4
    seed: int = 29


@dataclass(frozen=True)
class CandidateSet:
    uids: np.ndarray
    item_ids: np.ndarray
    packed: np.ndarray

    @classmethod
    def read(cls, path: Path) -> "CandidateSet":
        with np.load(path, allow_pickle=False) as artifact:
            result = cls(
                uids=artifact["uids"].astype(np.int64, copy=True),
                item_ids=artifact["item_ids"].astype(np.int64, copy=True),
                packed=artifact["packed_eligible"].astype(np.uint8, copy=True),
            )
        expected = (len(result.uids), (len(result.item_ids) + 7) // 8)
        if result.packed.shape != expected:
            raise ValueError(
                f"invalid candidate artifact shape {result.packed.shape}; "
                f"expected {expected}"
            )
        return result


@dataclass(frozen=True)
class SequenceData:
    item_ids: np.ndarray
    item_features: np.ndarray
    user_ids: np.ndarray
    offsets: np.ndarray
    sequence_timestamps: np.ndarray
    sequence_items: np.ndarray
    event_features: np.ndarray
    activity_features: np.ndarray
    state_ids: np.ndarray
    liked_states: np.ndarray
    disliked_states: np.ndarray
    state_counts: np.ndarray
    inference_user_rows: np.ndarray
    inference_liked_items: np.ndarray
    inference_disliked_items: np.ndarray
    inference_user_features: np.ndarray

    @property
    def lengths(self) -> np.ndarray:
        return np.diff(self.offsets)

    @property
    def target_count(self) -> int:
        return int(np.maximum(self.lengths - 1, 0).sum())


@dataclass(frozen=True)
class TargetPartition:
    """A contiguous recent target window and its chronological BCE split."""

    window_starts: np.ndarray
    training_counts: np.ndarray
    validation_counts: np.ndarray
    history_training_counts: np.ndarray

    @property
    def selected_count(self) -> int:
        return int(self.training_counts.sum() + self.validation_counts.sum())


def log(message: str) -> None:
14

read_file train_current_model.py

+06:52
Recorded reasoning summary 42 words

Analyzing Negative Sampling

I'm currently examining the functions responsible for negative sampling and loss calculation, specifically focusing on build_item_correction, build_known_positive_filter, invalid_full_history_negatives, draw_full_history_filtered_negatives, draw_training_negatives, and corrected_negative_loss. This analysis will help refine our approach to generating and incorporating negative samples into the training process.

Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "start_line": 530,
  "file_path": "/app/solution/train_current_model.py",
  "end_line": 650
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 530-650 of 2165 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 651.

--- FILE CONTENT (truncated) ---
        save_cache(cache, prepared, stage, config)
    return prepared, built_eligibility


def build_item_correction(
    prepared: SequenceData,
    config: Config,
    target_starts: np.ndarray,
    target_counts: np.ndarray,
) -> torch.Tensor:
    """Estimate in-batch propensities from the selected training targets."""
    counts = np.zeros(len(prepared.item_ids), dtype=np.float64)
    for user_row, count in enumerate(target_counts):
        if not count:
            continue
        offset = int(prepared.offsets[user_row])
        target_start = int(target_starts[user_row])
        counts += np.bincount(
            prepared.sequence_items[
                offset
                + target_start
                + 1 : offset
                + target_start
                + int(count)
                + 1
            ].astype(np.int64),
            minlength=len(prepared.item_ids),
        )
    total = float(counts.sum())
    probabilities = (counts + 1.0) / (total + len(counts))
    raw = np.power(
        (1.0 / len(counts)) / probabilities,
        config.inbatch_correction_power,
    )
    normalization = float(np.sum(counts * raw) / max(total, 1.0))
    correction = np.clip(
        raw / max(normalization, 1.0e-12),
        config.inbatch_correction_min,
        config.inbatch_correction_max,
    ).astype(np.float32)
    mean_on_targets = float(np.sum(counts * correction) / max(total, 1.0))
    log(
        f"inbatch correction: min={correction.min():.3f} "
        f"mean_on_targets={mean_on_targets:.3f} max={correction.max():.3f}"
    )
    return torch.from_numpy(correction)


def build_known_positive_filter(
    prepared: SequenceData, training_counts: np.ndarray
) -> np.ndarray:
    """Pack each user's complete public-training positive-item set."""
    width = (len(prepared.item_ids) + 7) // 8
    packed = np.zeros((len(prepared.user_ids), width), dtype=np.uint8)
    retained = 0
    for user_row, target_count in enumerate(training_counts):
        if not target_count:
            continue
        offset = int(prepared.offsets[user_row])
        # T adjacent targets consume sequence positions 0 through T.  The
        # chronological BCE suffix starts at T + 1 and is intentionally absent.
        items = np.unique(
            prepared.sequence_items[
                offset : offset + int(target_count) + 1
            ].astype(np.int64)
        )
        byte_columns = items >> 3
        bit_values = np.left_shift(
            np.uint8(1), (items & 7).astype(np.uint8)
        )
        np.bitwise_or.at(packed[user_row], byte_columns, bit_values)
        retained += len(items)
    log(
        f"full-history false-negative filter: users={len(prepared.user_ids):,} "
        f"unique_user_items={retained:,} bytes={packed.nbytes:,}"
    )
    return packed


def invalid_full_history_negatives(
    negatives: np.ndarray,
    targets: np.ndarray,
    user_rows: np.ndarray,
    known_positive_packed: np.ndarray,
    liked_items: np.ndarray,
) -> np.ndarray:
    """Return row-level invalid negatives using the complete training prefix."""
    byte_columns = negatives >> 3
    bit_columns = negatives & 7
    known = known_positive_packed[user_rows[:, None], byte_columns]
    invalid = ((known >> bit_columns) & 1).astype(bool)
    invalid |= negatives == targets[:, None]
    invalid |= (negatives[:, :, None] == liked_items[:, None, :]).any(axis=2)
    for column in range(1, negatives.shape[1]):
        invalid[:, column] |= (
            negatives[:, column, None] == negatives[:, :column]
        ).any(axis=1)
    return invalid


def draw_full_history_filtered_negatives(
    targets: torch.Tensor,
    user_rows: np.ndarray,
    liked_items: torch.Tensor,
    known_positive_packed: np.ndarray,
    n_items: int,
    config: Config,
    item_correction: torch.Tensor,
    generator: torch.Generator,
    device: torch.device,
) -> tuple[torch.Tensor, torch.Tensor]:
    """Draw mixed negatives and reject all known public-training positives."""
    targets_cpu = targets.detach().cpu().numpy().astype(np.int64, copy=False)
    liked_cpu = liked_items.detach().cpu().numpy().astype(np.int64, copy=False)
    batch_size = len(targets_cpu)
    uniform = torch.randint(
        n_items,
        (batch_size, config.uniform_negatives),
        generator=generator,
        device="cpu",
    )
15

read_file train_current_model.py

+07:13
Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "end_line": 780,
  "start_line": 651,
  "file_path": "/app/solution/train_current_model.py"
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 651-780 of 2165 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 781.

--- FILE CONTENT (truncated) ---
    inbatch = torch.empty((batch_size, 0), dtype=torch.long)
    corrected_count = 0
    if config.inbatch_negatives:
        unique_targets = torch.unique(targets.detach().cpu())
        corrected_count = min(
            config.inbatch_negatives, max(len(unique_targets) - 1, 0)
        )
        if corrected_count:
            priorities = torch.rand(
                (batch_size, len(unique_targets)), generator=generator
            )
            priorities.masked_fill_(
                unique_targets[None, :].eq(
                    torch.from_numpy(targets_cpu)[:, None]
                ),
                -1.0,
            )
            columns = torch.topk(
                priorities, k=corrected_count, dim=1
            ).indices
            inbatch = unique_targets[columns]
        if corrected_count < config.inbatch_negatives:
            filler = torch.randint(
                n_items,
                (batch_size, config.inbatch_negatives - corrected_count),
                generator=generator,
                device="cpu",
            )
            inbatch = torch.cat([inbatch, filler], dim=1)

    negatives = torch.cat([uniform, inbatch], dim=1).numpy()
    correction = np.ones_like(negatives, dtype=np.float32)
    if corrected_count:
        correction[
            :, config.uniform_negatives : config.uniform_negatives + corrected_count
        ] = item_correction[inbatch[:, :corrected_count]].numpy()
    for _ in range(32):
        invalid = invalid_full_history_negatives(
            negatives,
            targets_cpu,
            user_rows,
            known_positive_packed,
            liked_cpu,
        )
        if not np.any(invalid):
            return (
                torch.from_numpy(negatives).to(device),
                torch.from_numpy(correction).to(device),
            )
        replacements = torch.randint(
            n_items,
            (int(invalid.sum()),),
            generator=generator,
            device="cpu",
        ).numpy()
        negatives[invalid] = replacements
        # Rejected in-batch items become ordinary uniform draws.
        correction[invalid] = 1.0
    invalid = invalid_full_history_negatives(
        negatives,
        targets_cpu,
        user_rows,
        known_positive_packed,
        liked_cpu,
    )
    if np.any(invalid):
        raise RuntimeError("full-history negative resampling failed")
    return (
        torch.from_numpy(negatives).to(device),
        torch.from_numpy(correction).to(device),
    )


def draw_training_negatives(
    positive_items: torch.Tensor,
    known_history: torch.Tensor,
    liked_items: torch.Tensor,
    user_rows: np.ndarray,
    known_positive_packed: np.ndarray | None,
    prepared: SequenceData,
    config: Config,
    item_correction: torch.Tensor,
    generator: torch.Generator,
    device: torch.device,
) -> tuple[torch.Tensor, torch.Tensor]:
    if config.negative_filter_scope == "full-training-history":
        if known_positive_packed is None:
            raise RuntimeError("full-history negative filter was not built")
        return draw_full_history_filtered_negatives(
            positive_items,
            user_rows,
            liked_items,
            known_positive_packed,
            len(prepared.item_ids),
            config,
            item_correction,
            generator,
            device,
        )
    return base.draw_filtered_mixed_negatives(
        positive_items,
        known_history,
        liked_items,
        len(prepared.item_ids),
        config.uniform_negatives,
        config.inbatch_negatives,
        item_correction,
        generator,
        device,
    )


def event_sequence(
    model: base.SequentialTwoTower,
    items: torch.Tensor,
    features: torch.Tensor,
    hidden: torch.Tensor,
) -> tuple[torch.Tensor, torch.Tensor]:
    inputs = torch.cat([model.context_embedding(items), features], dim=-1)
    projected = model.event_projection(inputs)
    return model.sequence_encoder(projected, hidden)


def pool_explicit_states(
    model: base.SequentialTwoTower,
    prepared: SequenceData,
    state_ids: np.ndarray,
    device: torch.device,
) -> tuple[torch.Tensor, torch.Tensor, torch.Tensor]:
    unique_states, inverse = np.unique(state_ids, return_inverse=True)
16

read_file train_current_model.py

+07:17
Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "end_line": 950,
  "file_path": "/app/solution/train_current_model.py",
  "start_line": 780
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 780-950 of 2165 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 951.

--- FILE CONTENT (truncated) ---
    unique_states, inverse = np.unique(state_ids, return_inverse=True)
    liked_items = torch.from_numpy(
        prepared.liked_states[unique_states].astype(np.int64)
    ).to(device)
    disliked_items = torch.from_numpy(
        prepared.disliked_states[unique_states].astype(np.int64)
    ).to(device)
    liked_vectors = model._mean_context_channel(liked_items)
    disliked_vectors = model._mean_context_channel(disliked_items)
    inverse_rows = torch.from_numpy(inverse.astype(np.int64)).to(device)
    counts = prepared.state_counts[state_ids]
    return (
        liked_vectors[inverse_rows],
        disliked_vectors[inverse_rows],
        torch.from_numpy(counts.astype(np.float32)).to(device),
    )


def user_queries(
    model: base.SequentialTwoTower,
    sequence_vectors: torch.Tensor,
    liked_vectors: torch.Tensor,
    disliked_vectors: torch.Tensor,
    user_features: torch.Tensor,
) -> torch.Tensor:
    return model.user_tower(
        torch.cat(
            [sequence_vectors, liked_vectors, disliked_vectors, user_features],
            dim=1,
        )
    )


def candidate_vectors(
    model: base.SequentialTwoTower,
    positives: torch.Tensor,
    negatives: torch.Tensor,
) -> tuple[torch.Tensor, torch.Tensor]:
    all_items = torch.cat([positives, negatives.reshape(-1)])
    unique_items, inverse = torch.unique(all_items, return_inverse=True)
    encoded = model.encode_items(unique_items)
    positive_vectors = encoded[inverse[: len(positives)]]
    negative_vectors = encoded[inverse[len(positives) :]].reshape(
        len(positives), negatives.shape[1], -1
    )
    return positive_vectors, negative_vectors


def history_windows(
    sequence: np.ndarray,
    start: int,
    count: int,
    width: int,
    padding_item: int,
) -> np.ndarray:
    base_start = max(0, start - width + 1)
    segment = sequence[base_start : start + count]
    padded = np.concatenate(
        [np.full(width - 1, padding_item, dtype=np.uint16), segment]
    )
    windows = np.lib.stride_tricks.sliding_window_view(padded, width)
    offset = start - base_start
    return windows[offset : offset + count].copy()


def corrected_negative_loss(
    logits: torch.Tensor,
    correction: torch.Tensor,
    config: Config,
) -> torch.Tensor:
    raw = F.softplus(logits)
    total = config.uniform_negatives + config.inbatch_negatives
    result = torch.zeros(len(logits), device=logits.device)
    if config.uniform_negatives:
        result += config.uniform_negatives * raw[
            :, : config.uniform_negatives
        ].mean(dim=1)
    if config.inbatch_negatives:
        selected = slice(config.uniform_negatives, total)
        weights = correction[:, selected]
        result += config.inbatch_negatives * (
            (raw[:, selected] * weights).sum(dim=1)
            / weights.sum(dim=1).clamp_min(1.0e-6)
        )
    return result / total


def retained_target_window_starts(
    total_targets: np.ndarray,
    validation_counts: np.ndarray,
    training_counts: np.ndarray,
) -> np.ndarray:
    """Return the discarded prefix before the retained chronological suffix."""
    training_region_ends = total_targets - validation_counts
    window_starts = training_region_ends - training_counts
    if (
        np.any(window_starts < 0)
        or np.any(training_counts < 0)
        or np.any(validation_counts < 0)
    ):
        raise RuntimeError("chronological target partition produced negative counts")
    if not np.array_equal(
        window_starts + training_counts + validation_counts, total_targets
    ):
        raise RuntimeError("chronological target window is not a final contiguous suffix")
    return window_starts


def chronological_target_partition(
    prepared: SequenceData,
    validation_fraction: float,
    max_train_targets_per_user: int,
    max_validation_targets_per_user: int,
) -> TargetPartition:
    """Select a recent contiguous window with a final out-of-time BCE suffix."""
    totals = np.maximum(prepared.lengths - 1, 0).astype(np.int64)
    validation = np.floor(totals * validation_fraction).astype(np.int64)
    validation[(totals >= 2) & (validation == 0)] = 1
    if max_validation_targets_per_user:
        validation = np.minimum(validation, max_validation_targets_per_user)

    history_training = totals - validation
    training = history_training.copy()
    if max_train_targets_per_user:
        training = np.minimum(training, max_train_targets_per_user)
    window_starts = retained_target_window_starts(totals, validation, training)
    return TargetPartition(
        window_starts=window_starts,
        training_counts=training,
        validation_counts=validation,
        history_training_counts=history_training,
    )


def load_organic_like_outcomes(
    public: Path, stage: str, item_ids: np.ndarray
) -> dict[int, dict[int, np.ndarray]]:
    """Load mapped organic-like timestamps from public fitting history."""
    prefixes = ("train",) if stage == "validation" else ("train", "val")
    frames = [
        pd.read_parquet(
            public / "data" / f"{prefix}_likes.parquet",
            columns=["uid", "timestamp", "item_id", "is_organic"],
        )
        for prefix in prefixes
    ]
    likes = pd.concat(frames, ignore_index=True)
    likes = likes[likes.is_organic == 1].copy()
    mapped = pd.Index(item_ids).get_indexer(
        likes.item_id.to_numpy(dtype=np.int64)
    )
    likes = likes.loc[mapped >= 0, ["uid", "timestamp"]].copy()
    likes["item"] = mapped[mapped >= 0].astype(np.int32, copy=False)
    likes = likes.sort_values(["uid", "item", "timestamp"], kind="stable")
    nested: dict[int, dict[int, list[int]]] = {}
    for raw_uid, raw_timestamp, raw_item in likes.itertuples(
        index=False, name=None
    ):
        nested.setdefault(int(raw_uid), {}).setdefault(int(raw_item), []).append(
            int(raw_timestamp)
        )
    result = {
        uid: {
            item: np.asarray(timestamps, dtype=np.int64)
            for item, timestamps in items.items()
        }
        for uid, items in nested.items()
    }
    log(
        f"loaded organic-like outcomes: rows={len(likes):,} "
        f"users={len(result):,}"
17

read_file train_current_model.py

+07:19
Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "file_path": "/app/solution/train_current_model.py",
  "start_line": 951,
  "end_line": 1100
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 951-1100 of 2165 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 1101.

--- FILE CONTENT (truncated) ---
    )
    return result


def build_target_weights(
    public: Path,
    stage: str,
    prepared: SequenceData,
    training_counts: np.ndarray,
    config: Config,
) -> np.ndarray:
    """Build nonzero per-token weights without dropping adjacent targets."""
    if config.target_weighting == "uniform":
        weights = np.ones(len(prepared.sequence_items), dtype=np.float32)
    else:
        weights = np.full(
            len(prepared.sequence_items),
            config.ordinary_target_weight,
            dtype=np.float32,
        )
        organic_strong = (
            (prepared.event_features[:, 0] > 0.5)
            & (prepared.event_features[:, 1] >= 0.8)
        )
        weights[organic_strong] = config.organic_strong_target_weight
        if config.target_weighting == "discovery-graded":
            like_outcomes = load_organic_like_outcomes(
                public, stage, prepared.item_ids
            )
            history_end = (
                base.TRAIN_END if stage == "validation" else base.VALIDATION_END
            )
            horizon = config.discovery_horizon_days * base.DAY
            grade_three = 0
            for user_row, uid in enumerate(prepared.user_ids):
                start = int(prepared.offsets[user_row])
                end = int(prepared.offsets[user_row + 1])
                if end - start < 2:
                    continue
                last_training_target = start + int(training_counts[user_row])
                first_validation_target = last_training_target + 1
                split_timestamp = (
                    int(prepared.sequence_timestamps[first_validation_target])
                    if first_validation_target < end
                    else history_end
                )
                user_likes = like_outcomes.get(int(uid), {})
                seen = {int(prepared.sequence_items[start])}
                for position in range(start + 1, end):
                    item = int(prepared.sequence_items[position])
                    novel = item not in seen
                    seen.add(item)
                    if not novel:
                        # Repeats remain training examples, but they cannot be
                        # eligible discovery outcomes at the corresponding
                        # cutoff and therefore keep only the ordinary weight.
                        weights[position] = config.ordinary_target_weight
                        continue
                    timestamps = user_likes.get(item)
                    if timestamps is None:
                        continue
                    timestamp = int(prepared.sequence_timestamps[position])
                    upper = min(
                        timestamp + horizon,
                        split_timestamp
                        if position <= last_training_target
                        else history_end,
                    )
                    outcome = int(np.searchsorted(timestamps, timestamp, side="left"))
                    if outcome < len(timestamps) and int(timestamps[outcome]) < upper:
                        weights[position] = config.organic_like_target_weight
                        grade_three += 1
            log(
                f"grade-3 first-encounter targets={grade_three:,} "
                f"horizon_days={config.discovery_horizon_days}"
            )
    log(
        f"target weighting={config.target_weighting} "
        f"min={weights.min():.3f} mean={weights.mean():.3f} "
        f"max={weights.max():.3f}"
    )
    return weights


def build_dense_block(
    prepared: SequenceData,
    target_weights: np.ndarray,
    users: np.ndarray,
    window_starts: np.ndarray,
    process_counts: np.ndarray,
    score_starts: np.ndarray,
    start: int,
    steps: int,
    config: Config,
) -> tuple[np.ndarray, ...]:
    """Build one causal sequence block and mark the target rows to score."""
    batch_size = len(users)
    padding_item = len(prepared.item_ids)
    input_items = np.full((batch_size, steps), padding_item, dtype=np.uint16)
    event_features = np.zeros((batch_size, steps, 3), dtype=np.float16)
    activity_features = np.zeros((batch_size, steps, 4), dtype=np.float16)
    state_ids = np.zeros((batch_size, steps), dtype=np.uint32)
    targets = np.zeros((batch_size, steps), dtype=np.uint16)
    weights = np.ones((batch_size, steps), dtype=np.float32)
    scored = np.zeros((batch_size, steps), dtype=bool)
    histories = np.full(
        (batch_size, steps, config.bptt_steps),
        padding_item,
        dtype=np.uint16,
    )
    processed = np.zeros(batch_size, dtype=np.int32)

    lengths = prepared.lengths
    for row, user_row in enumerate(users):
        count = min(steps, max(int(process_counts[row]) - start, 0))
        if not count:
            continue
        offset = int(prepared.offsets[user_row])
        window_start = int(window_starts[row])
        absolute_start = window_start + start
        positions = slice(
            offset + absolute_start,
            offset + absolute_start + count,
        )
        target_positions = slice(
            offset + absolute_start + 1,
            offset + absolute_start + count + 1,
        )
        input_items[row, :count] = prepared.sequence_items[positions]
        event_features[row, :count] = prepared.event_features[positions]
        activity_features[row, :count] = prepared.activity_features[positions]
        state_ids[row, :count] = prepared.state_ids[positions]
        targets[row, :count] = prepared.sequence_items[target_positions]
        weights[row, :count] = target_weights[target_positions]
        score_from = min(count, max(int(score_starts[row]) - start, 0))
        scored[row, score_from:count] = True
        processed[row] = count
        user_sequence = prepared.sequence_items[
            offset : offset + int(lengths[user_row])
        ]
        histories[row, :count] = history_windows(
            user_sequence,
            absolute_start,
            count,
            config.bptt_steps,
            padding_item,
        )
    return (
        input_items,
        event_features,
18

read_file train_current_model.py

+07:21
Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "file_path": "/app/solution/train_current_model.py",
  "end_line": 1350,
  "start_line": 1100
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 1100-1350 of 2165 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 1351.

--- FILE CONTENT (truncated) ---
        event_features,
        activity_features,
        state_ids,
        targets,
        scored,
        histories,
        processed,
        weights,
    )


def score_target_microbatches(
    model: base.SequentialTwoTower,
    prepared: SequenceData,
    config: Config,
    sequence_vectors: torch.Tensor,
    flat_states: np.ndarray,
    flat_activity: np.ndarray,
    positive_items: torch.Tensor,
    negatives: torch.Tensor,
    negative_weights: torch.Tensor,
    sample_weights: np.ndarray,
    device: torch.device,
    backward: bool,
) -> tuple[dict[str, float], torch.Tensor | None]:
    """Compute one logical block's exact BCE in bounded-memory slices."""
    target_count = len(positive_items)
    total_weight = float(sample_weights.sum())
    if total_weight <= 0:
        raise RuntimeError("target block has no positive sample weight")
    sequence_gradient = torch.zeros_like(sequence_vectors) if backward else None
    statistics = {
        "loss_sum": 0.0,
        "positive_sum": 0.0,
        "negative_sum": 0.0,
        "pair_correct": 0.0,
        "weight_sum": 0.0,
    }
    for begin in range(0, target_count, config.loss_microbatch_size):
        end = min(begin + config.loss_microbatch_size, target_count)
        selected_states = flat_states[begin:end]
        if backward:
            sequence_input = (
                sequence_vectors[begin:end].detach().requires_grad_(True)
            )
        else:
            sequence_input = sequence_vectors[begin:end]
        liked_vectors, disliked_vectors, _ = pool_explicit_states(
            model, prepared, selected_states, device
        )
        counts = prepared.state_counts[selected_states]
        numeric = np.zeros((end - begin, 6), dtype=np.float32)
        numeric[:, :4] = flat_activity[begin:end]
        numeric[:, 4] = np.log1p(counts[:, 0]) / 6.0
        numeric[:, 5] = np.log1p(counts[:, 1]) / 4.0
        query_vectors = user_queries(
            model,
            sequence_input,
            liked_vectors,
            disliked_vectors,
            torch.from_numpy(numeric).to(device),
        )
        positive_vectors, negative_vectors = candidate_vectors(
            model,
            positive_items[begin:end],
            negatives[begin:end],
        )
        positive_logits = (query_vectors * positive_vectors).sum(dim=1)
        negative_logits = torch.einsum(
            "bd,bkd->bk", query_vectors, negative_vectors
        )
        positive_loss = F.softplus(-positive_logits)
        negative_loss = corrected_negative_loss(
            negative_logits, negative_weights[begin:end], config
        )
        selected_weights = torch.from_numpy(
            sample_weights[begin:end].astype(np.float32, copy=False)
        ).to(device)
        loss_sum = (
            selected_weights * (positive_loss + negative_loss) / 2.0
        ).sum()
        if not bool(torch.isfinite(loss_sum)):
            raise RuntimeError("dense next-item training produced non-finite loss")
        if backward:
            (loss_sum / total_weight).backward()
            if sequence_input.grad is None:
                raise RuntimeError("sequence microbatch did not produce a gradient")
            sequence_gradient[begin:end] = sequence_input.grad
        statistics["loss_sum"] += float(loss_sum.detach().cpu())
        statistics["positive_sum"] += float(positive_logits.detach().sum().cpu())
        statistics["negative_sum"] += float(negative_logits.detach().sum().cpu())
        statistics["pair_correct"] += float(
            (positive_logits.detach()[:, None] > negative_logits.detach()).sum().cpu()
        )
        statistics["weight_sum"] += float(selected_weights.sum().detach().cpu())
    return statistics, sequence_gradient


def release_accelerator_cache(device: torch.device) -> None:
    if device.type == "mps":
        torch.mps.empty_cache()


def run_training_epoch(
    model: base.SequentialTwoTower,
    optimizer: torch.optim.Optimizer,
    prepared: SequenceData,
    config: Config,
    target_weights: np.ndarray,
    window_starts: np.ndarray,
    target_counts: np.ndarray,
    item_correction: torch.Tensor,
    known_positive_packed: np.ndarray | None,
    generator: torch.Generator,
    device: torch.device,
    epoch: int,
) -> dict[str, float]:
    model.train()
    train_users = np.flatnonzero(target_counts > 0)
    sorted_users = train_users[
        np.argsort(target_counts[train_users], kind="stable")
    ]
    groups = [
        sorted_users[start : start + config.user_batch_size]
        for start in range(0, len(sorted_users), config.user_batch_size)
    ]
    group_order = torch.randperm(len(groups), generator=generator).numpy()
    negative_count = config.uniform_negatives + config.inbatch_negatives
    total_loss = 0.0
    total_targets = 0
    total_weight = 0.0
    total_positive = 0.0
    total_negative = 0.0
    total_pair_correct = 0.0
    batches = 0
    started = time.monotonic()

    for group_number in group_order:
        users = groups[int(group_number)]
        group_counts = target_counts[users]
        hidden = torch.zeros(
            1, len(users), config.embedding_dim, device=device
        )
        max_targets = int(group_counts.max())
        for start in range(0, max_targets, config.bptt_steps):
            steps = min(config.bptt_steps, max_targets - start)
            block = build_dense_block(
                prepared,
                target_weights,
                users,
                window_starts[users],
                group_counts,
                np.zeros(len(users), dtype=np.int64),
                start,
                steps,
                config,
            )
            sequence_outputs, _ = event_sequence(
                model,
                torch.from_numpy(block[0].astype(np.int64)).to(device),
                torch.from_numpy(block[1].astype(np.float32)).to(device),
                hidden,
            )
            hidden = torch.stack(
                [
                    sequence_outputs[row, count - 1]
                    if count
                    else hidden[0, row]
                    for row, count in enumerate(block[7])
                ]
            ).unsqueeze(0).detach()
            flat_scored = block[5].reshape(-1)
            if not np.any(flat_scored):
                continue
            mask = torch.from_numpy(flat_scored).to(device)
            sequence_vectors = sequence_outputs.reshape(
                -1, config.embedding_dim
            )[mask]
            flat_states = block[3].reshape(-1)[flat_scored]
            positive_items = torch.from_numpy(
                block[4].reshape(-1)[flat_scored].astype(np.int64)
            ).to(device)
            known_history = torch.from_numpy(
                block[6].reshape(-1, config.bptt_steps)[flat_scored].astype(
                    np.int64
                )
            ).to(device)
            liked_items = torch.from_numpy(
                prepared.liked_states[flat_states].astype(np.int64)
            ).to(device)
            flat_user_rows = np.broadcast_to(
                users[:, None], block[5].shape
            ).reshape(-1)[flat_scored]
            negatives, negative_weights = draw_training_negatives(
                positive_items,
                known_history,
                liked_items,
                flat_user_rows,
                known_positive_packed,
                prepared,
                config,
                item_correction,
                generator,
                device,
            )
            optimizer.zero_grad(set_to_none=True)
            statistics, sequence_gradient = score_target_microbatches(
                model,
                prepared,
                config,
                sequence_vectors,
                flat_states,
                block[2].reshape(-1, 4)[flat_scored].astype(np.float32),
                positive_items,
                negatives,
                negative_weights,
                block[8].reshape(-1)[flat_scored],
                device,
                backward=True,
            )
            if sequence_gradient is None:
                raise RuntimeError("training block omitted its sequence gradient")
            sequence_vectors.backward(sequence_gradient)
            nn.utils.clip_grad_norm_(model.parameters(), config.gradient_clip)
            optimizer.step()

            count = len(positive_items)
            total_loss += statistics["loss_sum"]
            total_targets += count
            total_weight += statistics["weight_sum"]
            total_positive += statistics["positive_sum"]
            total_negative += statistics["negative_sum"]
            total_pair_correct += statistics["pair_correct"]
            batches += 1
            if batches % 25 == 0:
                release_accelerator_cache(device)
            if batches % 250 == 0:
                batch_bce = statistics["loss_sum"] / max(
                    statistics["weight_sum"], 1.0e-12
                )
                running_bce = total_loss / max(total_weight, 1.0e-12)
                log(
                    f"epoch={epoch}/{config.epochs} batches={batches:,} "
                    f"targets={total_targets:,} "
                    f"batch_bce={batch_bce:.6f} "
                    f"running_bce={running_bce:.6f} "
                    f"elapsed={time.monotonic() - started:.1f}s"
                )

    return {
        "epoch": float(epoch),
19

read_file two_tower_model.py

+07:23
Tool callread_file/app/solution/two_tower_model.py Returned

Tool call · Input

{
  "file_path": "/app/solution/two_tower_model.py",
  "start_line": 1,
  "end_line": 200
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 1-200 of 434 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 201.

--- FILE CONTENT (truncated) ---
"""Shared public-data primitives for the Yambda two-tower baseline."""
from __future__ import annotations

import sys
from dataclasses import dataclass
from pathlib import Path
from typing import Iterator

import numpy as np
import pandas as pd
import pyarrow.parquet as pq
import torch
from torch import nn


DAY = 86_400
TRAIN_END = 24_786_800
VALIDATION_END = 25_393_400
LISTEN_POSITIVE_THRESHOLD = 50
PROFILE_LOOKBACK_DAYS = 120
LIKE_ITEMS = 48
DISLIKE_ITEMS = 24
TOP_N = 100


@dataclass(frozen=True)
class TowerConfig:
    sequence_length: int = 100
    embedding_dim: int = 192
    hidden_dim: int = 192
    user_hidden_1: int = 512
    user_hidden_2: int = 256
    item_hidden_1: int = 512
    item_hidden_2: int = 256
    dropout: float = 0.05
    epochs: int = 1
    learning_rate: float = 1.0e-3
    weight_decay: float = 1.0e-5
    gradient_clip: float = 2.0
    uniform_negatives: int = 24
    inbatch_negatives: int = 8
    inbatch_correction_power: float = 0.5
    inbatch_correction_min: float = 0.25
    inbatch_correction_max: float = 4.0
    seed: int = 29


@dataclass(frozen=True)
class ListenEvents:
    timestamps: np.ndarray
    items: np.ndarray
    organic: np.ndarray
    completion_pct: np.ndarray


@dataclass(frozen=True)
class ExplicitEvents:
    timestamps: np.ndarray
    items: np.ndarray
    channel: np.ndarray
    active: np.ndarray
    organic_like: np.ndarray


def log(message: str) -> None:
    print(message, file=sys.stderr, flush=True)


def build_item_features(catalog: pd.DataFrame) -> np.ndarray:
    """Return four standardized features built only from the public catalog."""
    positives = catalog.positive_listens.to_numpy(dtype=np.float64, copy=False)
    organic = catalog.organic_positive_listens.to_numpy(dtype=np.float64, copy=False)
    popularity_rank = catalog.popularity_rank.to_numpy(dtype=np.float64, copy=False)
    features = np.column_stack(
        [
            np.log1p(positives),
            np.log1p(organic),
            organic / np.maximum(positives, 1.0),
            1.0 - (popularity_rank - 1.0) / max(len(catalog) - 1, 1),
        ]
    )
    means = features.mean(axis=0, keepdims=True)
    scales = np.maximum(features.std(axis=0, keepdims=True), 1.0e-6)
    standardized = ((features - means) / scales).astype(np.float32)
    if not np.isfinite(standardized).all():
        raise RuntimeError("catalog features contain non-finite values")
    return standardized


def _combine_listen_chunks(parts: list[ListenEvents]) -> ListenEvents:
    if len(parts) == 1:
        return parts[0]
    timestamps = np.concatenate([part.timestamps for part in parts])
    items = np.concatenate([part.items for part in parts])
    organic = np.concatenate([part.organic for part in parts])
    completion = np.concatenate([part.completion_pct for part in parts])
    order = np.argsort(timestamps, kind="stable")
    return ListenEvents(
        timestamps=timestamps[order],
        items=items[order],
        organic=organic[order],
        completion_pct=completion[order],
    )


def iter_listen_users(
    path: Path, item_index: pd.Index
) -> Iterator[tuple[int, ListenEvents]]:
    """Stream one uid-sorted public listen file one user at a time."""
    parquet = pq.ParquetFile(path)
    pending_uid: int | None = None
    pending: list[ListenEvents] = []
    previous_uid = -1
    for batch in parquet.iter_batches(
        batch_size=750_000,
        columns=["uid", "timestamp", "item_id", "is_organic", "played_ratio_pct"],
    ):
        frame = batch.to_pandas()
        mapped = item_index.get_indexer(frame.item_id.to_numpy(dtype=np.int64))
        keep = mapped >= 0
        if not np.any(keep):
            continue
        uids = frame.uid.to_numpy(dtype=np.int64, copy=False)[keep]
        timestamps = frame.timestamp.to_numpy(dtype=np.int64, copy=False)[keep]
        items = mapped[keep].astype(np.int32, copy=False)
        organic = frame.is_organic.to_numpy(dtype=np.uint8, copy=False)[keep]
        completion = frame.played_ratio_pct.to_numpy(dtype=np.uint16, copy=False)[keep]
        if np.any(uids[1:] < uids[:-1]):
            raise RuntimeError(f"{path.name} is not sorted by uid")
        boundaries = np.r_[
            0,
            np.flatnonzero(uids[1:] != uids[:-1]) + 1,
            len(uids),
        ]
        for start, end in zip(boundaries[:-1], boundaries[1:]):
            uid = int(uids[start])
            part = ListenEvents(
                timestamps[start:end].copy(),
                items[start:end].copy(),
                organic[start:end].copy(),
                completion[start:end].copy(),
            )
            if pending_uid is None:
                pending_uid = uid
            elif uid != pending_uid:
                if pending_uid < previous_uid:
                    raise RuntimeError(f"{path.name} user order regressed")
                yield pending_uid, _combine_listen_chunks(pending)
                previous_uid = pending_uid
                pending_uid = uid
                pending = []
            pending.append(part)
    if pending_uid is not None:
        yield pending_uid, _combine_listen_chunks(pending)


def merge_listen_streams(
    paths: list[Path], item_index: pd.Index
) -> Iterator[tuple[int, ListenEvents]]:
    """Merge uid-sorted public listen files without materializing them."""
    streams = [iter(iter_listen_users(path, item_index)) for path in paths]
    heads: list[tuple[int, ListenEvents] | None] = [
        next(stream, None) for stream in streams
    ]
    while any(head is not None for head in heads):
        uid = min(head[0] for head in heads if head is not None)
        parts: list[ListenEvents] = []
        for position, head in enumerate(heads):
            if head is not None and head[0] == uid:
                parts.append(head[1])
                heads[position] = next(streams[position], None)
        yield uid, _combine_listen_chunks(parts)


def load_explicit_events(
    data: Path,
    prefixes: tuple[str, ...],
    item_index: pd.Index,
) -> dict[int, ExplicitEvents]:
    """Load public explicit actions as chronological state changes."""
    specifications = (
        ("likes", 0, 1, 0),
        ("unlikes", 0, 0, 1),
        ("dislikes", 1, 1, 0),
        ("undislikes", 1, 0, 1),
    )
    parts: list[pd.DataFrame] = []
    for family, channel, active, tie_priority in specifications:
        for prefix in prefixes:
            frame = pd.read_parquet(
                data / f"{prefix}_{family}.parquet",
                columns=["uid", "timestamp", "item_id", "is_organic"],
            )
            mapped = item_index.get_indexer(
                frame.item_id.to_numpy(dtype=np.int64, copy=False)
            )
            keep = mapped >= 0
            if not np.any(keep):
                continue
            retained = frame.loc[keep, ["uid", "timestamp", "is_organic"]].copy()
20

read_file two_tower_model.py

+07:25
Tool callread_file/app/solution/two_tower_model.py Returned

Tool call · Input

{
  "file_path": "/app/solution/two_tower_model.py",
  "start_line": 201,
  "end_line": 434
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 201-434 of 434 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 435.

--- FILE CONTENT (truncated) ---
            retained["item"] = mapped[keep].astype(np.int32, copy=False)
            retained["channel"] = np.int8(channel)
            retained["active"] = np.int8(active)
            retained["tie_priority"] = np.int8(tie_priority)
            retained["organic_like"] = np.int8(
                family == "likes"
            ) * retained.is_organic.astype(np.int8)
            parts.append(retained.drop(columns="is_organic"))
    if not parts:
        return {}
    events = pd.concat(parts, ignore_index=True)
    events = events.sort_values(
        ["uid", "timestamp", "tie_priority"], kind="mergesort"
    ).reset_index(drop=True)
    result: dict[int, ExplicitEvents] = {}
    for uid, rows in events.groupby("uid", sort=False):
        result[int(uid)] = ExplicitEvents(
            timestamps=rows.timestamp.to_numpy(dtype=np.int64, copy=True),
            items=rows.item.to_numpy(dtype=np.int32, copy=True),
            channel=rows.channel.to_numpy(dtype=np.int8, copy=True),
            active=rows.active.to_numpy(dtype=np.int8, copy=True),
            organic_like=rows.organic_like.to_numpy(dtype=np.int8, copy=True),
        )
    log(f"loaded explicit events: rows={len(events):,} users={len(result):,}")
    return result


def empty_explicit_events() -> ExplicitEvents:
    return ExplicitEvents(
        timestamps=np.empty(0, dtype=np.int64),
        items=np.empty(0, dtype=np.int32),
        channel=np.empty(0, dtype=np.int8),
        active=np.empty(0, dtype=np.int8),
        organic_like=np.empty(0, dtype=np.int8),
    )


def pack_active_items(
    active: dict[int, int], width: int, padding_item: int
) -> np.ndarray:
    packed = np.full(width, padding_item, dtype=np.uint16)
    if not active:
        return packed
    ordered = sorted(active.items(), key=lambda pair: (-pair[1], pair[0]))[:width]
    packed[: len(ordered)] = np.fromiter(
        (item for item, _ in ordered), dtype=np.uint16, count=len(ordered)
    )
    return packed


def load_inference_state(
    path: Path,
    item_index: pd.Index,
    uids: np.ndarray,
    n_items: int,
) -> tuple[np.ndarray, np.ndarray, np.ndarray, np.ndarray]:
    """Pack the task-provided active explicit state."""
    state = pd.read_parquet(path, columns=["uid", "item_id", "state"])
    mapped = item_index.get_indexer(state.item_id.to_numpy(dtype=np.int64))
    keep = mapped >= 0
    state = state.loc[keep, ["uid", "state"]].copy()
    state["item"] = mapped[keep].astype(np.int32, copy=False)
    user_rows = pd.Index(uids)
    liked = np.full((len(uids), LIKE_ITEMS), n_items, dtype=np.uint16)
    disliked = np.full((len(uids), DISLIKE_ITEMS), n_items, dtype=np.uint16)
    like_counts = np.zeros(len(uids), dtype=np.int32)
    dislike_counts = np.zeros(len(uids), dtype=np.int32)
    for value, width, destination, counts in (
        ("liked", LIKE_ITEMS, liked, like_counts),
        ("disliked", DISLIKE_ITEMS, disliked, dislike_counts),
    ):
        selected = state[state.state == value]
        for uid, rows in selected.groupby("uid", sort=False):
            row = int(user_rows.get_indexer([int(uid)])[0])
            if row < 0:
                continue
            items = np.sort(rows.item.unique())
            counts[row] = len(items)
            retained = items[:width]
            destination[row, : len(retained)] = retained.astype(np.uint16)
    return liked, disliked, like_counts, dislike_counts


class SequentialTwoTower(nn.Module):
    """Order-sensitive user tower and independent catalog-aware item tower."""

    def __init__(self, item_features: np.ndarray, config: TowerConfig) -> None:
        super().__init__()
        n_items, n_item_features = item_features.shape
        dim = config.embedding_dim
        self.n_items = n_items
        self.context_embedding = nn.Embedding(
            n_items + 1, dim, padding_idx=n_items
        )
        self.event_projection = nn.Sequential(
            nn.Linear(dim + 3, config.hidden_dim),
            nn.GELU(),
        )
        self.sequence_encoder = nn.GRU(
            input_size=config.hidden_dim,
            hidden_size=dim,
            num_layers=1,
            batch_first=True,
        )
        self.user_tower = nn.Sequential(
            nn.Linear(dim * 3 + 6, config.user_hidden_1),
            nn.GELU(),
            nn.Dropout(config.dropout),
            nn.Linear(config.user_hidden_1, config.user_hidden_2),
            nn.GELU(),
            nn.Dropout(config.dropout),
            nn.Linear(config.user_hidden_2, dim),
        )
        self.candidate_embedding = nn.Embedding(n_items, dim)
        self.register_buffer(
            "item_features", torch.from_numpy(item_features), persistent=True
        )
        self.item_tower = nn.Sequential(
            nn.Linear(dim + n_item_features, config.item_hidden_1),
            nn.GELU(),
            nn.Dropout(config.dropout),
            nn.Linear(config.item_hidden_1, config.item_hidden_2),
            nn.GELU(),
            nn.Dropout(config.dropout),
            nn.Linear(config.item_hidden_2, dim),
        )
        nn.init.normal_(self.context_embedding.weight, std=0.02)
        nn.init.normal_(self.candidate_embedding.weight, std=0.02)
        with torch.no_grad():
            self.context_embedding.weight[n_items].zero_()

    def _mean_context_channel(self, items: torch.Tensor) -> torch.Tensor:
        mask = items.ne(self.n_items)
        vectors = self.context_embedding(items)
        return (vectors * mask.unsqueeze(-1)).sum(dim=1) / mask.sum(
            dim=1, keepdim=True
        ).clamp_min(1)

    def encode_items(self, items: torch.Tensor) -> torch.Tensor:
        inputs = torch.cat(
            [self.candidate_embedding(items), self.item_features[items]], dim=1
        )
        return self.item_tower(inputs)


def invalid_negative_mask(
    negatives: torch.Tensor,
    targets: torch.Tensor,
    context_items: torch.Tensor,
    liked_items: torch.Tensor,
) -> torch.Tensor:
    """Identify targets, known positives, active likes, and row duplicates."""
    invalid = negatives.eq(targets[:, None])
    invalid |= negatives[:, :, None].eq(context_items[:, None, :]).any(dim=2)
    invalid |= negatives[:, :, None].eq(liked_items[:, None, :]).any(dim=2)
    for column in range(1, negatives.shape[1]):
        invalid[:, column] |= negatives[:, column, None].eq(
            negatives[:, :column]
        ).any(dim=1)
    return invalid


def draw_filtered_mixed_negatives(
    targets: torch.Tensor,
    context_items: torch.Tensor,
    liked_items: torch.Tensor,
    n_items: int,
    uniform_count: int,
    inbatch_count: int,
    item_correction: torch.Tensor,
    generator: torch.Generator,
    device: torch.device,
) -> tuple[torch.Tensor, torch.Tensor]:
    """Draw uniform and unique-target in-batch negatives."""
    batch_size = len(targets)
    uniform = torch.randint(
        n_items,
        (batch_size, uniform_count),
        generator=generator,
        device="cpu",
    )
    inbatch = torch.empty((batch_size, 0), dtype=torch.long, device="cpu")
    corrected_count = 0
    if inbatch_count:
        unique_targets = torch.unique(targets.detach().cpu())
        corrected_count = min(inbatch_count, max(len(unique_targets) - 1, 0))
        if corrected_count:
            priorities = torch.rand(
                (batch_size, len(unique_targets)), generator=generator
            )
            priorities.masked_fill_(
                unique_targets[None, :].eq(targets.detach().cpu()[:, None]),
                -1.0,
            )
            columns = torch.topk(priorities, k=corrected_count, dim=1).indices
            inbatch = unique_targets[columns]
        if corrected_count < inbatch_count:
            filler = torch.randint(
                n_items,
                (batch_size, inbatch_count - corrected_count),
                generator=generator,
                device="cpu",
            )
            inbatch = torch.cat([inbatch, filler], dim=1)

    negatives_cpu = torch.cat([uniform, inbatch], dim=1)
    correction_cpu = torch.ones_like(negatives_cpu, dtype=torch.float32)
    if corrected_count:
        correction_cpu[
            :, uniform_count : uniform_count + corrected_count
        ] = item_correction[inbatch[:, :corrected_count]]
    negatives = negatives_cpu.to(device)
    correction = correction_cpu.to(device)
    for _ in range(32):
        invalid = invalid_negative_mask(
            negatives, targets, context_items, liked_items
        )
        if not bool(invalid.any()):
            return negatives, correction
        replacements = torch.randint(
            n_items,
            (int(invalid.sum().detach().cpu()),),
            generator=generator,
            device="cpu",
        ).to(device)
        negatives[invalid] = replacements
        correction[invalid] = 1.0
    invalid = invalid_negative_mask(
        negatives, targets, context_items, liked_items
    )
    if bool(invalid.any()):
        raise RuntimeError("mixed negative resampling failed false-negative filter")
    return negatives, correction
21

grep_search command

+07:38
Recorded reasoning summary 39 words

Analyzing Latency Budget

I'm currently dissecting the prompt's constraints, specifically the strict request-time latency budget. My focus is on understanding how the precomputation of item vectors offline and the on-the-fly computation of user vectors impacts this crucial performance metric.

Recorded reasoning summary 59 words

Improving Negative Sampling

My current focus is on refining the negative sampling strategy within the training objective. I'm analyzing how the trainer selects and utilizes these examples, diagnosing existing limitations, and aiming to enhance the process within the fixed CPU budget. I will investigate the loss function, in-batch versus uniform negatives, and various negative weighting techniques to optimize performance.

Recorded reasoning summary 51 words

Clarifying Training Objective

I'm currently investigating the specific training objective as defined in train_current_model.py. My immediate goal is to ascertain whether modifying the loss function falls within the scope of the existing objective or requires a broader re-evaluation of the training setup. I am examining the architecture summary for key details.

Recorded reasoning summary 38 words

Investigating Loss Calculation

I'm currently examining the corrected_negative_loss function around lines 840-865 and its interplay with BCE loss. I'm also cross-referencing this with score_target_microbatches, specifically how positive_logits and negative_logits are computed to understand the full loss calculation process.

Recorded reasoning summary 46 words

Refining Loss Computation

I'm currently examining the exact calculation within corrected_negative_loss. It appears F.softplus(-positive_logits) is equivalent to BCE loss for label 1, and softplus(negative_logits) is BCE loss for label 0. I need to understand how negative_loss is averaged and combined here, particularly when uniform_negatives is considered.

Tool callgrep_searchTool call Returned

Tool call · Input

{
  "include_pattern": "train_current_model.py",
  "pattern": "add_argument",
  "dir_path": "/app/solution"
}

Tool response

Found 27 matches for pattern "add_argument" in path "/app/solution" (filter: "train_current_model.py"):
---
File: train_current_model.py
L1924:     parser.add_argument(
L1927:     parser.add_argument("--output", type=Path, required=True)
L1928:     parser.add_argument("--public-dir", type=Path, required=True)
L1929:     parser.add_argument("--prepared-cache", type=Path)
L1930:     parser.add_argument("--device", choices=("cpu", "mps"), default="cpu")
L1931:     parser.add_argument("--threads", type=int, default=8)
L1932:     parser.add_argument("--bptt-steps", type=int, default=Config.bptt_steps)
L1933:     parser.add_argument(
L1936:     parser.add_argument("--epochs", type=int, default=Config.epochs)
L1937:     parser.add_argument("--learning-rate", type=float, default=Config.learning_rate)
L1938:     parser.add_argument(
L1943:     parser.add_argument(
L1948:     parser.add_argument(
L1953:     parser.add_argument(
L1958:     parser.add_argument(
L1963:     parser.add_argument(
L1968:     parser.add_argument(
L1973:     parser.add_argument(
L1978:     parser.add_argument(
L1984:     parser.add_argument(
L1990:     parser.add_argument(
L1995:     parser.add_argument(
L2000:     parser.add_argument("--checkpoint-dir", type=Path)
L2001:     parser.add_argument("--resume-checkpoint", type=Path)
L2002:     parser.add_argument("--seed", type=int, default=Config.seed)
L2003:     parser.add_argument("--ranking-batch-size", type=int, default=64)
L2004:     parser.add_argument("--prepare-only", action="store_true")
---
22

read_file train_current_model.py

+07:44
Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "file_path": "/app/solution/train_current_model.py",
  "start_line": 1920,
  "end_line": 2015
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 1920-2015 of 2165 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 2016.

--- FILE CONTENT (truncated) ---


def main() -> int:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument(
        "--stage", choices=("validation", "submission"), default="validation"
    )
    parser.add_argument("--output", type=Path, required=True)
    parser.add_argument("--public-dir", type=Path, required=True)
    parser.add_argument("--prepared-cache", type=Path)
    parser.add_argument("--device", choices=("cpu", "mps"), default="cpu")
    parser.add_argument("--threads", type=int, default=8)
    parser.add_argument("--bptt-steps", type=int, default=Config.bptt_steps)
    parser.add_argument(
        "--user-batch-size", type=int, default=Config.user_batch_size
    )
    parser.add_argument("--epochs", type=int, default=Config.epochs)
    parser.add_argument("--learning-rate", type=float, default=Config.learning_rate)
    parser.add_argument(
        "--loss-microbatch-size",
        type=int,
        default=Config.loss_microbatch_size,
    )
    parser.add_argument(
        "--negative-filter-scope",
        choices=("full-training-history", "last-100"),
        default=Config.negative_filter_scope,
    )
    parser.add_argument(
        "--target-weighting",
        choices=("discovery-graded", "organic-strong", "uniform"),
        default=Config.target_weighting,
    )
    parser.add_argument(
        "--ordinary-target-weight",
        type=float,
        default=Config.ordinary_target_weight,
    )
    parser.add_argument(
        "--organic-strong-target-weight",
        type=float,
        default=Config.organic_strong_target_weight,
    )
    parser.add_argument(
        "--organic-like-target-weight",
        type=float,
        default=Config.organic_like_target_weight,
    )
    parser.add_argument(
        "--discovery-horizon-days",
        type=int,
        default=Config.discovery_horizon_days,
    )
    parser.add_argument(
        "--validation-fraction",
        type=float,
        default=Config.validation_fraction,
    )
    parser.add_argument(
        "--max-train-targets-per-user",
        type=int,
        default=Config.max_train_targets_per_user,
        help="retain this many recent pre-validation targets per user; 0 is uncapped",
    )
    parser.add_argument(
        "--max-validation-targets-per-user",
        type=int,
        default=Config.max_validation_targets_per_user,
        help="retain this many final validation targets per user; 0 is uncapped",
    )
    parser.add_argument(
        "--early-stopping-patience",
        type=int,
        default=Config.early_stopping_patience,
    )
    parser.add_argument(
        "--early-stopping-min-delta",
        type=float,
        default=Config.early_stopping_min_delta,
    )
    parser.add_argument("--checkpoint-dir", type=Path)
    parser.add_argument("--resume-checkpoint", type=Path)
    parser.add_argument("--seed", type=int, default=Config.seed)
    parser.add_argument("--ranking-batch-size", type=int, default=64)
    parser.add_argument("--prepare-only", action="store_true")
    args = parser.parse_args()

    if args.threads < 1 or args.bptt_steps < 2 or args.user_batch_size < 1:
        parser.error("threads, BPTT steps, and user batch size must be positive")
    if (
        args.epochs < 1
        or args.learning_rate <= 0
        or args.loss_microbatch_size < 1
        or args.early_stopping_patience < 1
        or args.early_stopping_min_delta < 0
        or args.ordinary_target_weight <= 0
23

read_file train_current_model.py

+07:58
Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "start_line": 2016,
  "file_path": "/app/solution/train_current_model.py",
  "end_line": 2160
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 2016-2160 of 2165 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 2161.

--- FILE CONTENT (truncated) ---
        or args.organic_strong_target_weight <= 0
        or args.organic_like_target_weight <= 0
        or args.discovery_horizon_days < 1
        or args.max_train_targets_per_user < 0
        or args.max_validation_targets_per_user < 0
    ):
        parser.error("training counts, learning rate, and patience are invalid")
    if not 0.0 < args.validation_fraction < 1.0:
        parser.error("validation fraction must be strictly between zero and one")
    public = args.public_dir.resolve()
    if not (public / "data" / "candidate_catalog.parquet").is_file():
        parser.error(f"public task data not found under {public}")
    config = Config(
        bptt_steps=args.bptt_steps,
        user_batch_size=args.user_batch_size,
        epochs=args.epochs,
        learning_rate=args.learning_rate,
        loss_microbatch_size=args.loss_microbatch_size,
        negative_filter_scope=args.negative_filter_scope,
        target_weighting=args.target_weighting,
        ordinary_target_weight=args.ordinary_target_weight,
        organic_strong_target_weight=args.organic_strong_target_weight,
        organic_like_target_weight=args.organic_like_target_weight,
        discovery_horizon_days=args.discovery_horizon_days,
        validation_fraction=args.validation_fraction,
        max_train_targets_per_user=args.max_train_targets_per_user,
        max_validation_targets_per_user=args.max_validation_targets_per_user,
        early_stopping_patience=args.early_stopping_patience,
        early_stopping_min_delta=args.early_stopping_min_delta,
        seed=args.seed,
    )
    torch.set_num_threads(args.threads)
    torch.set_num_interop_threads(1)
    seed_everything(config.seed)
    device = torch.device(args.device)
    if device.type == "mps" and not torch.backends.mps.is_available():
        parser.error("MPS was requested but is unavailable")

    started = time.monotonic()
    prepared, eligibility = load_or_prepare(
        public,
        args.stage,
        config,
        args.prepared_cache.resolve() if args.prepared_cache else None,
    )
    target_partition = chronological_target_partition(
        prepared,
        config.validation_fraction,
        config.max_train_targets_per_user,
        config.max_validation_targets_per_user,
    )
    if args.prepare_only:
        print(
            json.dumps(
                {
                    "stage": args.stage,
                    "sequence_users": len(prepared.user_ids),
                    "sequence_tokens": len(prepared.sequence_items),
                    "next_item_targets": prepared.target_count,
                    "selected_training_targets": int(
                        target_partition.training_counts.sum()
                    ),
                    "selected_validation_targets": int(
                        target_partition.validation_counts.sum()
                    ),
                    "discarded_old_targets": int(
                        target_partition.window_starts.sum()
                    ),
                    "target_users": len(eligibility.uids),
                    "runtime_seconds": round(time.monotonic() - started, 3),
                    "config": asdict(config),
                },
                indent=2,
            )
        )
        return 0

    model, training_history = train_model(
        public,
        args.stage,
        prepared,
        config,
        device,
        args.checkpoint_dir.resolve() if args.checkpoint_dir else None,
        args.resume_checkpoint.resolve() if args.resume_checkpoint else None,
    )
    ranking, embedding_diagnostics = rank_candidates(
        model,
        prepared,
        eligibility,
        config,
        device,
        args.ranking_batch_size,
    )
    write_ranking(ranking, args.output.resolve())
    print(
        json.dumps(
            {
                "baseline": "yambda-windowed-sequence-two-tower-base",
                "stage": args.stage,
                "output": str(args.output.resolve()),
                "rows": len(ranking),
                "users": int(ranking.uid.nunique()),
                "runtime_seconds": round(time.monotonic() - started, 3),
                "public_inputs_only": True,
                "architecture": {
                    "family": "pure-windowed-sequence-two-tower",
                    "sequence_training": (
                        "every-adjacent-target-within-recent-chronological-window"
                    ),
                    "sequence_encoder": "one-layer-GRU-dense-timestep-loss",
                    "bptt_hidden_state": "carried-and-detached",
                    "model_selection": "chronological-validation-BCE-early-stopping",
                    "loss_execution": "gradient-accumulated-microbatches",
                    "user_id_embedding": False,
                    "user_mlp": "582-512-256-192",
                    "item_mlp": "196-512-256-192",
                    "normalization": "none",
                    "score": "raw-dot-product",
                    "objective": "sample-weighted-BCE-at-every-timestep",
                    "negative_sampling": (
                        "24-uniform-plus-8-propensity-corrected-inbatch"
                    ),
                    "false_negative_filter": config.negative_filter_scope,
                    "target_weighting": config.target_weighting,
                },
                "config": asdict(config),
                "sequence_tokens": len(prepared.sequence_items),
                "all_next_item_targets": prepared.target_count,
                "selected_training_targets": int(
                    target_partition.training_counts.sum()
                ),
                "selected_validation_targets": int(
                    target_partition.validation_counts.sum()
                ),
                "discarded_old_targets": int(target_partition.window_starts.sum()),
                "training_history": training_history,
                "embedding_diagnostics": embedding_diagnostics,
                "torch_version": torch.__version__,
                "device": str(device),
            },
            indent=2,
        )
    )
    return 0
24

read_file train_current_model.py

+08:01
Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "end_line": 535,
  "start_line": 470,
  "file_path": "/app/solution/train_current_model.py"
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 470-535 of 2165 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 536.

--- FILE CONTENT (truncated) ---

def cache_metadata(stage: str, config: Config) -> dict[str, object]:
    return {
        "cache_version": CACHE_VERSION,
        "stage": stage,
        "positive_listen_threshold": base.LISTEN_POSITIVE_THRESHOLD,
        "profile_lookback_days": base.PROFILE_LOOKBACK_DAYS,
        "event_time_feature": "exp-negative-gap-over-60-days",
    }


def save_cache(
    path: Path, prepared: SequenceData, stage: str, config: Config
) -> None:
    path.parent.mkdir(parents=True, exist_ok=True)
    np.savez(
        path,
        metadata=np.asarray(json.dumps(cache_metadata(stage, config), sort_keys=True)),
        **prepared.__dict__,
    )
    log(f"saved public-derived full-sequence cache: {path}")


def load_cache(path: Path, stage: str, config: Config) -> SequenceData:
    with np.load(path, allow_pickle=False) as artifact:
        actual = json.loads(str(artifact["metadata"].item()))
        expected = cache_metadata(stage, config)
        if actual != expected:
            raise RuntimeError(f"sequence cache differs: {actual} != {expected}")
        values = {
            field: artifact[field].copy()
            for field in SequenceData.__dataclass_fields__
        }
    prepared = SequenceData(**values)
    log(
        f"loaded full-sequence cache: tokens={len(prepared.sequence_items):,} "
        f"targets={prepared.target_count:,}"
    )
    return prepared


def load_or_prepare(
    public: Path,
    stage: str,
    config: Config,
    cache: Path | None,
) -> tuple[SequenceData, CandidateSet]:
    candidate_name = (
        "validation_eligible_candidates.npz"
        if stage == "validation"
        else "test_eligible_candidates.npz"
    )
    eligibility = CandidateSet.read(public / "data" / candidate_name)
    if cache is not None and cache.is_file():
        prepared = load_cache(cache, stage, config)
        if not np.array_equal(prepared.item_ids, eligibility.item_ids):
            raise RuntimeError("cached catalog differs from candidate artifact")
        return prepared, eligibility
    prepared, built_eligibility = prepare_data(public, stage, config)
    if cache is not None:
        save_cache(cache, prepared, stage, config)
    return prepared, built_eligibility


def build_item_correction(
    prepared: SequenceData,
25

Check available disk space

+08:04
Recorded reasoning summary 44 words

Caching Data Preparation

I've implemented caching for data preparation, allowing me to load pre-processed data using --prepared-cache. This significantly speeds things up, as evidenced by the recent validation run, which previously took about 50 seconds to process over 9,000 users and 20 million tokens.

Tool callrun_shell_commandCheck available disk space Returned

Tool call · Input

{
  "description": "Check available disk space",
  "command": "df -h"
}

Tool response

<untrusted_context>
Output: Filesystem      Size  Used Avail Use% Mounted on
overlay          96G   14G   83G  15% /
tmpfs            64M     0   64M   0% /dev
shm              64M     0   64M   0% /dev/shm
/dev/root        96G   14G   83G  15% /etc/hosts
tmpfs           7.7G     0  7.7G   0% /proc/acpi
tmpfs           7.7G     0  7.7G   0% /proc/scsi
tmpfs           7.7G     0  7.7G   0% /sys/firmware
Process Group PGID: 1692
</untrusted_context>
26

Prepare and cache validation sequence data

+08:07
Recorded reasoning summary 36 words

Preparing Validation Cache

I'm focusing on optimizing our iteration speed. To achieve this, I'm preparing and saving the validation cache. The plan is to run a specific script to ensure this crucial step is completed efficiently.

Tool callrun_shell_commandPrepare and cache validation sequence data Returned

Tool call · Input

{
  "description": "Prepare and cache validation sequence data",
  "command": "python /app/solution/train_current_model.py \\\n  --stage validation \\\n  --public-dir /task \\\n  --prepared-cache /app/solution/prepared_val.npz \\\n  --prepare-only"
}

Tool response

<untrusted_context>
Output: usage: train_current_model.py [-h] [--stage {validation,submission}] --output
                              OUTPUT --public-dir PUBLIC_DIR
                              [--prepared-cache PREPARED_CACHE]
                              [--device {cpu,mps}] [--threads THREADS]
                              [--bptt-steps BPTT_STEPS]
                              [--user-batch-size USER_BATCH_SIZE]
                              [--epochs EPOCHS]
                              [--learning-rate LEARNING_RATE]
                              [--loss-microbatch-size LOSS_MICROBATCH_SIZE]
                              [--negative-filter-scope {full-training-history,last-100}]
                              [--target-weighting {discovery-graded,organic-strong,uniform}]
                              [--ordinary-target-weight ORDINARY_TARGET_WEIGHT]
                              [--organic-strong-target-weight ORGANIC_STRONG_TARGET_WEIGHT]
                              [--organic-like-target-weight ORGANIC_LIKE_TARGET_WEIGHT]
                              [--discovery-horizon-days DISCOVERY_HORIZON_DAYS]
                              [--validation-fraction VALIDATION_FRACTION]
                              [--max-train-targets-per-user MAX_TRAIN_TARGETS_PER_USER]
                              [--max-validation-targets-per-user MAX_VALIDATION_TARGETS_PER_USER]
                              [--early-stopping-patience EARLY_STOPPING_PATIENCE]
                              [--early-stopping-min-delta EARLY_STOPPING_MIN_DELTA]
                              [--checkpoint-dir CHECKPOINT_DIR]
                              [--resume-checkpoint RESUME_CHECKPOINT]
                              [--seed SEED]
                              [--ranking-batch-size RANKING_BATCH_SIZE]
                              [--prepare-only]
train_current_model.py: error: the following arguments are required: --output
Exit Code: 2
Process Group PGID: 1695
</untrusted_context>
27

Build validation cache

+08:13
Tool callrun_shell_commandBuild validation cache Returned

Tool call · Input

{
  "description": "Build validation cache",
  "command": "python /app/solution/train_current_model.py \\\n  --stage validation \\\n  --public-dir /task \\\n  --prepared-cache /app/solution/prepared_val.npz \\\n  --output /app/solution/dummy.parquet \\\n  --prepare-only"
}

Tool response

<untrusted_context>
Output: loaded explicit events: rows=720,270 users=8,220
prepared users=1,000 tokens=2,090,746 states=35,727 elapsed=4.8s
prepared users=2,000 tokens=4,301,266 states=71,242 elapsed=9.8s
prepared users=3,000 tokens=6,486,146 states=109,471 elapsed=14.9s
prepared users=4,000 tokens=8,793,043 states=148,210 elapsed=20.3s
prepared users=5,000 tokens=10,992,205 states=182,596 elapsed=25.1s
prepared users=6,000 tokens=13,061,727 states=217,148 elapsed=29.8s
prepared users=7,000 tokens=15,334,418 states=256,914 elapsed=35.3s
prepared users=8,000 tokens=17,462,672 states=296,703 elapsed=40.5s
prepared users=9,000 tokens=19,568,405 states=331,551 elapsed=45.2s
target users without qualifying catalog sequence=7
prepared stage=validation sequence_users=9,135 tokens=20,056,329 next_item_targets=20,047,194 states=339,133
saved public-derived full-sequence cache: /app/solution/prepared_val.npz
{
  "stage": "validation",
  "sequence_users": 9135,
  "sequence_tokens": 20056329,
  "next_item_targets": 20047194,
  "selected_training_targets": 1052953,
  "selected_validation_targets": 130103,
  "discarded_old_targets": 18864138,
  "target_users": 8456,
  "runtime_seconds": 50.384,
  "config": {
    "bptt_steps": 100,
    "user_batch_size": 64,
    "embedding_dim": 192,
    "hidden_dim": 192,
    "user_hidden_1": 512,
    "user_hidden_2": 256,
    "item_hidden_1": 512,
    "item_hidden_2": 256,
    "dropout": 0.05,
    "epochs": 1,
    "learning_rate": 0.001,
    "weight_decay": 1e-05,
    "gradient_clip": 2.0,
    "loss_microbatch_size": 65536,
    "uniform_negatives": 24,
    "inbatch_negatives": 8,
    "inbatch_correction_power": 0.5,
    "inbatch_correction_min": 0.25,
    "inbatch_correction_max": 4.0,
    "negative_filter_scope": "full-training-history",
    "target_weighting": "organic-strong",
    "ordinary_target_weight": 0.25,
    "organic_strong_target_weight": 1.0,
    "organic_like_target_weight": 3.0,
    "discovery_horizon_days": 7,
    "validation_fraction": 0.1,
    "max_train_targets_per_user": 128,
    "max_validation_targets_per_user": 16,
    "early_stopping_patience": 1,
    "early_stopping_min_delta": 0.0001,
    "seed": 29
  }
}
Process Group PGID: 1706
</untrusted_context>
28

Check prepared_val.npz size

+09:10
Tool callrun_shell_commandCheck prepared_val.npz size Returned

Tool call · Input

{
  "command": "ls -lh /app/solution/prepared_val.npz",
  "description": "Check prepared_val.npz size"
}

Tool response

<untrusted_context>
Output: -rw-r--r-- 1 agent agent 511M Sep 29 01:30 /app/solution/prepared_val.npz
Process Group PGID: 1733
</untrusted_context>
29

read_file train_current_model.py

+09:14
Recorded reasoning summary 52 words

Optimizing Loading and Submission

I've significantly sped up the NPZ loading process, reducing it from 50 seconds to just 1. To ensure we always have a valid submission, I'm also implementing immediate generation of a baseline submission file as per the prompt's requirement to maintain the best valid submission throughout the attempt.

Recorded reasoning summary 48 words

Validating Submission Logic

I'm now investigating the performance characteristics of the --stage submission command to understand its execution time. My current thought is to adapt train_current_model.py to leverage this stage, noting that it will train on combined train and validation data, a factor I need to account for.

Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "start_line": 1850,
  "file_path": "/app/solution/train_current_model.py",
  "end_line": 1925
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 1850-1925 of 2165 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 1926.

--- FILE CONTENT (truncated) ---
            model._mean_context_channel(liked_items),
            model._mean_context_channel(disliked_items),
            torch.from_numpy(
                prepared.inference_user_features[output_rows].astype(np.float32)
            ).to(device),
        )
        result[torch.from_numpy(output_rows.astype(np.int64))] = queries.cpu()
    return result


@torch.inference_mode()
def rank_candidates(
    model: base.SequentialTwoTower,
    prepared: SequenceData,
    eligibility: CandidateSet,
    config: Config,
    device: torch.device,
    ranking_batch_size: int,
) -> tuple[pd.DataFrame, dict[str, float]]:
    model.eval()
    queries = inference_queries(model, prepared, config, device)
    item_parts: list[torch.Tensor] = []
    for start in range(0, len(prepared.item_ids), 2_048):
        rows = torch.arange(
            start,
            min(start + 2_048, len(prepared.item_ids)),
            dtype=torch.long,
            device=device,
        )
        item_parts.append(model.encode_items(rows).cpu())
    items = torch.cat(item_parts)
    rows: list[tuple[int, int, int]] = []
    for start in range(0, len(eligibility.uids), ranking_batch_size):
        end = min(start + ranking_batch_size, len(eligibility.uids))
        scores = queries[start:end] @ items.T
        eligible = np.unpackbits(
            eligibility.packed[start:end],
            axis=1,
            count=len(prepared.item_ids),
            bitorder="little",
        ).astype(bool, copy=False)
        scores.masked_fill_(~torch.from_numpy(eligible), -torch.inf)
        selected = torch.topk(scores, k=base.TOP_N, dim=1).indices.numpy()
        for local_row, columns in enumerate(selected):
            uid = int(eligibility.uids[start + local_row])
            rows.extend(
                (uid, int(prepared.item_ids[column]), rank)
                for rank, column in enumerate(columns, start=1)
            )
        if end == len(eligibility.uids) or end % 1_024 == 0:
            log(f"ranked users={end:,}/{len(eligibility.uids):,}")
    query_norm = torch.linalg.vector_norm(queries, dim=1).numpy()
    item_norm = torch.linalg.vector_norm(items, dim=1).numpy()
    diagnostics = {
        "query_norm_mean": float(query_norm.mean()),
        "query_norm_std": float(query_norm.std()),
        "item_norm_mean": float(item_norm.mean()),
        "item_norm_std": float(item_norm.std()),
    }
    return pd.DataFrame(rows, columns=["uid", "item_id", "rank"]), diagnostics


def write_ranking(frame: pd.DataFrame, output: Path) -> None:
    output.parent.mkdir(parents=True, exist_ok=True)
    if output.suffix == ".parquet":
        frame.to_parquet(output, index=False, compression="zstd")
    elif output.suffix == ".csv":
        frame.to_csv(output, index=False)
    else:
        raise ValueError("--output must end in .parquet or .csv")


def main() -> int:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument(
        "--stage", choices=("validation", "submission"), default="validation"
30

read_file train_current_model.py

+09:20
Recorded reasoning summary 33 words

Analyzing Candidate Ranking

I'm currently examining the rank_candidates function, specifically the matrix multiplication for scores and the unpacking of eligibility bits. My focus is on how these operations interact to determine candidate rankings.

Recorded reasoning summary 40 words

Investigating Baseline Performance

I'm now dissecting how the masked_fill operation impacts candidate scores before top-k selection. This step seems crucial for understanding the initial filtering before ranking. I'm also noting the DataFrame creation and the specific requirement for submission stages.

Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "end_line": 760,
  "start_line": 570,
  "file_path": "/app/solution/train_current_model.py"
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 570-760 of 2165 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 761.

--- FILE CONTENT (truncated) ---
    mean_on_targets = float(np.sum(counts * correction) / max(total, 1.0))
    log(
        f"inbatch correction: min={correction.min():.3f} "
        f"mean_on_targets={mean_on_targets:.3f} max={correction.max():.3f}"
    )
    return torch.from_numpy(correction)


def build_known_positive_filter(
    prepared: SequenceData, training_counts: np.ndarray
) -> np.ndarray:
    """Pack each user's complete public-training positive-item set."""
    width = (len(prepared.item_ids) + 7) // 8
    packed = np.zeros((len(prepared.user_ids), width), dtype=np.uint8)
    retained = 0
    for user_row, target_count in enumerate(training_counts):
        if not target_count:
            continue
        offset = int(prepared.offsets[user_row])
        # T adjacent targets consume sequence positions 0 through T.  The
        # chronological BCE suffix starts at T + 1 and is intentionally absent.
        items = np.unique(
            prepared.sequence_items[
                offset : offset + int(target_count) + 1
            ].astype(np.int64)
        )
        byte_columns = items >> 3
        bit_values = np.left_shift(
            np.uint8(1), (items & 7).astype(np.uint8)
        )
        np.bitwise_or.at(packed[user_row], byte_columns, bit_values)
        retained += len(items)
    log(
        f"full-history false-negative filter: users={len(prepared.user_ids):,} "
        f"unique_user_items={retained:,} bytes={packed.nbytes:,}"
    )
    return packed


def invalid_full_history_negatives(
    negatives: np.ndarray,
    targets: np.ndarray,
    user_rows: np.ndarray,
    known_positive_packed: np.ndarray,
    liked_items: np.ndarray,
) -> np.ndarray:
    """Return row-level invalid negatives using the complete training prefix."""
    byte_columns = negatives >> 3
    bit_columns = negatives & 7
    known = known_positive_packed[user_rows[:, None], byte_columns]
    invalid = ((known >> bit_columns) & 1).astype(bool)
    invalid |= negatives == targets[:, None]
    invalid |= (negatives[:, :, None] == liked_items[:, None, :]).any(axis=2)
    for column in range(1, negatives.shape[1]):
        invalid[:, column] |= (
            negatives[:, column, None] == negatives[:, :column]
        ).any(axis=1)
    return invalid


def draw_full_history_filtered_negatives(
    targets: torch.Tensor,
    user_rows: np.ndarray,
    liked_items: torch.Tensor,
    known_positive_packed: np.ndarray,
    n_items: int,
    config: Config,
    item_correction: torch.Tensor,
    generator: torch.Generator,
    device: torch.device,
) -> tuple[torch.Tensor, torch.Tensor]:
    """Draw mixed negatives and reject all known public-training positives."""
    targets_cpu = targets.detach().cpu().numpy().astype(np.int64, copy=False)
    liked_cpu = liked_items.detach().cpu().numpy().astype(np.int64, copy=False)
    batch_size = len(targets_cpu)
    uniform = torch.randint(
        n_items,
        (batch_size, config.uniform_negatives),
        generator=generator,
        device="cpu",
    )
    inbatch = torch.empty((batch_size, 0), dtype=torch.long)
    corrected_count = 0
    if config.inbatch_negatives:
        unique_targets = torch.unique(targets.detach().cpu())
        corrected_count = min(
            config.inbatch_negatives, max(len(unique_targets) - 1, 0)
        )
        if corrected_count:
            priorities = torch.rand(
                (batch_size, len(unique_targets)), generator=generator
            )
            priorities.masked_fill_(
                unique_targets[None, :].eq(
                    torch.from_numpy(targets_cpu)[:, None]
                ),
                -1.0,
            )
            columns = torch.topk(
                priorities, k=corrected_count, dim=1
            ).indices
            inbatch = unique_targets[columns]
        if corrected_count < config.inbatch_negatives:
            filler = torch.randint(
                n_items,
                (batch_size, config.inbatch_negatives - corrected_count),
                generator=generator,
                device="cpu",
            )
            inbatch = torch.cat([inbatch, filler], dim=1)

    negatives = torch.cat([uniform, inbatch], dim=1).numpy()
    correction = np.ones_like(negatives, dtype=np.float32)
    if corrected_count:
        correction[
            :, config.uniform_negatives : config.uniform_negatives + corrected_count
        ] = item_correction[inbatch[:, :corrected_count]].numpy()
    for _ in range(32):
        invalid = invalid_full_history_negatives(
            negatives,
            targets_cpu,
            user_rows,
            known_positive_packed,
            liked_cpu,
        )
        if not np.any(invalid):
            return (
                torch.from_numpy(negatives).to(device),
                torch.from_numpy(correction).to(device),
            )
        replacements = torch.randint(
            n_items,
            (int(invalid.sum()),),
            generator=generator,
            device="cpu",
        ).numpy()
        negatives[invalid] = replacements
        # Rejected in-batch items become ordinary uniform draws.
        correction[invalid] = 1.0
    invalid = invalid_full_history_negatives(
        negatives,
        targets_cpu,
        user_rows,
        known_positive_packed,
        liked_cpu,
    )
    if np.any(invalid):
        raise RuntimeError("full-history negative resampling failed")
    return (
        torch.from_numpy(negatives).to(device),
        torch.from_numpy(correction).to(device),
    )


def draw_training_negatives(
    positive_items: torch.Tensor,
    known_history: torch.Tensor,
    liked_items: torch.Tensor,
    user_rows: np.ndarray,
    known_positive_packed: np.ndarray | None,
    prepared: SequenceData,
    config: Config,
    item_correction: torch.Tensor,
    generator: torch.Generator,
    device: torch.device,
) -> tuple[torch.Tensor, torch.Tensor]:
    if config.negative_filter_scope == "full-training-history":
        if known_positive_packed is None:
            raise RuntimeError("full-history negative filter was not built")
        return draw_full_history_filtered_negatives(
            positive_items,
            user_rows,
            liked_items,
            known_positive_packed,
            len(prepared.item_ids),
            config,
            item_correction,
            generator,
            device,
        )
    return base.draw_filtered_mixed_negatives(
        positive_items,
        known_history,
        liked_items,
        len(prepared.item_ids),
        config.uniform_negatives,
        config.inbatch_negatives,
        item_correction,
        generator,
        device,
    )
31

read_file train_current_model.py

+09:28
Recorded reasoning summary 46 words

Exploring Negative Sampling

I'm currently delving into the intricacies of negative sampling during training. My focus is on understanding the mechanics of both uniform and in-batch negative selection strategies, specifically examining how torch.randint and in-batch draws contribute to the sampling process within the current batch configuration.

Recorded reasoning summary 56 words

Refining Negative Sampling Scope

I'm realizing my previous assumption about the scope of negative sampling was incorrect. It's not just drawing from n_items; uniform negatives are sampled from the entire catalog of 30,000 items, and in-batch negatives are specifically drawn from the unique targets within the current batch. This significantly broadens the pool for negative examples.

Recorded reasoning summary 40 words

Investigating Data Filtering

I'm now scrutinizing the known_positive_packed data structure and its role in filtering. My attention is drawn to how build_known_positive_filter constructs this packed representation, and the implications for identifying and excluding already-seen items from the negative sampling pool.

Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "end_line": 370,
  "file_path": "/app/solution/train_current_model.py",
  "start_line": 240
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 240-370 of 2165 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 371.

--- FILE CONTENT (truncated) ---
        (completion_sum - before_completion)
        / np.maximum(counts, 1)
        / 100.0
    ).astype(np.float16)
    return result


def build_sequence_parts(
    listens: base.ListenEvents,
    explicit: base.ExplicitEvents,
    n_items: int,
    liked_states: list[np.ndarray],
    disliked_states: list[np.ndarray],
    state_counts: list[tuple[int, int]],
) -> tuple[np.ndarray, np.ndarray, np.ndarray, np.ndarray, np.ndarray] | None:
    qualifying = listens.completion_pct >= base.LISTEN_POSITIVE_THRESHOLD
    timestamps = listens.timestamps[qualifying].astype(np.int64, copy=False)
    items = listens.items[qualifying].astype(np.uint16, copy=False)
    organic = listens.organic[qualifying].astype(np.float32, copy=False)
    completion = listens.completion_pct[qualifying].astype(np.float32, copy=False)
    if not len(items):
        return None

    event_features = np.zeros((len(items), 3), dtype=np.float16)
    event_features[:, 0] = organic.astype(np.float16)
    event_features[:, 1] = (
        np.minimum(completion, 100.0) / 100.0
    ).astype(np.float16)
    if len(items) > 1:
        gaps = np.maximum(0, timestamps[1:] - timestamps[:-1])
        event_features[1:, 2] = np.exp(
            -gaps.astype(np.float64) / (60.0 * base.DAY)
        ).astype(np.float16)

    activity = causal_activity_features(
        timestamps, items, organic, completion
    )
    states = np.zeros(len(items), dtype=np.uint32)
    active_likes: dict[int, int] = {}
    active_dislikes: dict[int, int] = {}
    explicit_position = 0
    current_state = 0
    for row, timestamp in enumerate(timestamps):
        changed = False
        while (
            explicit_position < len(explicit.timestamps)
            and int(explicit.timestamps[explicit_position]) < int(timestamp)
        ):
            item = int(explicit.items[explicit_position])
            event_timestamp = int(explicit.timestamps[explicit_position])
            destination = (
                active_likes
                if int(explicit.channel[explicit_position]) == 0
                else active_dislikes
            )
            if int(explicit.active[explicit_position]) == 1:
                destination[item] = event_timestamp
            else:
                destination.pop(item, None)
            explicit_position += 1
            changed = True
        if changed:
            current_state = append_state_snapshot(
                active_likes,
                active_dislikes,
                n_items,
                liked_states,
                disliked_states,
                state_counts,
            )
        states[row] = np.uint32(current_state)
    return timestamps, items.copy(), event_features, activity, states


def final_user_features(
    timestamps: np.ndarray,
    items: np.ndarray,
    event_features: np.ndarray,
    history_end: int,
    like_count: int,
    dislike_count: int,
) -> np.ndarray:
    start = int(
        np.searchsorted(
            timestamps,
            history_end - base.PROFILE_LOOKBACK_DAYS * base.DAY,
            side="left",
        )
    )
    result = np.zeros(6, dtype=np.float32)
    recent_items = items[start:]
    if len(recent_items):
        result[0] = np.log1p(len(recent_items)) / 8.0
        result[1] = np.log1p(len(np.unique(recent_items))) / 6.0
        result[2] = float(np.mean(event_features[start:, 0]))
        result[3] = float(np.mean(event_features[start:, 1]))
    result[4] = np.log1p(like_count) / 6.0
    result[5] = np.log1p(dislike_count) / 4.0
    return result


def prepare_data(
    public: Path, stage: str, config: Config
) -> tuple[SequenceData, CandidateSet]:
    data = public / "data"
    catalog = pd.read_parquet(data / "candidate_catalog.parquet").sort_values(
        "popularity_rank"
    )
    item_ids = catalog.item_id.to_numpy(dtype=np.int64, copy=True)
    item_index = pd.Index(item_ids)
    n_items = len(item_ids)
    if n_items >= np.iinfo(np.uint16).max:
        raise RuntimeError("uint16 item storage is too small for this catalog")

    if stage == "validation":
        prefixes = ("train",)
        history_end = base.TRAIN_END
        candidate_name = "validation_eligible_candidates.npz"
        state_name = "validation_preference_state.parquet"
    else:
        prefixes = ("train", "val")
        history_end = base.VALIDATION_END
        candidate_name = "test_eligible_candidates.npz"
        state_name = "test_preference_state.parquet"
    eligibility = CandidateSet.read(data / candidate_name)
    if not np.array_equal(eligibility.item_ids, item_ids):
        raise RuntimeError("catalog and candidate artifact item order differ")

    explicit_by_user = base.load_explicit_events(data, prefixes, item_index)
    inference_likes, inference_dislikes, like_counts, dislike_counts = (
        base.load_inference_state(
32

grep_search command

+10:02
Recorded reasoning summary 49 words

Analyzing Explicit Feedback

I'm currently digging into explicit dislikes and likes, specifically examining the dislikes.parquet and undislikes.parquet datasets. It's crucial to understand how these explicitly registered preferences align with or diverge from implicit listening data, especially considering that "listens" in build_sequence_parts are defined as positive interactions (>= 50% completion).

Recorded reasoning summary 38 words

Investigating Negative Sampling

I'm scrutinizing how explicit dislikes are handled within the current negative sampling strategy. It appears disliked_items aren't directly incorporated as hard negatives in the training process, a potential area for improvement to refine our models.

Recorded reasoning summary 49 words

Exploring Negative Sampling Strategy

I'm currently reviewing the negative sampling mechanisms within train_current_model.py, specifically config.uniform_negatives and config.inbatch_negatives. I'm also investigating the draw_full_history_filtered_negatives function to understand how in-batch negatives are presently selected and if this process can be enhanced to better incorporate explicit negative feedback while adhering to CPU constraints.

Recorded reasoning summary 56 words

Refining Negative Sampling

I'm re-examining how in-batch negatives are currently sampled. It seems only a fixed number, 8, are randomly selected from unique targets for each target, which deviates from typical two-tower approaches where all items in a larger batch serve as negatives. I'm questioning this and the ratio of 8 in-batch to 24 uniform negatives.

Recorded reasoning summary 34 words

Analyzing Loss Function

I'm scrutinizing the corrected_negative_loss and its calculation of raw, which is softplus(query_vectors @ negative_vectors). I'm now focused on understanding the role of correction within this process and its source from build_item_correction.

Recorded reasoning summary 38 words

Refining In-Batch Propensities

I'm analyzing the estimate_in_batch_propensities function. My current focus is understanding how counts are accumulated from target_counts and prepared.sequence_items. I'm also examining the calculation of probabilities and how config.inbatch_correction_power influences the raw score for in-batch negatives.

Recorded reasoning summary 47 words

Adjusting Logits via Correction

I'm re-evaluating how the correction term, derived from build_item_correction, is applied within the loss calculation. The current implementation appears to multiply a softplus(logits) term by weights, which seems counter to the standard logQ correction where $\log(p_i)$ is subtracted from logits before applying softmax.

Recorded reasoning summary 54 words

Revising Correction Logic

I'm re-evaluating the calculation of raw within the estimate_in_batch_propensities function. The current approach suggests smaller corrections for popular items due to the division by probabilities. I'm questioning the loss objective being used and if Sampled Softmax or InfoNCE is applicable given latency constraints and the prompt's emphasis on a two-tower architecture.

Recorded reasoning summary 42 words

Investigating Negative Selection

I'm focusing on how negative examples are chosen for training. I'm examining the types of negatives used, their quantity, and whether explicit dislikes are properly incorporated. My goal is to improve the current sampling strategy within our CPU constraints.

Recorded reasoning summary 37 words

Refining Negative Rejection

I'm scrutinizing how rejected in-batch negatives are handled. They're currently replaced with uniform random draws, and I'm questioning if this sufficiently addresses the underlying issue, particularly if the rejection mechanism itself is too broad.

Recorded reasoning summary 34 words

Analyzing Filter Logic

I am examining the invalid_full_history_negatives function and questioning the origin and purpose of known_positive_packed. My next step is to investigate the build_known_positive_filter function to understand how this crucial filter is constructed.

Recorded reasoning summary 28 words

Examining Filter Construction

I'm now dissecting build_known_positive_filter to fully grasp known_positive_packed. Understanding its creation is key to validating the invalid_full_history_negatives logic and its impact on negative sample selection.

Recorded reasoning summary 33 words

Validating Filter Construction

I'm now analyzing the build_known_positive_filter function, specifically the known_positive_packed construct. Understanding its creation is vital to ensure the invalid_full_history_negatives logic accurately identifies and excludes relevant positives when selecting negative samples.

Recorded reasoning summary 48 words

Analyzing Prefix Discarding

I'm noticing that the code appears to be discarding a significant prefix of user sequences, specifically items from index 0 up to the calculated window_starts for training. This prefix is then incorrectly used when building the known_positive_filter, leading to potential inaccuracies in negative sample selection.

Recorded reasoning summary 41 words

Validating Prefix Usage

I'm re-examining how sequence prefixes are used for building the positive filter. It seems the chronological BCE suffix is intended, but the current implementation might be using a discarded prefix, causing potential inaccuracies in my positive sample identification.

Recorded reasoning summary 37 words

Excluding Train Encounters

I'm confirming that all items encountered during training are rigorously excluded as candidates during validation and testing. This ensures the model isn't simply recommending what it's already seen, a critical aspect of candidate generation.

Tool callgrep_searchTool call Returned

Tool call · Input

{
  "include_pattern": "train_current_model.py",
  "dir_path": "/app/solution",
  "pattern": "build_known_positive_filter"
}

Tool response

Found 2 matches for pattern "build_known_positive_filter" in path "/app/solution" (filter: "train_current_model.py"):
---
File: train_current_model.py
L563-     )
L564-     normalization = float(np.sum(counts * raw) / max(total, 1.0))
L565-     correction = np.clip(
L566-         raw / max(normalization, 1.0e-12),
L567-         config.inbatch_correction_min,
L568-         config.inbatch_correction_max,
L569-     ).astype(np.float32)
L570-     mean_on_targets = float(np.sum(counts * correction) / max(total, 1.0))
L571-     log(
L572-         f"inbatch correction: min={correction.min():.3f} "
L573-         f"mean_on_targets={mean_on_targets:.3f} max={correction.max():.3f}"
L574-     )
L575-     return torch.from_numpy(correction)
L576- 
L577- 
L578: def build_known_positive_filter(
L579-     prepared: SequenceData, training_counts: np.ndarray
L580- ) -> np.ndarray:
L581-     """Pack each user's complete public-training positive-item set."""
L582-     width = (len(prepared.item_ids) + 7) // 8
L583-     packed = np.zeros((len(prepared.user_ids), width), dtype=np.uint8)
L584-     retained = 0
L585-     for user_row, target_count in enumerate(training_counts):
L586-         if not target_count:
L587-             continue
L588-         offset = int(prepared.offsets[user_row])
L589-         # T adjacent targets consume sequence positions 0 through T.  The
L590-         # chronological BCE suffix starts at T + 1 and is intentionally absent.
L591-         items = np.unique(
L592-             prepared.sequence_items[
L593-                 offset : offset + int(target_count) + 1
L1551-     generator = torch.Generator(device="cpu").manual_seed(config.seed + 10_000)
L1552-     item_correction = build_item_correction(
L1553-         prepared,
L1554-         config,
L1555-         partition.window_starts,
L1556-         training_counts,
L1557-     )
L1558-     target_weights = build_target_weights(
L1559-         public,
L1560-         stage,
L1561-         prepared,
L1562-         partition.history_training_counts,
L1563-         config,
L1564-     )
L1565-     known_positive_packed = (
L1566:         build_known_positive_filter(prepared, partition.history_training_counts)
L1567-         if config.negative_filter_scope == "full-training-history"
L1568-         else None
L1569-     )
L1570-     history: list[dict[str, float]] = []
L1571-     best_loss = float("inf")
L1572-     best_epoch = 0
L1573-     best_state: dict[str, torch.Tensor] | None = None
L1574-     epochs_without_improvement = 0
L1575-     start_epoch = 0
L1576- 
L1577-     if resume_checkpoint is not None:
L1578-         payload = torch.load(
L1579-             resume_checkpoint, map_location=device, weights_only=False
L1580-         )
L1581-         stored_config = payload.get("config", {})
---
33

grep_search command

+10:31
Recorded reasoning summary 51 words

Analyzing history_training_counts

I'm currently dissecting the build_known_positive_filter function, specifically focusing on how partition.history_training_counts is utilized. My attention is drawn to line 1566 where this parameter is passed. I'm investigating the exact composition of history_training_counts, with initial observations pointing to its derivation from totals = lengths - 1 and validation = floor(totals.

Recorded reasoning summary 48 words

Clarifying history_training_counts

I've further refined my understanding of history_training_counts. It appears to represent the initial 90% of a user's sequence, excluding the validation targets which are appended at the end. My next step is to examine how negative_filter_scope interacts with this, particularly in conjunction with the draw_training_negatives function.

Recorded reasoning summary 39 words

Investigating target_weighting

I am now shifting my focus to Config.target_weighting, noting its assignment as "organic-strong" in train_current_model.py. I am cross-referencing this with its definition within the build_target_weights function, specifically examining the conditions that lead to the "organic-strong" weighting implementation.

Recorded reasoning summary 33 words

Examining Config.target_weighting

My focus has shifted to Config.target_weighting, specifically the "organic-strong" setting found in train_current_model.py. I'm correlating this with its implementation within build_target_weights. I've also noted that discovery-graded is already an existing option.

Recorded reasoning summary 78 words

Analyzing Negative Sampling

I'm now delving into how negative examples are selected and utilized within the training objective, aiming to identify and address limitations in the current strategy while respecting the CPU budget. My immediate focus is on the corrected_negative_loss and the interplay between positive_loss and negative_loss in score_target_microbatches. I am also investigating the composition of sampled negatives, noting the counts for uniform and in-batch negatives, and considering how explicit dislikes or impression data might inform this process.

Tool callgrep_searchTool call Returned

Tool call · Input

{
  "dir_path": "/app/solution",
  "include_pattern": "train_current_model.py",
  "pattern": "negative"
}

Tool response

Found 88 matches for pattern "negative" in path "/app/solution" (filter: "train_current_model.py"):
---
File: train_current_model.py
L14: and 24 uniform plus eight propensity-corrected unique in-batch negatives. Every
L56:     uniform_negatives: int = 24
L57:     inbatch_negatives: int = 8
L61:     negative_filter_scope: str = "full-training-history"
L165:         uniform_negatives=config.uniform_negatives,
L166:         inbatch_negatives=config.inbatch_negatives,
L477:         "event_time_feature": "exp-negative-gap-over-60-days",
L603:         f"full-history false-negative filter: users={len(prepared.user_ids):,} "
L609: def invalid_full_history_negatives(
L610:     negatives: np.ndarray,
L616:     """Return row-level invalid negatives using the complete training prefix."""
L617:     byte_columns = negatives >> 3
L618:     bit_columns = negatives & 7
L621:     invalid |= negatives == targets[:, None]
L622:     invalid |= (negatives[:, :, None] == liked_items[:, None, :]).any(axis=2)
L623:     for column in range(1, negatives.shape[1]):
L625:             negatives[:, column, None] == negatives[:, :column]
L630: def draw_full_history_filtered_negatives(
L641:     """Draw mixed negatives and reject all known public-training positives."""
L647:         (batch_size, config.uniform_negatives),
L653:     if config.inbatch_negatives:
L656:             config.inbatch_negatives, max(len(unique_targets) - 1, 0)
L672:         if corrected_count < config.inbatch_negatives:
L675:                 (batch_size, config.inbatch_negatives - corrected_count),
L681:     negatives = torch.cat([uniform, inbatch], dim=1).numpy()
L682:     correction = np.ones_like(negatives, dtype=np.float32)
L685:             :, config.uniform_negatives : config.uniform_negatives + corrected_count
L688:         invalid = invalid_full_history_negatives(
L689:             negatives,
L697:                 torch.from_numpy(negatives).to(device),
L706:         negatives[invalid] = replacements
L709:     invalid = invalid_full_history_negatives(
L710:         negatives,
L717:         raise RuntimeError("full-history negative resampling failed")
L719:         torch.from_numpy(negatives).to(device),
L724: def draw_training_negatives(
L736:     if config.negative_filter_scope == "full-training-history":
L738:             raise RuntimeError("full-history negative filter was not built")
L739:         return draw_full_history_filtered_negatives(
L750:     return base.draw_filtered_mixed_negatives(
L755:         config.uniform_negatives,
L756:         config.inbatch_negatives,
L816:     negatives: torch.Tensor,
L818:     all_items = torch.cat([positives, negatives.reshape(-1)])
L822:     negative_vectors = encoded[inverse[len(positives) :]].reshape(
L823:         len(positives), negatives.shape[1], -1
L825:     return positive_vectors, negative_vectors
L845: def corrected_negative_loss(
L851:     total = config.uniform_negatives + config.inbatch_negatives
L853:     if config.uniform_negatives:
L854:         result += config.uniform_negatives * raw[
L855:             :, : config.uniform_negatives
L857:     if config.inbatch_negatives:
L858:         selected = slice(config.uniform_negatives, total)
L860:         result += config.inbatch_negatives * (
L880:         raise RuntimeError("chronological target partition produced negative counts")
L1119:     negatives: torch.Tensor,
L1120:     negative_weights: torch.Tensor,
L1134:         "negative_sum": 0.0,
L1162:         positive_vectors, negative_vectors = candidate_vectors(
L1165:             negatives[begin:end],
L1168:         negative_logits = torch.einsum(
L1169:             "bd,bkd->bk", query_vectors, negative_vectors
L1172:         negative_loss = corrected_negative_loss(
L1173:             negative_logits, negative_weights[begin:end], config
L1179:             selected_weights * (positive_loss + negative_loss) / 2.0
L1190:         statistics["negative_sum"] += float(negative_logits.detach().sum().cpu())
L1192:             (positive_logits.detach()[:, None] > negative_logits.detach()).sum().cpu()
L1227:     negative_count = config.uniform_negatives + config.inbatch_negatives
L1232:     total_negative = 0.0
L1293:             negatives, negative_weights = draw_training_negatives(
L1314:                 negatives,
L1315:                 negative_weights,
L1331:             total_negative += statistics["negative_sum"]
L1353:         "negative_logit": total_negative / max(total_targets * negative_count, 1),
L1355:         / max(total_targets * negative_count, 1),
L1449:             negatives, negative_weights = draw_training_negatives(
L1469:                 negatives,
L1470:                 negative_weights,
L1567:         if config.negative_filter_scope == "full-training-history"
L1601:             "negative_filter_scope", "last-100"
L1629:             stored_filter_scope != config.negative_filter_scope
L1660:                 f"{stored_filter_scope}->{config.negative_filter_scope}, "
L1944:         "--negative-filter-scope",
L1946:         default=Config.negative_filter_scope,
L2034:         negative_filter_scope=args.negative_filter_scope,
L2136:                     "negative_sampling": (
L2139:                     "false_negative_filter": config.negative_filter_scope,
---
34

read_file train_current_model.py

+10:35
Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "file_path": "/app/solution/train_current_model.py",
  "end_line": 40,
  "start_line": 1
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 1-40 of 2165 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 41.

--- FILE CONTENT (truncated) ---
#!/usr/bin/env python3
"""Train the Yambda windowed two-tower baseline.

Every catalog listen with at least 50 percent completion is a sequence token.
Within each selected chronological window, every adjacent target contributes a
loss.  The fast default retains each user's most recent 128 training targets and
16 held-out validation targets; passing zero for either cap restores the
uncapped behavior for that side of the split.  A 100-step truncated-BPTT block
computes all of its timestep losses and carries the detached GRU hidden state
into the next block.

The model is a pure two-tower retriever: no user-ID embedding, no output
normalization, raw dot-product retrieval, sample-weighted binary cross entropy,
and 24 uniform plus eight propensity-corrected unique in-batch negatives. Every
selected adjacent target retains a nonzero weight. Only files under the supplied
public directory are read.
"""
from __future__ import annotations

import argparse
import json
import random
import sys
import time
from dataclasses import asdict, dataclass
from pathlib import Path

import numpy as np
import pandas as pd
import torch
from torch import nn
from torch.nn import functional as F

import two_tower_model as base


CACHE_VERSION = 2


@dataclass(frozen=True)
35

grep_search command

+11:37
Recorded reasoning summary 46 words

Analyzing Model Architecture

I'm currently dissecting the model's architecture. It appears to be a straightforward two-tower retriever, notably omitting user IDs, output normalization, and employing raw dot-product retrieval. My focus is on understanding the implications of the sample-weighted binary cross-entropy and the specific negative sampling strategy.

Recorded reasoning summary 41 words

Refining Negative Sampling

I'm now focusing on the limitations within the current negative-sampling approach. The code for draw_full_history_filtered_negatives is under scrutiny, with particular attention paid to how it handles known positives and the potential for improvement under the fixed CPU budget.

Recorded reasoning summary 41 words

Investigating Negative Sampling Logic

I'm diving into the draw_full_history_filtered_negatives function, specifically examining how it generates uniform and in-batch negatives. I'm analyzing the use of torch.randint and the logic for selecting in-batch negatives, especially how it handles existing targets and prioritizes them.

Recorded reasoning summary 50 words

Evaluating Negative Sampling Strategy

I'm currently examining the implementation of negative sampling, particularly the logic within draw_full_history_filtered_negatives. My focus is on the generation of both uniform and in-batch negatives, paying close attention to the use of torch.randint and the selection process for in-batch negatives, including how existing targets are handled.

Recorded reasoning summary 48 words

Revising Uniform Negative Generation

I'm scrutinizing the generation of uniform negatives here, observing that replacements are drawn from torch.randint on the CPU. My current focus is on how these replacements are applied to the negatives array and how the associated correction factor is updated for these re-sampled items.

Recorded reasoning summary 42 words

Sampling In-Batch Negatives

I'm observing that in-batch negatives are sampled by selecting 8 random items from the unique targets within the batch. This seems to be done for each target, which raises questions about the logic and potential biases in this approach.

Recorded reasoning summary 30 words

Questioning In-Batch Sampling Logic

I'm questioning the uniform random sampling of in-batch negatives from unique_targets. This contradicts standard practice where negative selection should reflect data distribution popularity, not equal probability.

Recorded reasoning summary 47 words

Challenging Negative Sampling

I'm questioning the sampling of in-batch negatives from unique_targets, as it appears to be uniformly random. This seems to contradict the subsequent application of propensity correction, which penalizes popular items as if they were sampled proportionally, creating a logical inconsistency in the overall strategy.

Recorded reasoning summary 49 words

Reconsidering In-Batch Negatives

I'm now considering if in-batch items are sampled with replacement from targets, which would naturally align with popularity. I'm also questioning why only 8 in-batch negatives are used, and if they should simply be the other items in the batch, contrasting this with standard two-tower approaches.

Recorded reasoning summary 43 words

Encoding All Items

I've realized that the process of encoding items is extremely inefficient. It appears I'm encoding all 30,000 catalog items in every single step because of the way negatives are sampled and unique items are identified, which is a significant bottleneck.

Recorded reasoning summary 58 words

Revising Item Encoding

I've identified a critical inefficiency: all 30,000 catalog items are being encoded in every training step. This occurs because of how negative sampling and unique items are identified, leading to a massive computational bottleneck where the item tower MLP runs repeatedly for nearly all items, even though only a subset is used for dot products.

Recorded reasoning summary 45 words

Optimizing Item Encoding

I'm addressing the substantial inefficiency of encoding all 30,000 catalog items in every training step. This repeated encoding, driven by negative sampling and unique item identification, significantly bottlenecks the item tower MLP. I will optimize this process to run only when necessary.

Recorded reasoning summary 43 words

Refining Loss Calculation

I'm refining the negative loss calculation. Specifically, I'm analyzing how the _negative_loss function combines contributions from uniform and in-batch negatives, paying close attention to the correction weights and their impact on the final loss value, particularly within the score_target_microbatches function.

Recorded reasoning summary 48 words

Adjusting Loss Weighting

I'm questioning the division of the combined positive and negative losses by two, as this implies an equal weighting between positives and negatives. Given that each negative sample only receives 1/32 of the gradient compared to a positive, this weighting seems incorrect and needs adjustment.

Recorded reasoning summary 71 words

Improving Pair Accuracy

My focus has shifted to the unexpectedly low pair accuracy of 75.4%. This indicates that for a given positive, it only outperforms random negatives 75% of the time. Given the catalog size, this will severely hinder retrieval performance, meaning true positives will rarely rank highly. I'm investigating why this occurs, questioning the use of point-wise BCE with negative sampling and considering alternatives like Sampled Softmax, InfoNCE, or BPR.

Recorded reasoning summary 52 words

Evaluating Loss Function Choice

I'm now considering whether the binary cross-entropy loss is indeed the correct choice, especially given the prompt's focus on negative example selection and the potential need for alternatives like InfoNCE. My current thought is to re-examine the prompt and the code for definitive guidance on the objective function.

Recorded reasoning summary 45 words

Revisiting Objective Function

I'm re-examining the prompt's core directive to focus on how the training objective selects and uses negative examples. This brings me back to evaluating the suitability of binary cross-entropy versus alternatives like InfoNCE, especially concerning the specific negative sampling strategies being employed.

Recorded reasoning summary 201 words

Revising Loss Components

I'm now re-evaluating how uniform and in-batch negatives contribute to the loss, paying close attention to the impact of the correction weights on the overall _negative_loss calculation, particularly as handled within score_target_microbatches.

Adjusting Loss Weighting Scheme

I am questioning the division of combined positive and negative losses by two, as this implies an equal weighting. Given that each negative sample receives only 1/32 of the gradient compared to a positive, this weighting appears incorrect and requires adjustment.

Diagnosing Low Pair Accuracy

The pair accuracy is unexpectedly low at 75.4%. This implies that for a given positive, it only outperforms random negatives 75% of the time, which will severely hinder retrieval. I am investigating why this occurs, considering alternatives to point-wise BCE with negative sampling.

Evaluating Objective Function Suitability

I am reconsidering the choice of binary cross-entropy loss, especially in light of the prompt's emphasis on negative example selection and the potential benefits of alternatives like InfoNCE for this specific task.

Re-examining Training Objective

My focus is back on the prompt's core requirement: how the training objective selects and utilizes negative examples. This leads me to re-evaluate binary cross-entropy against options like InfoNCE, considering the current negative sampling methods.

Recorded reasoning summary 42 words

Analyzing Unique Target Identification

I'm examining the unique_targets variable, noticing it's derived from targets, which itself originates from positive_items. The length of positive_items appears to be batch_size * timesteps, creating a potentially large pool for unique_targets from which priorities are then drawn.

Recorded reasoning summary 43 words

Optimizing In-Batch Negative Selection

I'm struck by the immense memory and computational cost of generating in-batch negatives. The current priorities matrix, potentially millions of floats, is processed with torch.topk at every step. This inefficient process needs immediate re-evaluation to reduce the resource burden.

Recorded reasoning summary 44 words

Correcting In-Batch Negative Handling

I've identified an issue where invalid in-batch negatives are replaced by uniform draws with a correction factor of 1.0. This seems to override the intended propensity correction logic, potentially skewing the loss calculation and needs adjustment to ensure accurate weighting.

Recorded reasoning summary 44 words

Revising Weighted Loss Calculation

I'm analyzing the loss computation, specifically the weighted average for uniform negatives and the independent calculation for in-batch ones. It appears the final negative loss combines these with a 75/25 split, which warrants further scrutiny in light of gradient contributions.

Recorded reasoning summary 63 words

Adjusting Loss Gradient Contributions

I'm observing that the loss is calculated as the average of positive and negative losses. This implies gradients for the positive item are half the magnitude of standard BCE, and gradients for each negative item are half the magnitude of standard BCE, divided by the number of negatives. This requires adjustment to match the intended weighting and gradient contributions.

Recorded reasoning summary 40 words

Correcting Loss Gradient Magnitudes

I'm realizing the gradient contribution to individual negatives is minuscule due to averaging, diminishing their impact. This contrasts with standard methods like SGNS where the sum, not average, dictates the loss, ensuring each negative contributes meaningfully.

Recorded reasoning summary 40 words

Fixing Loss Averaging

I'm correcting an erroneous averaging operation in corrected_negative_loss. The intention was to sum negative losses for strong gradient signals, but it was instead averaging, significantly weakening each negative's impact. This fix aligns with typical contrastive learning objectives.

Recorded reasoning summary 39 words

Revising Loss Normalization

I'm identifying that the calculation currently divides the sum of losses by the total, effectively returning a mean. This, combined with subsequent division by two, incorrectly implies equal weighting between positives and negatives, which needs correction.

Recorded reasoning summary 51 words

Refining Training Objective Logic

I'm re-examining the training objective, specifically the interplay between the binary cross-entropy loss and the chosen negative sampling strategy. My current focus is on whether InfoNCE or sampled softmax would be more appropriate given the prompt's emphasis on negative example utilization and the observed low pair accuracy.

Recorded reasoning summary 51 words

Revising Training Objective Logic

I'm re-examining the training objective, specifically the interplay between the binary cross-entropy loss and the chosen negative sampling strategy. My current focus is on whether InfoNCE or sampled softmax would be more appropriate given the prompt's emphasis on negative example utilization and the observed low pair accuracy.

Recorded reasoning summary 49 words

Clarifying Objective Function

I am re-evaluating the core directive to focus on how the training objective selects and uses negative examples. This brings me back to considering InfoNCE or sampled softmax over binary cross-entropy, especially given the observed low pair accuracy and the prompt's emphasis on effective negative utilization.

Recorded reasoning summary 38 words

Challenging Uniform In-Batch Sampling

I'm reviewing the sampling of in-batch negatives from unique_targets. The current uniform random selection appears problematic, especially when contrasted with propensity correction later applied. This approach seems inconsistent with how popularity should influence sampling.

Recorded reasoning summary 43 words

Analyzing Negative Sampling Strategies

I'm currently questioning the uniform random sampling of in-batch negatives from unique_targets. This approach seems inconsistent, especially when paired with subsequent propensity correction, and I am investigating how item popularity should ideally influence negative selection in this two-tower setup.

Tool callgrep_searchTool call Returned

Tool call · Input

{
  "include_pattern": "train_current_model.py",
  "dir_path": "/app/solution",
  "pattern": "dislike"
}

Tool response

Found 33 matches for pattern "dislike" in path "/app/solution" (filter: "train_current_model.py"):
---
File: train_current_model.py
L110:     disliked_states: np.ndarray
L114:     inference_disliked_items: np.ndarray
L176:     active_dislikes: dict[int, int],
L179:     disliked_states: list[np.ndarray],
L183:     disliked_states.append(
L184:         base.pack_active_items(active_dislikes, base.DISLIKE_ITEMS, n_items)
L186:     state_counts.append((len(active_likes), len(active_dislikes)))
L252:     disliked_states: list[np.ndarray],
L279:     active_dislikes: dict[int, int] = {}
L293:                 else active_dislikes
L304:                 active_dislikes,
L307:                 disliked_states,
L320:     dislike_count: int,
L337:     result[5] = np.log1p(dislike_count) / 4.0
L369:     inference_likes, inference_dislikes, like_counts, dislike_counts = (
L383:     disliked_states = [
L384:         np.full(base.DISLIKE_ITEMS, n_items, dtype=np.uint16)
L405:             disliked_states,
L427:                 int(dislike_counts[inference_row]),
L440:             np.log1p(dislike_counts[missing]) / 4.0
L455:         disliked_states=np.stack(disliked_states),
L459:         inference_disliked_items=inference_dislikes,
L784:     disliked_items = torch.from_numpy(
L785:         prepared.disliked_states[unique_states].astype(np.int64)
L788:     disliked_vectors = model._mean_context_channel(disliked_items)
L793:         disliked_vectors[inverse_rows],
L802:     disliked_vectors: torch.Tensor,
L807:             [sequence_vectors, liked_vectors, disliked_vectors, user_features],
L1147:         liked_vectors, disliked_vectors, _ = pool_explicit_states(
L1159:             disliked_vectors,
L1844:         disliked_items = torch.from_numpy(
L1845:             prepared.inference_disliked_items[output_rows].astype(np.int64)
L1851:             model._mean_context_channel(disliked_items),
---
36

Inspect candidate catalog

+11:56
Recorded reasoning summary 42 words

Analyzing Dislike Usage

My current focus is on understanding how dislikes are integrated. It appears they serve solely as an input feature for the user tower, never as explicit negative training examples. I'm exploring the implications and potential nuances of this approach.

Recorded reasoning summary 53 words

Clarifying Candidate Exclusion

I've realized that my previous assumption about dislikes was slightly off. It turns out that any track a user has encountered, including through a dislike, is explicitly excluded from their candidate set during evaluation. This means the model will never be tested on content the user has already interacted with.

Recorded reasoning summary 51 words

Investigating Negative Sampling

I'm now digging into the specifics of how negative examples are sampled during training. It seems we're using two methods: uniform sampling from a large pool and in-batch negatives. I'm starting to question if this approach is truly optimal given the constraints and the prompt's emphasis on limitations.

Recorded reasoning summary 40 words

Analyzing Training Time

I'm investigating why training takes so long, specifically around 211 seconds per epoch. It seems the time is consumed by GRU forward/backward passes, negative sampling with resampling iterations, and item encoding. I need to scrutinize draw_full_history_filtered_negatives closely.

Recorded reasoning summary 38 words

Refining Negative Sampling

I'm examining the invalid_full_history_negatives function. It appears that rejected in-batch items are re-sampled uniformly. I'm also looking at how negative samples are generated, specifically the role of draw_full_history_filtered_negatives, to ensure optimal training given our limitations.

Tool callrun_shell_commandInspect candidate catalog Returned

Tool call · Input

{
  "command": "python -c \"\nimport pandas as pd\ncatalog = pd.read_parquet('/task/data/candidate_catalog.parquet')\nprint('Catalog columns:', catalog.columns.tolist())\nprint(catalog.head())\nprint('Shape:', catalog.shape)\nprint('Pos listens summary:\\n', catalog['positive_listens'].describe())\nprint('Organic pos listens summary:\\n', catalog['organic_positive_listens'].describe())\n\"",
  "description": "Inspect candidate catalog"
}

Tool response

<untrusted_context>
Output: Catalog columns: ['item_id', 'positive_listens', 'organic_positive_listens', 'popularity_rank']
   item_id  positive_listens  organic_positive_listens  popularity_rank
0  5862961             26615                     20620                1
1  6901374             25536                     17347                2
2  5635052             24691                     17194                3
3  3542184             24075                     17699                4
4  9378983             24036                     18195                5
Shape: (30000, 4)
Pos listens summary:
 count    30000.000000
mean       668.544300
std       1053.389553
min        163.000000
25%        228.000000
50%        354.000000
75%        669.250000
max      26615.000000
Name: positive_listens, dtype: float64
Organic pos listens summary:
 count    30000.000000
mean       313.926433
std        636.039902
min          0.000000
25%         93.000000
50%        162.000000
75%        309.000000
max      20620.000000
Name: organic_positive_listens, dtype: float64
Process Group PGID: 1742
</untrusted_context>
37

Analyze baseline ranking predictions

+12:02
Recorded reasoning summary 37 words

Analyzing Data Distribution

The extreme skew in listen counts, with a median of 354 and a maximum of 26,615, is striking. I'm now shifting to examine the baseline model's output to understand its performance against this reality.

Tool callrun_shell_commandAnalyze baseline ranking predictions Returned

Tool call · Input

{
  "command": "python -c \"\nimport pandas as pd\nimport numpy as np\n\nranking = pd.read_parquet('/app/solution/production_validation.parquet')\nprint('Ranking shape:', ranking.shape)\nprint('Number of unique items recommended:', ranking.item_id.nunique())\ncatalog = pd.read_parquet('/task/data/candidate_catalog.parquet')\nitem_pop = dict(zip(catalog.item_id, catalog.popularity_rank))\nranking['pop_rank'] = ranking.item_id.map(item_pop)\nprint('Recommended items popularity rank summary:\\n', ranking['pop_rank'].describe())\ntop_rec = ranking.item_id.value_counts().head(20)\nprint('Most frequently recommended items:')\nfor item, count in top_rec.items():\n    print(f'Item {item}: count={count} ({count/ranking.uid.nunique()*100:.1f}%), pop_rank={item_pop.get(item)}')\n\"",
  "description": "Analyze baseline ranking predictions"
}

Tool response

<untrusted_context>
Output: Ranking shape: (845600, 3)
Number of unique items recommended: 2575
Recommended items popularity rank summary:
 count    845600.000000
mean       2991.802935
std        5853.839534
min           1.000000
25%         102.000000
50%         413.000000
75%        2627.000000
max       29992.000000
Name: pop_rank, dtype: float64
Most frequently recommended items:
Item 6896222: count=5089 (60.2%), pop_rank=818
Item 7565403: count=4970 (58.8%), pop_rank=2062
Item 2055777: count=4647 (55.0%), pop_rank=1170
Item 8722394: count=4627 (54.7%), pop_rank=634
Item 5010168: count=4572 (54.1%), pop_rank=2947
Item 5134208: count=4397 (52.0%), pop_rank=306
Item 3968387: count=4160 (49.2%), pop_rank=318
Item 8823268: count=4157 (49.2%), pop_rank=76
Item 6414220: count=4155 (49.1%), pop_rank=3207
Item 8350060: count=4132 (48.9%), pop_rank=1529
Item 7227266: count=4091 (48.4%), pop_rank=919
Item 8729910: count=4036 (47.7%), pop_rank=564
Item 3375935: count=4003 (47.3%), pop_rank=282
Item 6625048: count=3992 (47.2%), pop_rank=128
Item 6006390: count=3988 (47.2%), pop_rank=75
Item 6813373: count=3960 (46.8%), pop_rank=126
Item 2408923: count=3865 (45.7%), pop_rank=111
Item 2705460: count=3815 (45.1%), pop_rank=3016
Item 1034521: count=3747 (44.3%), pop_rank=189
Item 781438: count=3710 (43.9%), pop_rank=86
Process Group PGID: 1759
</untrusted_context>
38

Analyze validation ground truth items and popularity

+12:08
Recorded reasoning summary 49 words

Discovering Recommendation Patterns

I'm analyzing the recommendation data. It appears a very small fraction of our catalog, just over 8%, is ever recommended. Notably, a significant portion of users are receiving recommendations for the same few, moderately popular items, with some items reaching over 60% of the user base.

Tool callrun_shell_commandAnalyze validation ground truth items and popularity Returned

Tool call · Input

{
  "description": "Analyze validation ground truth items and popularity",
  "command": "python -c \"\nimport pandas as pd\nfrom evaluate_public import validation_truth, CandidateSet\n\neligibility = CandidateSet('/task/data/validation_eligible_candidates.npz')\ntargets_frame = pd.read_parquet('/task/data/target_users.parquet')\ntargets = set(targets_frame.uid.astype(int))\ngraded = validation_truth(eligibility, targets)\n\ncatalog = pd.read_parquet('/task/data/candidate_catalog.parquet')\nitem_pop = dict(zip(catalog.item_id, catalog.popularity_rank))\n\nall_relevant_items = []\ngrades = []\nfor uid, items in graded.items():\n    for item, grade in items.items():\n        all_relevant_items.append(item)\n        grades.append(grade)\n\nrel_df = pd.DataFrame({'item_id': all_relevant_items, 'grade': grades})\nrel_df['pop_rank'] = rel_df.item_id.map(item_pop)\nprint(f'Scored users: {len(graded)}')\nprint(f'Total relevant user-item pairs: {len(rel_df)}')\nprint(f'Unique relevant items: {rel_df.item_id.nunique()}')\nprint('Grade distribution:\\n', rel_df.grade.value_counts())\nprint('Popularity rank summary of relevant items:\\n', rel_df.pop_rank.describe())\n\""
}

Tool response

<untrusted_context>
Output: Traceback (most recent call last):
  File "<string>", line 3, in <module>
ModuleNotFoundError: No module named 'evaluate_public'
Exit Code: 1
Process Group PGID: 1777
</untrusted_context>
39

Analyze validation ground truth items and popularity

+12:14
Tool callrun_shell_commandAnalyze validation ground truth items and popularity Returned

Tool call · Input

{
  "command": "python -c \"\nimport sys\nsys.path.append('/task')\nimport pandas as pd\nfrom evaluate_public import validation_truth, CandidateSet\n\neligibility = CandidateSet('/task/data/validation_eligible_candidates.npz')\ntargets_frame = pd.read_parquet('/task/data/target_users.parquet')\ntargets = set(targets_frame.uid.astype(int))\ngraded = validation_truth(eligibility, targets)\n\ncatalog = pd.read_parquet('/task/data/candidate_catalog.parquet')\nitem_pop = dict(zip(catalog.item_id, catalog.popularity_rank))\n\nall_relevant_items = []\ngrades = []\nfor uid, items in graded.items():\n    for item, grade in items.items():\n        all_relevant_items.append(item)\n        grades.append(grade)\n\nrel_df = pd.DataFrame({'item_id': all_relevant_items, 'grade': grades})\nrel_df['pop_rank'] = rel_df.item_id.map(item_pop)\nprint(f'Scored users: {len(graded)}')\nprint(f'Total relevant user-item pairs: {len(rel_df)}')\nprint(f'Unique relevant items: {rel_df.item_id.nunique()}')\nprint('Grade distribution:\\n', rel_df.grade.value_counts())\nprint('Popularity rank summary of relevant items:\\n', rel_df.pop_rank.describe())\n\"",
  "description": "Analyze validation ground truth items and popularity"
}

Tool response

<untrusted_context>
Output: Scored users: 4263
Total relevant user-item pairs: 37769
Unique relevant items: 14124
Grade distribution:
 grade
1    33352
3     4417
Name: count, dtype: int64
Popularity rank summary of relevant items:
 count    37769.000000
mean      8463.087744
std       8117.953262
min          1.000000
25%       1733.000000
50%       5622.000000
75%      13374.000000
max      30000.000000
Name: pop_rank, dtype: float64
Process Group PGID: 1788
</untrusted_context>
40

Test training speed with prepared cache

+12:33
Recorded reasoning summary 41 words

Analyzing Ground Truth Data

I've been dissecting the validation ground truth, noting 4,263 scored users and 37,769 relevant user-item pairs. The sheer volume of 14,124 unique relevant items is striking, with a median popularity rank of 5,6 indicating their relative commonality.

Recorded reasoning summary 48 words

Investigating Popularity Bias

I'm digging into the baseline's predictions. It's heavily skewed towards the most popular items, predicting only a fraction of unique items compared to what users actually engage with. I'm now analyzing why this two-tower model exhibits such extreme popularity bias during training and negative sampling.

Recorded reasoning summary 39 words

Understanding Negative Sampling

My recent focus has been on in-batch negative sampling. I've realized that with uniform sampling, popular items are rarely chosen as negatives, leading to skewed positive embeddings and a strong bias towards high-popularity items in predictions.

Recorded reasoning summary 43 words

Revising Negative Sampling Strategy

I've realized my previous assumptions about in-batch negative sampling were inverted. Popular items are sampled as negatives far more frequently than I initially thought, which actually helps to counteract popularity bias. This insight is crucial for refining my approach.

Recorded reasoning summary 47 words

Adjusting In-Batch Sampling

I've discovered my previous understanding of unique_targets was flawed; it actually evens out popular and rare items, effectively destroying the true negative distribution. Furthermore, the item_correction mechanism, when applied to popular items with small weights, significantly reduces their influence on the weighted average loss.

Recorded reasoning summary 41 words

Refining Loss Calculations

I've discovered that popular items were paradoxically penalized less in the negative loss. The subsequent averaging mechanism compounded this. My current focus is on understanding how different loss functions, like pointwise BCE versus InfoNCE, directly impact ranking optimization.

Recorded reasoning summary 49 words

Correcting Item Bias

I'm now exploring how to apply logQ correction to InfoNCE. The aim is to adjust the logits by subtracting the log probability of each item, effectively debiasing the training signal and ensuring raw dot products are used for final ranking, as per Yi et al. 2019.

Tool callrun_shell_commandTest training speed with prepared cache Returned

Tool call · Input

{
  "description": "Test training speed with prepared cache",
  "command": "python /app/solution/train_current_model.py \\\n  --stage validation \\\n  --public-dir /task \\\n  --prepared-cache /app/solution/prepared_val.npz \\\n  --output /app/solution/test_cache.parquet"
}

Tool response

<untrusted_context>
Output: loaded full-sequence cache: tokens=20,056,329 targets=20,047,194
chronological BCE window: train=1,052,953 validation=130,103 selected=1,183,056 discarded_old_targets=18,864,138 all=20,047,194
inbatch correction: min=0.250 mean_on_targets=1.001 max=4.000
target weighting=organic-strong min=0.250 mean=0.575 max=1.000
full-history false-negative filter: users=9,135 unique_user_items=5,524,275 bytes=34,256,250
epoch=1/1 batches=250 targets=987,417 batch_bce=0.547529 running_bce=0.541614 elapsed=196.5s
epoch=1/1 train_loss=0.53984 validation_loss=0.49664 pair_accuracy=0.755 train_targets=1,052,953 validation_targets=130,103 train_seconds=209.5 validation_seconds=14.8
restored best validation-BCE checkpoint: epoch=1 loss=0.496636
ranked users=1,024/8,456
ranked users=2,048/8,456
ranked users=3,072/8,456
ranked users=4,096/8,456
ranked users=5,120/8,456
ranked users=6,144/8,456
ranked users=7,168/8,456
ranked users=8,192/8,456
ranked users=8,456/8,456
{
  "baseline": "yambda-windowed-sequence-two-tower-base",
  "stage": "validation",
  "output": "/app/solution/test_cache.parquet",
  "rows": 845600,
  "users": 8456,
  "runtime_seconds": 306.476,
  "public_inputs_only": true,
  "architecture": {
    "family": "pure-windowed-sequence-two-tower",
    "sequence_training": "every-adjacent-target-within-recent-chronological-window",
    "sequence_encoder": "one-layer-GRU-dense-timestep-loss",
    "bptt_hidden_state": "carried-and-detached",
    "model_selection": "chronological-validation-BCE-early-stopping",
    "loss_execution": "gradient-accumulated-microbatches",
    "user_id_embedding": false,
    "user_mlp": "582-512-256-192",
    "item_mlp": "196-512-256-192",
    "normalization": "none",
    "score": "raw-dot-product",
    "objective": "sample-weighted-BCE-at-every-timestep",
    "negative_sampling": "24-uniform-plus-8-propensity-corrected-inbatch",
    "false_negative_filter": "full-training-history",
    "target_weighting": "organic-strong"
  },
  "config": {
    "bptt_steps": 100,
    "user_batch_size": 64,
    "embedding_dim": 192,
    "hidden_dim": 192,
    "user_hidden_1": 512,
    "user_hidden_2": 256,
    "item_hidden_1": 512,
    "item_hidden_2": 256,
    "dropout": 0.05,
    "epochs": 1,
    "learning_rate": 0.001,
    "weight_decay": 1e-05,
    "gradient_clip": 2.0,
    "loss_microbatch_size": 65536,
    "uniform_negatives": 24,
    "inbatch_negatives": 8,
    "inbatch_correction_power": 0.5,
    "inbatch_correction_min": 0.25,
    "inbatch_correction_max": 4.0,
    "negative_filter_scope": "full-training-history",
    "target_weighting": "organic-strong",
    "ordinary_target_weight": 0.25,
    "organic_strong_target_weight": 1.0,
    "organic_like_target_weight": 3.0,
    "discovery_horizon_days": 7,
    "validation_fraction": 0.1,
    "max_train_targets_per_user": 128,
    "max_validation_targets_per_user": 16,
    "early_stopping_patience": 1,
    "early_stopping_min_delta": 0.0001,
    "seed": 29
  },
  "sequence_tokens": 20056329,
  "all_next_item_targets": 20047194,
  "selected_training_targets": 1052953,
  "selected_validation_targets": 130103,
  "discarded_old_targets": 18864138,
  "training_history": [
    {
      "epoch": 1.0,
      "loss": 0.5398380473223814,
      "positive_logit": 0.7427799578701499,
      "negative_logit": -0.6222247038719716,
      "pair_accuracy": 0.7547733612041563,
      "targets": 1052953.0,
      "target_weight_sum": 632551.0,
      "batches": 266.0,
      "seconds": 209.497521838,
      "validation_loss": 0.4966362164658338,
      "validation_targets": 130103.0,
      "validation_target_weight_sum": 78769.25,
      "validation_seconds": 14.751028146999943
    }
  ],
  "embedding_diagnostics": {
    "query_norm_mean": 1.603016972541809,
    "query_norm_std": 0.7697497010231018,
    "item_norm_mean": 1.7570279836654663,
    "item_norm_std": 0.8279485702514648
  },
  "torch_version": "2.8.0+cpu",
  "device": "cpu"
}
Process Group PGID: 1808
</untrusted_context>
41

Remove temporary test file

+17:48
Tool callrun_shell_commandRemove temporary test file Returned

Tool call · Input

{
  "description": "Remove temporary test file",
  "command": "rm -f /app/solution/test_cache.parquet"
}

Tool response

<untrusted_context>
Output: (empty)
Process Group PGID: 1833
</untrusted_context>
42

Build submission data cache

+17:51
Recorded reasoning summary 39 words

Saving Baseline Submission

Before proceeding with testing any enhancements, I'm ensuring a valid baseline submission is securely stored. This is crucial for preserving our best result, especially as the deadline approaches, and I'm checking the --stage submission command's output.

Tool callrun_shell_commandBuild submission data cache Returned

Tool call · Input

{
  "command": "python /app/solution/train_current_model.py \\\n  --stage submission \\\n  --public-dir /task \\\n  --prepared-cache /app/solution/prepared_sub.npz \\\n  --output /app/solution/dummy.parquet \\\n  --prepare-only",
  "description": "Build submission data cache"
}

Tool response

<untrusted_context>
Output: loaded explicit events: rows=746,504 users=8,307
prepared users=1,000 tokens=2,167,338 states=37,073 elapsed=5.2s
prepared users=2,000 tokens=4,450,246 states=73,784 elapsed=10.5s
prepared users=3,000 tokens=6,703,970 states=113,190 elapsed=15.9s
prepared users=4,000 tokens=9,087,187 states=153,283 elapsed=21.6s
prepared users=5,000 tokens=11,354,844 states=188,776 elapsed=26.7s
prepared users=6,000 tokens=13,485,786 states=224,384 elapsed=31.7s
prepared users=7,000 tokens=15,826,114 states=265,318 elapsed=37.5s
prepared users=8,000 tokens=18,028,622 states=306,474 elapsed=43.1s
prepared users=9,000 tokens=20,195,749 states=342,272 elapsed=48.1s
target users without qualifying catalog sequence=6
prepared stage=submission sequence_users=9,153 tokens=20,712,971 next_item_targets=20,703,818 states=350,322
saved public-derived full-sequence cache: /app/solution/prepared_sub.npz
{
  "stage": "submission",
  "sequence_users": 9153,
  "sequence_tokens": 20712971,
  "next_item_targets": 20703818,
  "selected_training_targets": 1067606,
  "selected_validation_targets": 131997,
  "discarded_old_targets": 19504215,
  "target_users": 8456,
  "runtime_seconds": 53.311,
  "config": {
    "bptt_steps": 100,
    "user_batch_size": 64,
    "embedding_dim": 192,
    "hidden_dim": 192,
    "user_hidden_1": 512,
    "user_hidden_2": 256,
    "item_hidden_1": 512,
    "item_hidden_2": 256,
    "dropout": 0.05,
    "epochs": 1,
    "learning_rate": 0.001,
    "weight_decay": 1e-05,
    "gradient_clip": 2.0,
    "loss_microbatch_size": 65536,
    "uniform_negatives": 24,
    "inbatch_negatives": 8,
    "inbatch_correction_power": 0.5,
    "inbatch_correction_min": 0.25,
    "inbatch_correction_max": 4.0,
    "negative_filter_scope": "full-training-history",
    "target_weighting": "organic-strong",
    "ordinary_target_weight": 0.25,
    "organic_strong_target_weight": 1.0,
    "organic_like_target_weight": 3.0,
    "discovery_horizon_days": 7,
    "validation_fraction": 0.1,
    "max_train_targets_per_user": 128,
    "max_validation_targets_per_user": 16,
    "early_stopping_patience": 1,
    "early_stopping_min_delta": 0.0001,
    "seed": 29
  }
}
Process Group PGID: 1836
</untrusted_context>
43

Create initial valid fallback submission.parquet and validate constraints

+18:54
Recorded reasoning summary 29 words

Finalizing Baseline Submission

My focus has shifted to generating a valid baseline submission using the now-prepared cache files. I'm setting up /app/solution/submission to ensure a complete, albeit basic, output.

Tool callrun_shell_commandCreate initial valid fallback submission.parquet and validate constraints Returned

Tool call · Input

{
  "command": "python -c \"\nimport numpy as np\nimport pandas as pd\nfrom ranking_evaluation import CandidateSet, validate_ranking, ranked_items\n\neligibility = CandidateSet('/task/data/test_eligible_candidates.npz')\ntargets_frame = pd.read_parquet('/task/data/target_users.parquet')\ntargets = set(targets_frame.uid.astype(int))\n\nrows = []\nfor idx, uid in enumerate(eligibility.uids):\n    mask = np.unpackbits(eligibility.packed[idx], count=len(eligibility.item_ids), bitorder='little').astype(bool)\n    eligible_items = eligibility.item_ids[mask]\n    # pick top 100 eligible items\n    top100 = eligible_items[:100]\n    for r, item in enumerate(top100, 1):\n        rows.append((int(uid), int(item), r))\n\ndf = pd.DataFrame(rows, columns=['uid', 'item_id', 'rank'])\ndf.to_parquet('/app/solution/submission.parquet', index=False)\nprint('Generated fallback submission with shape:', df.shape)\n\n# Validate it\nvalidated = validate_ranking(df, targets)\nprint('Validated successfully! Rows:', len(validated))\n\"",
  "description": "Create initial valid fallback submission.parquet and validate constraints"
}

Tool response

<untrusted_context>
Output: Traceback (most recent call last):
  File "<string>", line 4, in <module>
ModuleNotFoundError: No module named 'ranking_evaluation'
Exit Code: 1
Process Group PGID: 1860
</untrusted_context>
44

Create initial valid fallback submission.parquet and validate constraints

+19:00
Tool callrun_shell_commandCreate initial valid fallback submission.parquet and validate constraints Returned

Tool call · Input

{
  "command": "PYTHONPATH=/task python -c \"\nimport numpy as np\nimport pandas as pd\nfrom ranking_evaluation import CandidateSet, validate_ranking, ranked_items\n\neligibility = CandidateSet('/task/data/test_eligible_candidates.npz')\ntargets_frame = pd.read_parquet('/task/data/target_users.parquet')\ntargets = set(targets_frame.uid.astype(int))\n\nrows = []\nfor idx, uid in enumerate(eligibility.uids):\n    mask = np.unpackbits(eligibility.packed[idx], count=len(eligibility.item_ids), bitorder='little').astype(bool)\n    eligible_items = eligibility.item_ids[mask]\n    top100 = eligible_items[:100]\n    for r, item in enumerate(top100, 1):\n        rows.append((int(uid), int(item), r))\n\ndf = pd.DataFrame(rows, columns=['uid', 'item_id', 'rank'])\ndf.to_parquet('/app/solution/submission.parquet', index=False)\nprint('Generated fallback submission with shape:', df.shape)\n\nvalidated = validate_ranking(df, targets)\nprint('Validated successfully! Rows:', len(validated))\n\"",
  "description": "Create initial valid fallback submission.parquet and validate constraints"
}

Tool response

<untrusted_context>
Output: Generated fallback submission with shape: (845600, 3)
Validated successfully! Rows: 845600
Process Group PGID: 1871
</untrusted_context>
45

update_topic command

+19:08
Recorded reasoning summary 50 words

Establishing Baseline Submission

My current focus is on ensuring the integrity of the baseline submission file located at /app/solution/submission.parquet. I've confirmed it adheres to all invariant requirements, including the precise row count of 845,600, the presence of uid, item_id, and rank columns, and the inclusion of only eligible candidate items.

Tool callupdate_topicTool call Returned

Tool call · Input

{
  "strategic_intent": "Formulate diagnoses of the current negative-sampling and loss implementation, then run empirical backtests on public validation.",
  "title": "Diagnosing and Improving Negative Sampling and Training Objective",
  "summary": "We have successfully reproduced the baseline validation score (0.02128), cached both validation and submission preprocessed sequences to accelerate training by 50 seconds per run, and verified an initial fallback submission. We analyzed the baseline recommendations, discovering severe popularity bias (only 2,575 unique items recommended, median popularity rank 413) whereas true relevant discovery items have median popularity rank 5,622 across 14,124 unique items. We are now transitioning to systematically diagnosing and improving the negative-sampling strategy and loss objective."
}

Tool response

Current topic: "Diagnosing and Improving Negative Sampling and Training Objective"
Topic summary: We have successfully reproduced the baseline validation score (0.02128), cached both validation and submission preprocessed sequences to accelerate training by 50 seconds per run, and verified an initial fallback submission. We analyzed the baseline recommendations, discovering severe popularity bias (only 2,575 unique items recommended, median popularity rank 413) whereas true relevant discovery items have median popularity rank 5,622 across 14,124 unique items. We are now transitioning to systematically diagnosing and improving the negative-sampling strategy and loss objective.

Strategic Intent: Formulate diagnoses of the current negative-sampling and loss implementation, then run empirical backtests on public validation.
46

Benchmark unique_items in candidate_vectors

+19:31
Recorded reasoning summary 46 words

Analyzing Baseline Model Details

I'm currently digging into the specifics of the baseline model, including its negative sampling strategy and how the loss function is configured. My focus is on understanding how these elements contribute to the overall performance and efficiency within the given latency constraints.

Recorded reasoning summary 52 words

Refining Negative Sampling Tactics

My analysis is zeroing in on the trainer's negative sampling mechanism, specifically its mix of uniform and in-batch negatives and the correctional power applied. I'm probing how this impacts the objective's selection and usage of these examples to identify limitations and opportunities for improvement within the CPU budget.

Recorded reasoning summary 44 words

Exploring Target Weighting

I'm investigating the impact of switching the target weighting strategy to "discovery-graded." This seems pertinent given the task's grading system, and I want to see how it influences the objective's selection and utilization of negatives compared to the current "organic-strong" setting.

Recorded reasoning summary 40 words

Investigating Loss Calculation

I'm examining the corrected_negative_loss function and its interaction with score_target_microbatches. Specifically, I'm analyzing how the distribution of uniform and in-batch negatives, along with the correction tensor's weights, influences the calculation of the raw and final loss values.

Recorded reasoning summary 49 words

Tracing Loss Calculation Path

I'm currently tracing the mathematical flow within the loss calculation. My focus is on how negative_logits are computed via einsum, and the subsequent softplus application to both positive and negative logits. I'm also examining the averaging and weighting steps before summing to the final loss.

Recorded reasoning summary 75 words

Evaluating Pair Accuracy Needs

My current focus is on the implications of the observed 75% pair accuracy. It seems that achieving a top-100 ranking for the true positive at inference time necessitates a pair accuracy of 99.7%. I'm analyzing why the current loss function falls short of this, particularly how it doesn't directly enforce a sufficient margin between positive and negative scores and how the division by K in negative loss diminishes individual negative gradients.

Recorded reasoning summary 43 words

Comparing Loss Functions

I'm comparing how my current loss function dilutes the impact of a strong negative compared to InfoNCE, which directly couples positive and negative logits. InfoNCE's softmax gradient automatically hard-negative weights and its temperature parameter sharpens the distribution, influencing gradients differently.

Recorded reasoning summary 47 words

Considering Alternative Loss Functions

I'm evaluating other loss functions like BPR and Margin Ranking Loss, which directly optimize score differences. I'm also contemplating whether InfoNCE or a logQ-corrected InfoNCE might be more effective. I've noticed specific validation evaluation functions and early stopping criteria in the training script.

Recorded reasoning summary 46 words

Optimizing Epoch Speed

I'm investigating the 209-second epoch duration. It seems the bottleneck lies within run_training_epoch, specifically the draw_training_negatives function. I'm analyzing its complex steps, including generating uniform negatives, finding unique targets, and the iterative rejection sampling process for invalid histories, to identify potential performance improvements.

Tool callrun_shell_commandBenchmark unique_items in candidate_vectors Returned

Tool call · Input

{
  "description": "Benchmark unique_items in candidate_vectors",
  "command": "python -c \"\nimport time\nimport torch\nimport numpy as np\n\n# Simulate candidate_vectors with unique_items\nB = 5000\nK = 32\npositives = torch.randint(0, 30000, (B,))\nnegatives = torch.randint(0, 30000, (B, K))\n\nt0 = time.time()\nall_items = torch.cat([positives, negatives.reshape(-1)])\nunique_items, inverse = torch.unique(all_items, return_inverse=True)\nt1 = time.time()\nprint(f'Unique items: {len(unique_items)} out of {len(all_items)} in {(t1-t0)*1000:.2f}ms')\n\""
}

Tool response

<untrusted_context>
Output: Unique items: 29873 out of 165000 in 4.72ms
Process Group PGID: 1887
</untrusted_context>
47

Benchmark encode_items for 30000 items

+19:38
Recorded reasoning summary 39 words

Observing Item Distribution

I'm noticing a consistent pattern where the unique_items count hovers around 29,873 per batch. This high figure, given the catalog size and the inclusion of uniform negatives, suggests we're effectively sampling nearly the entire item pool.

Tool callrun_shell_commandBenchmark encode_items for 30000 items Returned

Tool call · Input

{
  "description": "Benchmark encode_items for 30000 items",
  "command": "python -c \"\nimport time\nimport torch\nimport sys\nsys.path.append('/app/solution')\nimport two_tower_model as base\n\ncatalog_feat = torch.randn(30000, 4)\nconfig = base.TowerConfig()\nmodel = base.SequentialTwoTower(catalog_feat.numpy(), config)\n\nitems = torch.arange(30000)\nfor _ in range(5):\n    t0 = time.time()\n    out = model.encode_items(items)\n    t1 = time.time()\n    print(f'encode_items 30000 items: {(t1-t0)*1000:.2f}ms')\n\""
}

Tool response

<untrusted_context>
Output: encode_items 30000 items: 320.97ms
encode_items 30000 items: 322.79ms
encode_items 30000 items: 316.61ms
encode_items 30000 items: 308.11ms
encode_items 30000 items: 296.00ms
Process Group PGID: 1900
</untrusted_context>
48

Check unique targets in typical batch

+19:48
Recorded reasoning summary 31 words

Measuring Encoding Efficiency

My recent analysis confirms encoding 30,000 items requires approximately 310ms, with the backward pass adding another 400ms. This translates to roughly 186 seconds per epoch, considering 266 batches.

Tool callrun_shell_commandCheck unique targets in typical batch Returned

Tool call · Input

{
  "command": "python -c \"\nimport numpy as np\n\n# In a typical batch of 5000 targets from listening data:\n# How many unique items?\n# Let's test with real data!\ndata = np.load('/app/solution/prepared_val.npz')\nseq = data['sequence_items'][:5000]\nprint('Unique targets in 5000 targets:', len(np.unique(seq)))\n\"",
  "description": "Check unique targets in typical batch"
}

Tool response

<untrusted_context>
Output: Unique targets in 5000 targets: 1896
Process Group PGID: 1914
</untrusted_context>
49

Evaluate baseline with discovery-graded target weighting

+20:06
Recorded reasoning summary 45 words

Optimizing Item Encoding

I've realized the significant performance bottleneck: encoding nearly 2,000 unique items across 5,000 targets. By optimizing this, encoding time has dropped from 320ms to approximately 20ms, a fifteen-fold improvement. I'm now re-evaluating the prompt's emphasis on request-time latency and item vector constraints.

Recorded reasoning summary 45 words

Investigating Negative Sampling

My focus has shifted to the training objective and how it selects negative examples. I'm digging into the limitations of our current negative sampling strategy, aiming to improve it within the existing CPU constraints and validate these changes via the public backtest.

Recorded reasoning summary 47 words

Refining Negative Sampling

I'm analyzing our current negative sampling, which draws uniformly from the entire catalog, leading to popular items being rarely chosen as negatives. I'm exploring strategies to incorporate hard negatives, like popular or similar items the user hasn't interacted with, to improve the training objective.

Recorded reasoning summary 42 words

Evaluating Negative Sampling Strategy

I'm examining the trade-offs between in-batch and uniform negative sampling. In-batch negatives appear crucial for capturing interaction popularity and providing harder examples. The current loss function dilutes negative penalties and lacks competitive ranking between positive and negative items.

Recorded reasoning summary 40 words

Adjusting Negative Sample Weights

I've identified an issue where popular items, when sampled as negatives, are actually downweighted in the loss function. This counterintuitively prevents the model from learning to penalize them effectively. I'm exploring how to invert this behavior.

Recorded reasoning summary 43 words

Correcting Popularity Bias

I'm now applying the Yi et al. (2019) correction. Subtracting $\log(p_i)$ from the logit of popular items reduces their influence during training, forcing the model to learn genuine relevance over mere popularity. This should resolve the over-prediction of popular items.

Recorded reasoning summary 52 words

Improving Relevance Estimation

I've implemented the Yi et al. correction to account for item popularity in my loss function. This adjustment debiases the training by subtracting item popularity probabilities, ensuring the model learns genuine user preference rather than just popular items. This should rectify the over-prediction of highly popular items during inference.

Tool callrun_shell_commandEvaluate baseline with discovery-graded target weighting Returned

Tool call · Input

{
  "description": "Evaluate baseline with discovery-graded target weighting",
  "command": "python /app/solution/train_current_model.py \\\n  --stage validation \\\n  --public-dir /task \\\n  --prepared-cache /app/solution/prepared_val.npz \\\n  --target-weighting discovery-graded \\\n  --output /app/solution/val_discovery_graded.parquet\npython /task/evaluate_public.py /app/solution/val_discovery_graded.parquet"
}

Tool response

<untrusted_context>
Output: loaded full-sequence cache: tokens=20,056,329 targets=20,047,194
chronological BCE window: train=1,052,953 validation=130,103 selected=1,183,056 discarded_old_targets=18,864,138 all=20,047,194
inbatch correction: min=0.250 mean_on_targets=1.001 max=4.000
loaded organic-like outcomes: rows=301,527 users=7,526
grade-3 first-encounter targets=46,417 horizon_days=7
target weighting=discovery-graded min=0.250 mean=0.310 max=3.000
full-history false-negative filter: users=9,135 unique_user_items=5,524,275 bytes=34,256,250
epoch=1/1 batches=250 targets=987,417 batch_bce=0.551810 running_bce=0.544138 elapsed=195.4s
epoch=1/1 train_loss=0.54212 validation_loss=0.50483 pair_accuracy=0.760 train_targets=1,052,953 validation_targets=130,103 train_seconds=208.3 validation_seconds=15.2
restored best validation-BCE checkpoint: epoch=1 loss=0.504831
ranked users=1,024/8,456
ranked users=2,048/8,456
ranked users=3,072/8,456
ranked users=4,096/8,456
ranked users=5,120/8,456
ranked users=6,144/8,456
ranked users=7,168/8,456
ranked users=8,192/8,456
ranked users=8,456/8,456
{
  "baseline": "yambda-windowed-sequence-two-tower-base",
  "stage": "validation",
  "output": "/app/solution/val_discovery_graded.parquet",
  "rows": 845600,
  "users": 8456,
  "runtime_seconds": 312.362,
  "public_inputs_only": true,
  "architecture": {
    "family": "pure-windowed-sequence-two-tower",
    "sequence_training": "every-adjacent-target-within-recent-chronological-window",
    "sequence_encoder": "one-layer-GRU-dense-timestep-loss",
    "bptt_hidden_state": "carried-and-detached",
    "model_selection": "chronological-validation-BCE-early-stopping",
    "loss_execution": "gradient-accumulated-microbatches",
    "user_id_embedding": false,
    "user_mlp": "582-512-256-192",
    "item_mlp": "196-512-256-192",
    "normalization": "none",
    "score": "raw-dot-product",
    "objective": "sample-weighted-BCE-at-every-timestep",
    "negative_sampling": "24-uniform-plus-8-propensity-corrected-inbatch",
    "false_negative_filter": "full-training-history",
    "target_weighting": "discovery-graded"
  },
  "config": {
    "bptt_steps": 100,
    "user_batch_size": 64,
    "embedding_dim": 192,
    "hidden_dim": 192,
    "user_hidden_1": 512,
    "user_hidden_2": 256,
    "item_hidden_1": 512,
    "item_hidden_2": 256,
    "dropout": 0.05,
    "epochs": 1,
    "learning_rate": 0.001,
    "weight_decay": 1e-05,
    "gradient_clip": 2.0,
    "loss_microbatch_size": 65536,
    "uniform_negatives": 24,
    "inbatch_negatives": 8,
    "inbatch_correction_power": 0.5,
    "inbatch_correction_min": 0.25,
    "inbatch_correction_max": 4.0,
    "negative_filter_scope": "full-training-history",
    "target_weighting": "discovery-graded",
    "ordinary_target_weight": 0.25,
    "organic_strong_target_weight": 1.0,
    "organic_like_target_weight": 3.0,
    "discovery_horizon_days": 7,
    "validation_fraction": 0.1,
    "max_train_targets_per_user": 128,
    "max_validation_targets_per_user": 16,
    "early_stopping_patience": 1,
    "early_stopping_min_delta": 0.0001,
    "seed": 29
  },
  "sequence_tokens": 20056329,
  "all_next_item_targets": 20047194,
  "selected_training_targets": 1052953,
  "selected_validation_targets": 130103,
  "discarded_old_targets": 18864138,
  "training_history": [
    {
      "epoch": 1.0,
      "loss": 0.5421154191580255,
      "positive_logit": 0.7774311369950272,
      "negative_logit": -0.6407561995894085,
      "pair_accuracy": 0.7602795720701684,
      "targets": 1052953.0,
      "target_weight_sum": 348780.0,
      "batches": 266.0,
      "seconds": 208.31431418599982,
      "validation_loss": 0.5048305711216913,
      "validation_targets": 130103.0,
      "validation_target_weight_sum": 42129.5,
      "validation_seconds": 15.20520111399992
    }
  ],
  "embedding_diagnostics": {
    "query_norm_mean": 1.7521852254867554,
    "query_norm_std": 0.8638167977333069,
    "item_norm_mean": 1.8543914556503296,
    "item_norm_std": 0.8459439277648926
  },
  "torch_version": "2.8.0+cpu",
  "device": "cpu"
}
{
  "model": "/app/solution/val_discovery_graded.parquet",
  "scores": {
    "quality_ndcg@10": 0.023522,
    "quality_users": 4263
  }
}
Process Group PGID: 1924
</untrusted_context>
50

Remove temporary validation parquet

+25:30
Tool callrun_shell_commandRemove temporary validation parquet Returned

Tool call · Input

{
  "command": "rm -f /app/solution/val_discovery_graded.parquet",
  "description": "Remove temporary validation parquet"
}

Tool response

<untrusted_context>
Output: (empty)
Process Group PGID: 1973
</untrusted_context>
51

Benchmark matrix multiplication 6400x192 @ 192x6400

+25:51
Recorded reasoning summary 43 words

Deepening Negative Sampling

I'm now delving into the intricacies of negative sampling and the loss function. My focus is on a detailed examination, ensuring alignment with the project's mature baseline and chronological validation requirements. This deep dive aims to refine our approach significantly.

Recorded reasoning summary 49 words

Analyzing Negative Sampling Logic

I'm currently investigating how our training objective selects and utilizes negative examples. My focus is on diagnosing limitations within the current strategy and improving it while adhering to the CPU budget. I'll validate these changes with the public backtest to ensure we meet all constraints.

Recorded reasoning summary 33 words

Refining Negative Sampling Methods

I'm currently implementing a more sophisticated negative sampling strategy. This involves drawing mixed negatives and ensuring all known public-training positives are rejected, aiming for a robust and efficient approach.

Recorded reasoning summary 49 words

Optimizing Negative Sample Generation

I'm now refining the generation of negative samples, specifically focusing on how we select and correct them. My attention is on efficiently handling unique targets and incorporating both uniform and in-batch negatives, ensuring we meet performance targets within the CPU budget while addressing invalid samples.

Recorded reasoning summary 42 words

Correcting Negative Sample Errors

I'm now addressing errors arising during negative sample generation. My current focus is on the correction mechanism for invalid samples, specifically how rejected in-batch items are handled as uniform draws. This ensures the integrity of the training data.

Recorded reasoning summary 47 words

Investigating Resampling Logic

I'm closely examining the resampling process, specifically how invalid in-batch negatives are replaced with uniform draws. My focus is on quantifying these replacements and understanding the composition of in-batch negatives, particularly how unique targets might inadvertently include items the user has already interacted with.

Recorded reasoning summary 47 words

Revising Negative Sampling Strategy

I'm reconsidering our negative sampling approach, moving away from fixed ratios of uniform and in-batch negatives. My focus is on exploring the benefits of increasing in-batch negatives, inspired by techniques like Mixed Negative Sampling, for improved efficiency and coverage of the data distribution.

Recorded reasoning summary 42 words

Analyzing In-Batch Filtering

I'm now dissecting how in-batch negative items are filtered. My focus is on the process where an item already interacted with by a specific user is masked out, preventing it from being a valid negative for that particular user.

Tool callrun_shell_commandBenchmark matrix multiplication 6400x192 @ 192x6400 Returned

Tool call · Input

{
  "description": "Benchmark matrix multiplication 6400x192 @ 192x6400",
  "command": "python -c \"\nimport torch\nimport time\n\nQ = torch.randn(6400, 192)\nV = torch.randn(6400, 192)\n\nfor _ in range(5):\n    t0 = time.time()\n    S = Q @ V.T\n    t1 = time.time()\n    print(f'6400x192 @ 192x6400: {(t1-t0)*1000:.2f}ms')\n\""
}

Tool response

<untrusted_context>
Output: 6400x192 @ 192x6400: 73.15ms
6400x192 @ 192x6400: 87.33ms
6400x192 @ 192x6400: 87.84ms
6400x192 @ 192x6400: 83.32ms
6400x192 @ 192x6400: 82.71ms
Process Group PGID: 1976
</untrusted_context>
52

grep_search command

+26:06
Recorded reasoning summary 30 words

Analyzing Model Configuration

I'm currently scrutinizing train_current_model.py, specifically questioning the values set for Config.uniform_negatives and Config.inbatch_negatives. The presence of command-line options in this script is also a point of investigation.

Tool callgrep_searchTool call Returned

Tool call · Input

{
  "pattern": "add_argument.*negative",
  "dir_path": "/app/solution",
  "include_pattern": "train_current_model.py"
}

Tool response

No matches found for pattern "add_argument.*negative" in path "/app/solution" (filter: "train_current_model.py").
53

Backup original train_current_model.py

+26:51
Recorded reasoning summary 44 words

Clarifying Argument Parsing

I'm reviewing the argument parsing logic, specifically noting that --uniform-negatives and --inbatch-negatives aren't registered parameters. I'm focusing on the add_argument calls to confirm only --negative-filter-scope is present, and examining the Config instantiation in main() to understand how these configurations are handled.

Recorded reasoning summary 47 words

Investigating Configuration Loading

I've identified that several configuration parameters, like uniform_negatives and inbatch_negatives, are defined within the Config class but are not exposed as command-line arguments. My current focus is on how these internal Config settings are populated and utilized, as they aren't directly mapped from args.

Recorded reasoning summary 52 words

Analyzing Negative Sampling

I'm now delving into how negative examples are utilized within the corrected_negative_loss function of the current trainer. My aim is to pinpoint limitations in the existing negative-sampling strategy, hypothesize potential improvements, and then validate these changes against the public backtest, all while respecting the CPU budget and serving contracts.

Recorded reasoning summary 42 words

Refining Negative Loss Calculation

I'm scrutinizing the corrected_negative_loss function and its interaction with score_target_microbatches. My focus is on how uniform_negatives and inbatch_negatives are weighted and applied, specifically examining the division by total and the clamp_min for stability, to ensure accurate loss computation.

Recorded reasoning summary 47 words

Adjusting Loss Weights

I'm analyzing the impact of current loss calculations. The ratio of positive to negative item weighting is severely skewed, with positives having 32 times more influence. This imbalance is critically hindering effective retrieval training, prompting an urgent need to re-evaluate and rebalance these weights.

Recorded reasoning summary 49 words

Revising Loss Strategy

I'm questioning the fundamental approach to negative loss in BCE. The tendency to simply amplify popular item embeddings is problematic as it doesn't effectively push down false positives. I'm considering alternative loss functions like InfoNCE for retrieval, or re-evaluating how negative loss is scaled within BCE.

Recorded reasoning summary 40 words

Exploring InfoNCE Properties

I'm investigating the mathematical underpinnings of InfoNCE, particularly its gradient behavior with respect to hard negatives and how its structure inherently addresses the positive/negative loss balancing issue. I'm also considering the implications of the temperature parameter $\tau$.

Recorded reasoning summary 47 words

Analyzing InfoNCE Gradient

I'm examining how InfoNCE's gradient behaves with hard negatives and its inherent balance of positive/negative loss, considering the impact of the temperature parameter $\tau$. My research suggests that InfoNCE naturally avoids popularity collapse by adjusting logits based on item popularity, leading to better retrieval.

Recorded reasoning summary 46 words

Evaluating Embedding Normalization

I'm considering normalizing embeddings or using cosine similarity for better logit ranges, as current dot products are limited. However, the serving contract uses raw dot products in rank_candidates, creating a constraint. I need to reconcile this with the potential benefits of normalized representations.

Recorded reasoning summary 39 words

Investigating Negative Selection

I'm now examining how negatives are drawn, specifically questioning the origin of uniform_negatives and inbatch_negatives. My focus is on understanding the selection process for these negatives, considering the implications for retrieval model training and potential biases.

Recorded reasoning summary 50 words

Exploring Negative Sampling Strategy

I'm analyzing the impact of negative sampling methods. Uniform negatives, often tail tracks, provide trivial distinctions, leading to coarse popularity learning. In-batch negatives, however, force finer distinctions by contrasting listened songs, thus teaching nuanced preferences. I am now exploring alternative ratios and sampling pools for negatives.

Recorded reasoning summary 51 words

Analyzing In-Batch Negative Sampling

I'm digging into how in-batch negatives were implemented, specifically questioning the use of torch.unique on targets. This seems to limit unique_targets to each song appearing only once per batch, which feels off for generating diverse in-batch negatives. I'm exploring the impact of this on the sampling process.

Recorded reasoning summary 42 words

Correcting In-Batch Sampling

I've discovered the in-batch negative sampling implementation is fundamentally flawed. It uniformly samples from unique targets, negating the intended proportional sampling based on listen counts. This needs immediate correction to reflect the true definition and purpose of in-batch negatives.

Recorded reasoning summary 48 words

Correcting Loss Weighting

I've identified a critical flaw where popular items were uniformly sampled as negatives and their loss contribution was significantly downweighted. This made them effectively immune to loss penalties, leading to the model's inability to properly learn from them. I'm now focused on rectifying this imbalance.

Recorded reasoning summary 49 words

Revising Importance Sampling Logic

I'm realizing the baseline's attempt to estimate uniform negative loss using in-batch negatives was fundamentally flawed. The prior implementation's weighting scheme incorrectly inverted the importance sampling principle, aiming to treat naturally hard, popular in-batch negatives as if they were uniformly sampled. This needs complete correction.

Recorded reasoning summary 52 words

Correcting Baseline Strategy

My realization is that the baseline attempted to use all negatives (24 uniform + 8 in-batch) to simulate uniform random sampling. This means 99% of these negatives were unlistened tail items, which leads models to only learn to recommend the globally most popular items, explaining the observed recommendation pattern.

Recorded reasoning summary 43 words

Testing In-Batch Negatives

I'm now investigating the impact of not downweighting in-batch negatives by $1/p(x)$. My focus is on treating these in-batch negatives as hard negatives, considering the common practice in recommendation systems like YouTube and Spotify, where their real-world listenership is key.

Recorded reasoning summary 41 words

Testing In-Batch Negatives

I'm investigating how not downweighting in-batch negatives by $1/p(x)$ impacts performance. My focus is on treating these as hard negatives, aligning with practices in systems like YouTube and Spotify where real-world listenership is crucial for effective contrastive learning.

Recorded reasoning summary 47 words

Revising Validation Logic

I'm realizing the validation metric must align with the training loss for effective checkpoint selection. If I train with InfoNCE or a modified BCE, the evaluate_validation_bce function needs to reflect that, otherwise, early stopping decisions will be flawed and my model performance will suffer.

Tool callrun_shell_commandBackup original train_current_model.py Returned

Tool call · Input

{
  "description": "Backup original train_current_model.py",
  "command": "cp /app/solution/train_current_model.py /app/solution/train_current_model_baseline.py"
}

Tool response

<untrusted_context>
Output: (empty)
Process Group PGID: 1991
</untrusted_context>
54

read_file train_current_model.py

+28:31
Recorded reasoning summary 37 words

Refining Negative Sampling

I'm currently diving into train_current_model.py to explore modifications in negative sampling, specifically focusing on the draw_full_history_filtered_negatives function. My next step is to test different approaches here to see how they impact the model's performance.

Recorded reasoning summary 44 words

Adjusting Negative Sampling Ratios

I'm experimenting with flipping the ratios of uniform vs. in-batch negatives. Additionally, I'm considering sampling in-batch negatives directly from targets_cpu for a frequency-based approach, and evaluating the impact of removing the item_correction downweighting on in-batch negatives within the corrected_negative_loss function.

Recorded reasoning summary 46 words

Revising Loss Calculation

I'm reassessing how popular items are handled in negative sampling. By removing the downweighting on popular items when sampling in-batch negatives, I'm aiming to ensure they're penalized more effectively. I'm also exploring if InfoNCE or cross-entropy loss would be a more suitable framework.

Recorded reasoning summary 38 words

Evaluating InfoNCE Implementation

I've realized the elegance of InfoNCE directly using F.cross_entropy. This method naturally handles positive and negative logits without arbitrary separation, ensuring that a single strong negative can significantly influence the gradient. The simplicity is striking.

Recorded reasoning summary 48 words

Exploring Temperature Scaling

I'm now focused on the temperature parameter $\tau$ in the InfoNCE loss. It appears to inherently perform hard negative mining. I'm investigating optimal values, considering the norms of our embeddings and common practices in related retrieval models like CLIP, potentially ranging from 0.05 to 0.2.

Recorded reasoning summary 45 words

Testing LogQ Correction

I'm now considering logQ correction within the InfoNCE framework, inspired by sampling-bias correction. This involves subtracting the log of an item's sampling probability from its logit. I'm eager to test how this impacts personalized ranking at inference time, moving beyond simple popularity.

Recorded reasoning summary 42 words

Adding Configuration Options

I'm planning to integrate CLI arguments and configuration options to manage loss types, temperatures, negative sampling strategies, and target weighting. My immediate task is to update train_current_model.py to accommodate these parameters for streamlined experimentation and robust public NDCG measurement.

Recorded reasoning summary 126 words

Adding Configuration Options

I'm planning to integrate CLI arguments and configuration options to manage loss types, temperatures, negative sampling strategies, and target weighting. My immediate task is to update train_current_model.py to accommodate these parameters for streamlined experimentation and robust public NDCG measurement.

Implementing Configuration Parameters

I've started integrating new CLI arguments into main() for loss type, temperature, uniform and in-batch negative counts, and in-batch sampling frequency. This will allow for more flexible and systematic testing of different configurations, making it easier to manage hyperparameters.

Analyzing Score Target Microbatches

I am now scrutinizing the score_target_microbatches function to understand its loss and gradient computation. My goal is to ensure these newly added configuration parameters are correctly integrated into the existing loss calculation logic, ensuring accurate and efficient training.

Recorded reasoning summary 44 words

Validating Gradient Flow

I am now examining the score_target_microbatches function, specifically how loss and gradients are computed within its microbatches. My focus is on confirming the seamless integration of the new configuration parameters into the existing loss calculation logic to ensure precision and efficiency.

Recorded reasoning summary 46 words

Validating Microbatch Logic

I'm currently stepping through score_target_microbatches to verify how the loss and gradients are calculated within these segments. My primary concern is confirming that the new configuration parameters integrate correctly into the existing loss computation pipeline, ensuring everything flows as expected for precise training.

Recorded reasoning summary 42 words

Verifying Microbatch Gradient Flow

I'm meticulously reviewing score_target_microbatches, tracing the loss and gradient computations within each microbatch. My immediate focus is confirming the correct integration of the new configuration parameters into the existing loss calculation pipeline to ensure accurate and efficient training.

Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "end_line": 1485,
  "file_path": "/app/solution/train_current_model.py",
  "start_line": 1364
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 1364-1485 of 2165 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 1486.

--- FILE CONTENT (truncated) ---
def evaluate_validation_bce(
    model: base.SequentialTwoTower,
    prepared: SequenceData,
    config: Config,
    target_weights: np.ndarray,
    window_starts: np.ndarray,
    training_counts: np.ndarray,
    validation_counts: np.ndarray,
    item_correction: torch.Tensor,
    known_positive_packed: np.ndarray | None,
    device: torch.device,
) -> dict[str, float]:
    """Measure deterministic BCE on each user's chronological target suffix."""
    model.eval()
    totals = training_counts + validation_counts
    users_with_validation = np.flatnonzero(validation_counts > 0)
    ordered = users_with_validation[
        np.argsort(totals[users_with_validation], kind="stable")
    ]
    groups = [
        ordered[start : start + config.user_batch_size]
        for start in range(0, len(ordered), config.user_batch_size)
    ]
    generator = torch.Generator(device="cpu").manual_seed(config.seed + 20_000)
    total_loss = 0.0
    total_targets = 0
    total_weight = 0.0
    started = time.monotonic()

    for group_number, users in enumerate(groups, start=1):
        group_totals = totals[users]
        group_starts = training_counts[users]
        hidden = torch.zeros(
            1, len(users), config.embedding_dim, device=device
        )
        max_targets = int(group_totals.max())
        for start in range(0, max_targets, config.bptt_steps):
            steps = min(config.bptt_steps, max_targets - start)
            block = build_dense_block(
                prepared,
                target_weights,
                users,
                window_starts[users],
                group_totals,
                group_starts,
                start,
                steps,
                config,
            )
            sequence_outputs, _ = event_sequence(
                model,
                torch.from_numpy(block[0].astype(np.int64)).to(device),
                torch.from_numpy(block[1].astype(np.float32)).to(device),
                hidden,
            )
            hidden = torch.stack(
                [
                    sequence_outputs[row, count - 1]
                    if count
                    else hidden[0, row]
                    for row, count in enumerate(block[7])
                ]
            ).unsqueeze(0)
            flat_scored = block[5].reshape(-1)
            if not np.any(flat_scored):
                continue
            mask = torch.from_numpy(flat_scored).to(device)
            sequence_vectors = sequence_outputs.reshape(
                -1, config.embedding_dim
            )[mask]
            flat_states = block[3].reshape(-1)[flat_scored]
            positive_items = torch.from_numpy(
                block[4].reshape(-1)[flat_scored].astype(np.int64)
            ).to(device)
            known_history = torch.from_numpy(
                block[6].reshape(-1, config.bptt_steps)[flat_scored].astype(
                    np.int64
                )
            ).to(device)
            liked_items = torch.from_numpy(
                prepared.liked_states[flat_states].astype(np.int64)
            ).to(device)
            flat_user_rows = np.broadcast_to(
                users[:, None], block[5].shape
            ).reshape(-1)[flat_scored]
            negatives, negative_weights = draw_training_negatives(
                positive_items,
                known_history,
                liked_items,
                flat_user_rows,
                known_positive_packed,
                prepared,
                config,
                item_correction,
                generator,
                device,
            )
            statistics, _ = score_target_microbatches(
                model,
                prepared,
                config,
                sequence_vectors,
                flat_states,
                block[2].reshape(-1, 4)[flat_scored].astype(np.float32),
                positive_items,
                negatives,
                negative_weights,
                block[8].reshape(-1)[flat_scored],
                device,
                backward=False,
            )
            total_loss += statistics["loss_sum"]
            total_targets += len(positive_items)
            total_weight += statistics["weight_sum"]
        if group_number % 25 == 0:
            release_accelerator_cache(device)
    return {
        "validation_loss": total_loss / max(total_weight, 1.0e-12),
        "validation_targets": float(total_targets),
        "validation_target_weight_sum": total_weight,
        "validation_seconds": time.monotonic() - started,
    }
55

read_file train_current_model.py

+28:56
Recorded reasoning summary 44 words

Confirming Validation Loss Calculation

I've confirmed that the evaluate_validation_bce function directly calculates the validation loss by calling score_target_microbatches with backward=False. This means the validation loss is being accurately determined during the evaluation phase. My next step is to examine the item_correction and logging mechanisms.

Recorded reasoning summary 36 words

Investigating Item Correction Logic

I'm now analyzing the build_item_correction function. My current focus is on how it estimates in-batch propensities. I'm tracing the calculation of counts and probabilities to understand its contribution to the model's behavior.

Recorded reasoning summary 51 words

Analyzing In-batch Correction

I'm scrutinizing the in-batch correction logic. It appears the probabilities used are derived from the overall target item probabilities across the training corpus. I'm comparing this approach to Google's Sampled Softmax with LogQ correction, specifically examining how positive and candidate item logits are adjusted based on these probabilities.

Recorded reasoning summary 52 words

Exploring Loss Function Variations

I'm now considering switching to InfoNCE for evaluation to better understand its behavior without the complexities of logQ correction. I'm also reviewing the configuration parameters that will be needed to support these different loss functions, including temperature, negative sampling strategies, and weighting schemes, to ensure flexibility and comparability.

Recorded reasoning summary 40 words

Refining Target Sampling

I'm re-examining how in-batch targets are sampled. The current approach draws randomly from all unique targets. I'm now considering an alternative where inbatch is sampled directly from the targets_cpu for each row, potentially improving efficiency and relevance.

Recorded reasoning summary 46 words

Simplifying Target Sampling

I've identified a more efficient method for sampling in-batch targets. By directly sampling from targets_cpu, items with higher frequency within the batch naturally become more probable to be selected. This also eliminates significant tensor allocation and processing steps, streamlining the entire pipeline considerably.

Recorded reasoning summary 45 words

Refining Negative Sampling

I'm now focusing on the logic for handling rejected negative items. It seems rejected items are replaced with random catalog items uniformly. I'm considering making the number of in-batch versus uniform negatives configurable via CLI arguments to further tune the sampling strategy.

Recorded reasoning summary 46 words

Configuring Negative Sampling

I'm now looking at how negative items are handled. It appears rejected items are being replaced with random catalog items uniformly. I plan to make the ratio of in-batch to uniform negatives a configurable parameter via CLI arguments to better control this aspect.

Recorded reasoning summary 47 words

Implementing Loss Function Logic

I'm now integrating the logic for the InfoNCE loss function. This involves correctly calculating scaled logits and applying cross-entropy. I'm also preparing to expose new CLI arguments for loss type, temperature, and negative sampling configurations to provide greater control over the evaluation process.

Recorded reasoning summary 57 words

Integrating InfoNCE and LogQ

I'm now integrating the logic for the InfoNCE loss function, specifically focusing on how logQ correction is computed for both positive and negative items. My observation is that while loss_sum is calculated using InfoNCE cross-entropy, the positive_sum, negative_sum, pair_correct, and weight_sum statistics remain identical across different loss calculations, which I need to verify.

Recorded reasoning summary 47 words

Considering BPR Loss

I'm now exploring the BPR loss function as an alternative to InfoNCE. It appears to directly penalize when negative logits exceed positive logits, offering a different approach to ranking optimization. I'm evaluating how its formulation and resulting loss calculation might compare to current methods.

Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "file_path": "/app/solution/train_current_model.py",
  "start_line": 40,
  "end_line": 75
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 40-75 of 2165 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 76.

--- FILE CONTENT (truncated) ---
@dataclass(frozen=True)
class Config:
    bptt_steps: int = 100
    user_batch_size: int = 64
    embedding_dim: int = 192
    hidden_dim: int = 192
    user_hidden_1: int = 512
    user_hidden_2: int = 256
    item_hidden_1: int = 512
    item_hidden_2: int = 256
    dropout: float = 0.05
    epochs: int = 1
    learning_rate: float = 1.0e-3
    weight_decay: float = 1.0e-5
    gradient_clip: float = 2.0
    loss_microbatch_size: int = 65_536
    uniform_negatives: int = 24
    inbatch_negatives: int = 8
    inbatch_correction_power: float = 0.5
    inbatch_correction_min: float = 0.25
    inbatch_correction_max: float = 4.0
    negative_filter_scope: str = "full-training-history"
    target_weighting: str = "organic-strong"
    ordinary_target_weight: float = 0.25
    organic_strong_target_weight: float = 1.0
    organic_like_target_weight: float = 3.0
    discovery_horizon_days: int = 7
    validation_fraction: float = 0.10
    max_train_targets_per_user: int = 128
    max_validation_targets_per_user: int = 16
    early_stopping_patience: int = 1
    early_stopping_min_delta: float = 1.0e-4
    seed: int = 29


@dataclass(frozen=True)
56

read_file train_current_model.py

+29:00
Recorded reasoning summary 24 words

Refining Configuration Options

I'm considering adding loss_type, temperature, and inbatch_frequency_sample to our Config. I'm also exploring the potential impact of introducing an inbatch_correction_power parameter.

Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "end_line": 1990,
  "start_line": 1925,
  "file_path": "/app/solution/train_current_model.py"
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 1925-1990 of 2165 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 1991.

--- FILE CONTENT (truncated) ---
        "--stage", choices=("validation", "submission"), default="validation"
    )
    parser.add_argument("--output", type=Path, required=True)
    parser.add_argument("--public-dir", type=Path, required=True)
    parser.add_argument("--prepared-cache", type=Path)
    parser.add_argument("--device", choices=("cpu", "mps"), default="cpu")
    parser.add_argument("--threads", type=int, default=8)
    parser.add_argument("--bptt-steps", type=int, default=Config.bptt_steps)
    parser.add_argument(
        "--user-batch-size", type=int, default=Config.user_batch_size
    )
    parser.add_argument("--epochs", type=int, default=Config.epochs)
    parser.add_argument("--learning-rate", type=float, default=Config.learning_rate)
    parser.add_argument(
        "--loss-microbatch-size",
        type=int,
        default=Config.loss_microbatch_size,
    )
    parser.add_argument(
        "--negative-filter-scope",
        choices=("full-training-history", "last-100"),
        default=Config.negative_filter_scope,
    )
    parser.add_argument(
        "--target-weighting",
        choices=("discovery-graded", "organic-strong", "uniform"),
        default=Config.target_weighting,
    )
    parser.add_argument(
        "--ordinary-target-weight",
        type=float,
        default=Config.ordinary_target_weight,
    )
    parser.add_argument(
        "--organic-strong-target-weight",
        type=float,
        default=Config.organic_strong_target_weight,
    )
    parser.add_argument(
        "--organic-like-target-weight",
        type=float,
        default=Config.organic_like_target_weight,
    )
    parser.add_argument(
        "--discovery-horizon-days",
        type=int,
        default=Config.discovery_horizon_days,
    )
    parser.add_argument(
        "--validation-fraction",
        type=float,
        default=Config.validation_fraction,
    )
    parser.add_argument(
        "--max-train-targets-per-user",
        type=int,
        default=Config.max_train_targets_per_user,
        help="retain this many recent pre-validation targets per user; 0 is uncapped",
    )
    parser.add_argument(
        "--max-validation-targets-per-user",
        type=int,
        default=Config.max_validation_targets_per_user,
        help="retain this many final validation targets per user; 0 is uncapped",
    )
    parser.add_argument(
57

read_file train_current_model.py

+29:11
Recorded reasoning summary 34 words

Considering Loss Function Options

I'm currently exploring the inclusion of different loss function types in main(), specifically evaluating options like "bce", "infonce", "infonce-logq", and "bpr". I'm also looking at integrating a configurable temperature parameter.

Recorded reasoning summary 40 words

Implementing In-Batch Negatives

I'm now focusing on the practical implementation of in-batch negative sampling, particularly the draw_full_history_filtered_negatives function. I'm examining the conditional logic when config.inbatch_frequency_sample is enabled, and how this interacts with the calculation of corrected_count and subsequent priority sampling.

Recorded reasoning summary 35 words

Refining In-Batch Sampling

I've successfully refactored the in-batch negative sampling logic. When inbatch_frequency_sample is active, I'm now directly sampling from targets_cpu, which significantly boosts performance. This approach bypasses the previous, slower priorities.masked_fill_ and torch.topk operations.

Recorded reasoning summary 36 words

Analyzing Score Calculation

I'm currently analyzing the score_target_microbatches function, specifically how it computes positive_logits and negative_logits. I'm investigating the conditional logic for "infonce" and "bpr" loss types and their integration with temperature scaling and cross-entropy calculations.

Recorded reasoning summary 38 words

Evaluating Infonce Loss

I am currently dissecting the infonce loss calculation, specifically scrutinizing how all_logits is constructed and what constitutes negative_logits. My focus is on the implications of all_logits concatenating positive logits with negative_logits of shape (B, K).

Recorded reasoning summary 49 words

Adjusting infonce-logq Logic

I've noticed an oversight in my previous analysis of infonce-logq loss. I was not accounting for the negative_weights correctly, which are already being passed and applied to the score calculation based on the correction logic. I need to re-evaluate the direct impact of these pre-computed weights.

Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "start_line": 150,
  "file_path": "/app/solution/train_current_model.py",
  "end_line": 170
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 150-170 of 2165 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 171.

--- FILE CONTENT (truncated) ---
def model_config(config: Config) -> base.TowerConfig:
    """Map the dense trainer configuration onto the unchanged tower."""
    return base.TowerConfig(
        sequence_length=config.bptt_steps,
        embedding_dim=config.embedding_dim,
        hidden_dim=config.hidden_dim,
        user_hidden_1=config.user_hidden_1,
        user_hidden_2=config.user_hidden_2,
        item_hidden_1=config.item_hidden_1,
        item_hidden_2=config.item_hidden_2,
        dropout=config.dropout,
        epochs=config.epochs,
        learning_rate=config.learning_rate,
        weight_decay=config.weight_decay,
        gradient_clip=config.gradient_clip,
        uniform_negatives=config.uniform_negatives,
        inbatch_negatives=config.inbatch_negatives,
        inbatch_correction_power=config.inbatch_correction_power,
        inbatch_correction_min=config.inbatch_correction_min,
        inbatch_correction_max=config.inbatch_correction_max,
        seed=config.seed,
58

read_file train_current_model.py

+29:17
Recorded reasoning summary 30 words

Exploring Model Configuration

I'm currently examining how model_config instantiates base.TowerConfig, specifically noting the parameters like uniform_negatives and inbatch_negatives being passed. This detail seems crucial for understanding the underlying configuration mechanics.

Recorded reasoning summary 37 words

Implementing Loss Variants

I'm now focused on integrating new loss functionalities. This involves defining loss_type and temperature parameters, and expanding score_target_microbatches to support InfoNCE, BPR, and BCE. Additionally, I'll be addressing the inbatch_frequency_sample flag and its impact.

Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "end_line": 80,
  "start_line": 40,
  "file_path": "/app/solution/train_current_model.py"
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 40-80 of 2165 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 81.

--- FILE CONTENT (truncated) ---
@dataclass(frozen=True)
class Config:
    bptt_steps: int = 100
    user_batch_size: int = 64
    embedding_dim: int = 192
    hidden_dim: int = 192
    user_hidden_1: int = 512
    user_hidden_2: int = 256
    item_hidden_1: int = 512
    item_hidden_2: int = 256
    dropout: float = 0.05
    epochs: int = 1
    learning_rate: float = 1.0e-3
    weight_decay: float = 1.0e-5
    gradient_clip: float = 2.0
    loss_microbatch_size: int = 65_536
    uniform_negatives: int = 24
    inbatch_negatives: int = 8
    inbatch_correction_power: float = 0.5
    inbatch_correction_min: float = 0.25
    inbatch_correction_max: float = 4.0
    negative_filter_scope: str = "full-training-history"
    target_weighting: str = "organic-strong"
    ordinary_target_weight: float = 0.25
    organic_strong_target_weight: float = 1.0
    organic_like_target_weight: float = 3.0
    discovery_horizon_days: int = 7
    validation_fraction: float = 0.10
    max_train_targets_per_user: int = 128
    max_validation_targets_per_user: int = 16
    early_stopping_patience: int = 1
    early_stopping_min_delta: float = 1.0e-4
    seed: int = 29


@dataclass(frozen=True)
class CandidateSet:
    uids: np.ndarray
    item_ids: np.ndarray
    packed: np.ndarray
59

read_file train_current_model.py

+29:20
Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "end_line": 685,
  "file_path": "/app/solution/train_current_model.py",
  "start_line": 645
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 645-685 of 2165 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 686.

--- FILE CONTENT (truncated) ---
    uniform = torch.randint(
        n_items,
        (batch_size, config.uniform_negatives),
        generator=generator,
        device="cpu",
    )
    inbatch = torch.empty((batch_size, 0), dtype=torch.long)
    corrected_count = 0
    if config.inbatch_negatives:
        unique_targets = torch.unique(targets.detach().cpu())
        corrected_count = min(
            config.inbatch_negatives, max(len(unique_targets) - 1, 0)
        )
        if corrected_count:
            priorities = torch.rand(
                (batch_size, len(unique_targets)), generator=generator
            )
            priorities.masked_fill_(
                unique_targets[None, :].eq(
                    torch.from_numpy(targets_cpu)[:, None]
                ),
                -1.0,
            )
            columns = torch.topk(
                priorities, k=corrected_count, dim=1
            ).indices
            inbatch = unique_targets[columns]
        if corrected_count < config.inbatch_negatives:
            filler = torch.randint(
                n_items,
                (batch_size, config.inbatch_negatives - corrected_count),
                generator=generator,
                device="cpu",
            )
            inbatch = torch.cat([inbatch, filler], dim=1)

    negatives = torch.cat([uniform, inbatch], dim=1).numpy()
    correction = np.ones_like(negatives, dtype=np.float32)
    if corrected_count:
        correction[
            :, config.uniform_negatives : config.uniform_negatives + corrected_count
60

read_file train_current_model.py

+29:23
Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "file_path": "/app/solution/train_current_model.py",
  "start_line": 1160,
  "end_line": 1195
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 1160-1195 of 2165 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 1196.

--- FILE CONTENT (truncated) ---
            torch.from_numpy(numeric).to(device),
        )
        positive_vectors, negative_vectors = candidate_vectors(
            model,
            positive_items[begin:end],
            negatives[begin:end],
        )
        positive_logits = (query_vectors * positive_vectors).sum(dim=1)
        negative_logits = torch.einsum(
            "bd,bkd->bk", query_vectors, negative_vectors
        )
        positive_loss = F.softplus(-positive_logits)
        negative_loss = corrected_negative_loss(
            negative_logits, negative_weights[begin:end], config
        )
        selected_weights = torch.from_numpy(
            sample_weights[begin:end].astype(np.float32, copy=False)
        ).to(device)
        loss_sum = (
            selected_weights * (positive_loss + negative_loss) / 2.0
        ).sum()
        if not bool(torch.isfinite(loss_sum)):
            raise RuntimeError("dense next-item training produced non-finite loss")
        if backward:
            (loss_sum / total_weight).backward()
            if sequence_input.grad is None:
                raise RuntimeError("sequence microbatch did not produce a gradient")
            sequence_gradient[begin:end] = sequence_input.grad
        statistics["loss_sum"] += float(loss_sum.detach().cpu())
        statistics["positive_sum"] += float(positive_logits.detach().sum().cpu())
        statistics["negative_sum"] += float(negative_logits.detach().sum().cpu())
        statistics["pair_correct"] += float(
            (positive_logits.detach()[:, None] > negative_logits.detach()).sum().cpu()
        )
        statistics["weight_sum"] += float(selected_weights.sum().detach().cpu())
    return statistics, sequence_gradient
61

read_file train_current_model.py

+29:25
Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "end_line": 2050,
  "file_path": "/app/solution/train_current_model.py",
  "start_line": 1935
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 1935-2050 of 2165 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 2051.

--- FILE CONTENT (truncated) ---
    )
    parser.add_argument("--epochs", type=int, default=Config.epochs)
    parser.add_argument("--learning-rate", type=float, default=Config.learning_rate)
    parser.add_argument(
        "--loss-microbatch-size",
        type=int,
        default=Config.loss_microbatch_size,
    )
    parser.add_argument(
        "--negative-filter-scope",
        choices=("full-training-history", "last-100"),
        default=Config.negative_filter_scope,
    )
    parser.add_argument(
        "--target-weighting",
        choices=("discovery-graded", "organic-strong", "uniform"),
        default=Config.target_weighting,
    )
    parser.add_argument(
        "--ordinary-target-weight",
        type=float,
        default=Config.ordinary_target_weight,
    )
    parser.add_argument(
        "--organic-strong-target-weight",
        type=float,
        default=Config.organic_strong_target_weight,
    )
    parser.add_argument(
        "--organic-like-target-weight",
        type=float,
        default=Config.organic_like_target_weight,
    )
    parser.add_argument(
        "--discovery-horizon-days",
        type=int,
        default=Config.discovery_horizon_days,
    )
    parser.add_argument(
        "--validation-fraction",
        type=float,
        default=Config.validation_fraction,
    )
    parser.add_argument(
        "--max-train-targets-per-user",
        type=int,
        default=Config.max_train_targets_per_user,
        help="retain this many recent pre-validation targets per user; 0 is uncapped",
    )
    parser.add_argument(
        "--max-validation-targets-per-user",
        type=int,
        default=Config.max_validation_targets_per_user,
        help="retain this many final validation targets per user; 0 is uncapped",
    )
    parser.add_argument(
        "--early-stopping-patience",
        type=int,
        default=Config.early_stopping_patience,
    )
    parser.add_argument(
        "--early-stopping-min-delta",
        type=float,
        default=Config.early_stopping_min_delta,
    )
    parser.add_argument("--checkpoint-dir", type=Path)
    parser.add_argument("--resume-checkpoint", type=Path)
    parser.add_argument("--seed", type=int, default=Config.seed)
    parser.add_argument("--ranking-batch-size", type=int, default=64)
    parser.add_argument("--prepare-only", action="store_true")
    args = parser.parse_args()

    if args.threads < 1 or args.bptt_steps < 2 or args.user_batch_size < 1:
        parser.error("threads, BPTT steps, and user batch size must be positive")
    if (
        args.epochs < 1
        or args.learning_rate <= 0
        or args.loss_microbatch_size < 1
        or args.early_stopping_patience < 1
        or args.early_stopping_min_delta < 0
        or args.ordinary_target_weight <= 0
        or args.organic_strong_target_weight <= 0
        or args.organic_like_target_weight <= 0
        or args.discovery_horizon_days < 1
        or args.max_train_targets_per_user < 0
        or args.max_validation_targets_per_user < 0
    ):
        parser.error("training counts, learning rate, and patience are invalid")
    if not 0.0 < args.validation_fraction < 1.0:
        parser.error("validation fraction must be strictly between zero and one")
    public = args.public_dir.resolve()
    if not (public / "data" / "candidate_catalog.parquet").is_file():
        parser.error(f"public task data not found under {public}")
    config = Config(
        bptt_steps=args.bptt_steps,
        user_batch_size=args.user_batch_size,
        epochs=args.epochs,
        learning_rate=args.learning_rate,
        loss_microbatch_size=args.loss_microbatch_size,
        negative_filter_scope=args.negative_filter_scope,
        target_weighting=args.target_weighting,
        ordinary_target_weight=args.ordinary_target_weight,
        organic_strong_target_weight=args.organic_strong_target_weight,
        organic_like_target_weight=args.organic_like_target_weight,
        discovery_horizon_days=args.discovery_horizon_days,
        validation_fraction=args.validation_fraction,
        max_train_targets_per_user=args.max_train_targets_per_user,
        max_validation_targets_per_user=args.max_validation_targets_per_user,
        early_stopping_patience=args.early_stopping_patience,
        early_stopping_min_delta=args.early_stopping_min_delta,
        seed=args.seed,
    )
    torch.set_num_threads(args.threads)
    torch.set_num_interop_threads(1)
    seed_everything(config.seed)
    device = torch.device(args.device)
62

replace train_current_model.py

+29:39
Recorded reasoning summary 46 words

Exploring Configuration Options

I'm currently examining the Config and args definitions. Specifically, I'm focusing on how the loss_type parameter is handled, noting its default value and available choices as provided in the arguments. This helps me understand the flexibility and current settings for this critical component.

Recorded reasoning summary 29 words

Investigating Negative Sampling

My focus has shifted to the draw_full_history_filtered_negatives function. I'm analyzing its handling of in-batch negatives, specifically how config.inbatch_negatives and config.inbatch_frequency_sample influence the generation of negative samples.

Recorded reasoning summary 60 words

Refining Negative Sampling Logic

I'm deep into the draw_full_history_filtered_negatives function, specifically the part that calculates corrected_count. I'm looking at how it uses config.inbatch_negatives and the number of unique targets to determine the actual number of in-batch negatives, ensuring it doesn't exceed available unique targets. I'm also tracing how it then generates those inbatch samples and handles any remaining filler negatives.

Recorded reasoning summary 40 words

Analyzing Loss Calculation

I'm now scrutinizing the score_target_microbatches function, particularly how different config.loss_type values like "infonce" and "bpr" impact logit calculations and cross-entropy losses. I'm tracing how positive and negative logits are combined and scaled with temperature before loss computation.

Tool callreplace/app/solution/train_current_model.py Error

Tool call · Input

{
  "old_string": "    early_stopping_patience: int = 1\n    early_stopping_min_delta: float = 1.0e-4\n    seed: int = 29",
  "new_string": "    early_stopping_patience: int = 1\n    early_stopping_min_delta: float = 1.0e-4\n    seed: int = 29\n    loss_type: str = \"bce\"\n    temperature: float = 0.1\n    inbatch_frequency_sample: bool = False",
  "file_path": "/app/solution/train_current_model.py",
  "instruction": "Add loss_type, temperature, and inbatch_frequency_sample to Config"
}

Tool response · Tool error

EACCES: permission denied, open '/app/solution/train_current_model.py'
63

Check file permissions in /app/solution

+29:43
Tool callrun_shell_commandCheck file permissions in /app/solution Returned

Tool call · Input

{
  "command": "ls -la /app/solution",
  "description": "Check file permissions in /app/solution"
}

Tool response

<untrusted_context>
Output: total 1064568
drwxr-xr-x 1 agent agent      4096 Sep 29 01:48 .
drwxr-xr-x 1 agent agent      4096 Sep 29 01:18 ..
-r--r--r-- 1 agent agent      5774 Sep 29 01:22 evaluate_public.py
-rw-r--r-- 1 agent agent 552686232 Sep 29 01:40 prepared_sub.npz
-rw-r--r-- 1 agent agent 535225808 Sep 29 01:30 prepared_val.npz
-rw-r--r-- 1 agent agent   1244226 Sep 29 01:28 production_validation.parquet
-r--r--r-- 1 agent agent      8265 Sep 29 01:22 ranking_evaluation.py
-rw-r--r-- 1 agent agent    735840 Sep 29 01:40 submission.parquet
-r--r--r-- 1 agent agent     80058 Sep 29 01:22 train_current_model.py
-r--r--r-- 1 agent agent     80058 Sep 29 01:48 train_current_model_baseline.py
-r--r--r-- 1 agent agent     15985 Sep 29 01:22 two_tower_model.py
Process Group PGID: 1994
</untrusted_context>
64

Make files in /app/solution writable

+29:45
Tool callrun_shell_commandMake files in /app/solution writable Returned

Tool call · Input

{
  "description": "Make files in /app/solution writable",
  "command": "chmod -R u+w /app/solution"
}

Tool response

<untrusted_context>
Output: (empty)
Process Group PGID: 1997
</untrusted_context>
65

replace train_current_model.py

+29:50
Tool callreplace/app/solution/train_current_model.py Returned

Tool call · Input

{
  "instruction": "Add loss_type, temperature, and inbatch_frequency_sample to Config",
  "file_path": "/app/solution/train_current_model.py",
  "new_string": "    early_stopping_patience: int = 1\n    early_stopping_min_delta: float = 1.0e-4\n    seed: int = 29\n    loss_type: str = \"bce\"\n    temperature: float = 0.1\n    inbatch_frequency_sample: bool = False",
  "old_string": "    early_stopping_patience: int = 1\n    early_stopping_min_delta: float = 1.0e-4\n    seed: int = 29"
}

Tool response

Successfully modified file: /app/solution/train_current_model.py (1 replacements). Here is the updated code:
...
    max_train_targets_per_user: int = 128
    max_validation_targets_per_user: int = 16
    early_stopping_patience: int = 1
    early_stopping_min_delta: float = 1.0e-4
    seed: int = 29
    loss_type: str = "bce"
    temperature: float = 0.1
    inbatch_frequency_sample: bool = False


@dataclass(frozen=True)
class CandidateSet:
    uids: np.ndarray
...
66

read_file train_current_model.py

+29:56
Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "start_line": 650,
  "end_line": 685,
  "file_path": "/app/solution/train_current_model.py"
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 650-685 of 2168 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 686.

--- FILE CONTENT (truncated) ---
        (batch_size, config.uniform_negatives),
        generator=generator,
        device="cpu",
    )
    inbatch = torch.empty((batch_size, 0), dtype=torch.long)
    corrected_count = 0
    if config.inbatch_negatives:
        unique_targets = torch.unique(targets.detach().cpu())
        corrected_count = min(
            config.inbatch_negatives, max(len(unique_targets) - 1, 0)
        )
        if corrected_count:
            priorities = torch.rand(
                (batch_size, len(unique_targets)), generator=generator
            )
            priorities.masked_fill_(
                unique_targets[None, :].eq(
                    torch.from_numpy(targets_cpu)[:, None]
                ),
                -1.0,
            )
            columns = torch.topk(
                priorities, k=corrected_count, dim=1
            ).indices
            inbatch = unique_targets[columns]
        if corrected_count < config.inbatch_negatives:
            filler = torch.randint(
                n_items,
                (batch_size, config.inbatch_negatives - corrected_count),
                generator=generator,
                device="cpu",
            )
            inbatch = torch.cat([inbatch, filler], dim=1)

    negatives = torch.cat([uniform, inbatch], dim=1).numpy()
    correction = np.ones_like(negatives, dtype=np.float32)
67

replace train_current_model.py

+30:02
Tool callreplace/app/solution/train_current_model.py Returned

Tool call · Input

{
  "old_string": "    inbatch = torch.empty((batch_size, 0), dtype=torch.long)\n    corrected_count = 0\n    if config.inbatch_negatives:\n        unique_targets = torch.unique(targets.detach().cpu())\n        corrected_count = min(\n            config.inbatch_negatives, max(len(unique_targets) - 1, 0)\n        )\n        if corrected_count:\n            priorities = torch.rand(\n                (batch_size, len(unique_targets)), generator=generator\n            )\n            priorities.masked_fill_(\n                unique_targets[None, :].eq(\n                    torch.from_numpy(targets_cpu)[:, None]\n                ),\n                -1.0,\n            )\n            columns = torch.topk(\n                priorities, k=corrected_count, dim=1\n            ).indices\n            inbatch = unique_targets[columns]\n        if corrected_count < config.inbatch_negatives:\n            filler = torch.randint(\n                n_items,\n                (batch_size, config.inbatch_negatives - corrected_count),\n                generator=generator,\n                device=\"cpu\",\n            )\n            inbatch = torch.cat([inbatch, filler], dim=1)",
  "instruction": "Support inbatch_frequency_sample in draw_full_history_filtered_negatives",
  "new_string": "    inbatch = torch.empty((batch_size, 0), dtype=torch.long)\n    corrected_count = 0\n    if config.inbatch_negatives:\n        if config.inbatch_frequency_sample:\n            rand_indices = torch.randint(\n                len(targets_cpu),\n                (batch_size, config.inbatch_negatives),\n                generator=generator,\n                device=\"cpu\",\n            )\n            inbatch = torch.from_numpy(targets_cpu)[rand_indices]\n            corrected_count = config.inbatch_negatives\n        else:\n            unique_targets = torch.unique(targets.detach().cpu())\n            corrected_count = min(\n                config.inbatch_negatives, max(len(unique_targets) - 1, 0)\n            )\n            if corrected_count:\n                priorities = torch.rand(\n                    (batch_size, len(unique_targets)), generator=generator\n                )\n                priorities.masked_fill_(\n                    unique_targets[None, :].eq(\n                        torch.from_numpy(targets_cpu)[:, None]\n                    ),\n                    -1.0,\n                )\n                columns = torch.topk(\n                    priorities, k=corrected_count, dim=1\n                ).indices\n                inbatch = unique_targets[columns]\n            if corrected_count < config.inbatch_negatives:\n                filler = torch.randint(\n                    n_items,\n                    (batch_size, config.inbatch_negatives - corrected_count),\n                    generator=generator,\n                    device=\"cpu\",\n                )\n                inbatch = torch.cat([inbatch, filler], dim=1)",
  "file_path": "/app/solution/train_current_model.py"
}

Tool response

Successfully modified file: /app/solution/train_current_model.py (1 replacements). Here is the updated code:
...
        device="cpu",
    )
    inbatch = torch.empty((batch_size, 0), dtype=torch.long)
    corrected_count = 0
    if config.inbatch_negatives:
        if config.inbatch_frequency_sample:
            rand_indices = torch.randint(
                len(targets_cpu),
                (batch_size, config.inbatch_negatives),
                generator=generator,
                device="cpu",
            )
            inbatch = torch.from_numpy(targets_cpu)[rand_indices]
            corrected_count = config.inbatch_negatives
        else:
            unique_targets = torch.unique(targets.detach().cpu())
            corrected_count = min(
                config.inbatch_negatives, max(len(unique_targets) - 1, 0)
            )
            if corrected_count:
                priorities = torch.rand(
                    (batch_size, len(unique_targets)), generator=generator
                )
                priorities.masked_fill_(
                    unique_targets[None, :].eq(
                        torch.from_numpy(targets_cpu)[:, None]
                    ),
                    -1.0,
                )
                columns = torch.topk(
                    priorities, k=corrected_count, dim=1
                ).indices
                inbatch = unique_targets[columns]
            if corrected_count < config.inbatch_negatives:
                filler = torch.randint(
                    n_items,
                    (batch_size, config.inbatch_negatives - corrected_count),
                    generator=generator,
                    device="cpu",
                )
                inbatch = torch.cat([inbatch, filler], dim=1)

    negatives = torch.cat([uniform, inbatch], dim=1).numpy()
    correction = np.ones_like(negatives, dtype=np.float32)
    if corrected_count:
        correction[
...
68

read_file train_current_model.py

+30:06
Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "start_line": 1170,
  "end_line": 1205,
  "file_path": "/app/solution/train_current_model.py"
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 1170-1205 of 2178 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 1206.

--- FILE CONTENT (truncated) ---
            sequence_input,
            liked_vectors,
            disliked_vectors,
            torch.from_numpy(numeric).to(device),
        )
        positive_vectors, negative_vectors = candidate_vectors(
            model,
            positive_items[begin:end],
            negatives[begin:end],
        )
        positive_logits = (query_vectors * positive_vectors).sum(dim=1)
        negative_logits = torch.einsum(
            "bd,bkd->bk", query_vectors, negative_vectors
        )
        positive_loss = F.softplus(-positive_logits)
        negative_loss = corrected_negative_loss(
            negative_logits, negative_weights[begin:end], config
        )
        selected_weights = torch.from_numpy(
            sample_weights[begin:end].astype(np.float32, copy=False)
        ).to(device)
        loss_sum = (
            selected_weights * (positive_loss + negative_loss) / 2.0
        ).sum()
        if not bool(torch.isfinite(loss_sum)):
            raise RuntimeError("dense next-item training produced non-finite loss")
        if backward:
            (loss_sum / total_weight).backward()
            if sequence_input.grad is None:
                raise RuntimeError("sequence microbatch did not produce a gradient")
            sequence_gradient[begin:end] = sequence_input.grad
        statistics["loss_sum"] += float(loss_sum.detach().cpu())
        statistics["positive_sum"] += float(positive_logits.detach().sum().cpu())
        statistics["negative_sum"] += float(negative_logits.detach().sum().cpu())
        statistics["pair_correct"] += float(
            (positive_logits.detach()[:, None] > negative_logits.detach()).sum().cpu()
69

replace train_current_model.py

+30:11
Tool callreplace/app/solution/train_current_model.py Returned

Tool call · Input

{
  "new_string": "        positive_logits = (query_vectors * positive_vectors).sum(dim=1)\n        negative_logits = torch.einsum(\n            \"bd,bkd->bk\", query_vectors, negative_vectors\n        )\n        selected_weights = torch.from_numpy(\n            sample_weights[begin:end].astype(np.float32, copy=False)\n        ).to(device)\n        if config.loss_type == \"infonce\":\n            all_logits = torch.cat([positive_logits.unsqueeze(1), negative_logits], dim=1)\n            scaled = all_logits / config.temperature\n            target_indices = torch.zeros(len(scaled), dtype=torch.long, device=device)\n            sample_loss = F.cross_entropy(scaled, target_indices, reduction=\"none\")\n            loss_sum = (selected_weights * sample_loss).sum()\n        elif config.loss_type == \"bpr\":\n            diff = negative_logits - positive_logits.unsqueeze(1)\n            sample_loss = F.softplus(diff / config.temperature).mean(dim=1)\n            loss_sum = (selected_weights * sample_loss).sum()\n        else:\n            positive_loss = F.softplus(-positive_logits)\n            negative_loss = corrected_negative_loss(\n                negative_logits, negative_weights[begin:end], config\n            )\n            loss_sum = (\n                selected_weights * (positive_loss + negative_loss) / 2.0\n            ).sum()",
  "instruction": "Add infonce and bpr loss support to score_target_microbatches",
  "old_string": "        positive_logits = (query_vectors * positive_vectors).sum(dim=1)\n        negative_logits = torch.einsum(\n            \"bd,bkd->bk\", query_vectors, negative_vectors\n        )\n        positive_loss = F.softplus(-positive_logits)\n        negative_loss = corrected_negative_loss(\n            negative_logits, negative_weights[begin:end], config\n        )\n        selected_weights = torch.from_numpy(\n            sample_weights[begin:end].astype(np.float32, copy=False)\n        ).to(device)\n        loss_sum = (\n            selected_weights * (positive_loss + negative_loss) / 2.0\n        ).sum()",
  "file_path": "/app/solution/train_current_model.py"
}

Tool response

Successfully modified file: /app/solution/train_current_model.py (1 replacements). Here is the updated code:
...
        )
        positive_logits = (query_vectors * positive_vectors).sum(dim=1)
        negative_logits = torch.einsum(
            "bd,bkd->bk", query_vectors, negative_vectors
        )
        selected_weights = torch.from_numpy(
            sample_weights[begin:end].astype(np.float32, copy=False)
        ).to(device)
        if config.loss_type == "infonce":
            all_logits = torch.cat([positive_logits.unsqueeze(1), negative_logits], dim=1)
            scaled = all_logits / config.temperature
            target_indices = torch.zeros(len(scaled), dtype=torch.long, device=device)
            sample_loss = F.cross_entropy(scaled, target_indices, reduction="none")
            loss_sum = (selected_weights * sample_loss).sum()
        elif config.loss_type == "bpr":
            diff = negative_logits - positive_logits.unsqueeze(1)
            sample_loss = F.softplus(diff / config.temperature).mean(dim=1)
            loss_sum = (selected_weights * sample_loss).sum()
        else:
            positive_loss = F.softplus(-positive_logits)
            negative_loss = corrected_negative_loss(
                negative_logits, negative_weights[begin:end], config
            )
            loss_sum = (
                selected_weights * (positive_loss + negative_loss) / 2.0
            ).sum()
        if not bool(torch.isfinite(loss_sum)):
            raise RuntimeError("dense next-item training produced non-finite loss")
        if backward:
            (loss_sum / total_weight).backward()
            if sequence_input.grad is None:
...
70

read_file train_current_model.py

+30:14
Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "start_line": 1940,
  "file_path": "/app/solution/train_current_model.py",
  "end_line": 2070
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 1940-2070 of 2189 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 2071.

--- FILE CONTENT (truncated) ---
    elif output.suffix == ".csv":
        frame.to_csv(output, index=False)
    else:
        raise ValueError("--output must end in .parquet or .csv")


def main() -> int:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument(
        "--stage", choices=("validation", "submission"), default="validation"
    )
    parser.add_argument("--output", type=Path, required=True)
    parser.add_argument("--public-dir", type=Path, required=True)
    parser.add_argument("--prepared-cache", type=Path)
    parser.add_argument("--device", choices=("cpu", "mps"), default="cpu")
    parser.add_argument("--threads", type=int, default=8)
    parser.add_argument("--bptt-steps", type=int, default=Config.bptt_steps)
    parser.add_argument(
        "--user-batch-size", type=int, default=Config.user_batch_size
    )
    parser.add_argument("--epochs", type=int, default=Config.epochs)
    parser.add_argument("--learning-rate", type=float, default=Config.learning_rate)
    parser.add_argument(
        "--loss-microbatch-size",
        type=int,
        default=Config.loss_microbatch_size,
    )
    parser.add_argument(
        "--negative-filter-scope",
        choices=("full-training-history", "last-100"),
        default=Config.negative_filter_scope,
    )
    parser.add_argument(
        "--target-weighting",
        choices=("discovery-graded", "organic-strong", "uniform"),
        default=Config.target_weighting,
    )
    parser.add_argument(
        "--ordinary-target-weight",
        type=float,
        default=Config.ordinary_target_weight,
    )
    parser.add_argument(
        "--organic-strong-target-weight",
        type=float,
        default=Config.organic_strong_target_weight,
    )
    parser.add_argument(
        "--organic-like-target-weight",
        type=float,
        default=Config.organic_like_target_weight,
    )
    parser.add_argument(
        "--discovery-horizon-days",
        type=int,
        default=Config.discovery_horizon_days,
    )
    parser.add_argument(
        "--validation-fraction",
        type=float,
        default=Config.validation_fraction,
    )
    parser.add_argument(
        "--max-train-targets-per-user",
        type=int,
        default=Config.max_train_targets_per_user,
        help="retain this many recent pre-validation targets per user; 0 is uncapped",
    )
    parser.add_argument(
        "--max-validation-targets-per-user",
        type=int,
        default=Config.max_validation_targets_per_user,
        help="retain this many final validation targets per user; 0 is uncapped",
    )
    parser.add_argument(
        "--early-stopping-patience",
        type=int,
        default=Config.early_stopping_patience,
    )
    parser.add_argument(
        "--early-stopping-min-delta",
        type=float,
        default=Config.early_stopping_min_delta,
    )
    parser.add_argument("--checkpoint-dir", type=Path)
    parser.add_argument("--resume-checkpoint", type=Path)
    parser.add_argument("--seed", type=int, default=Config.seed)
    parser.add_argument("--ranking-batch-size", type=int, default=64)
    parser.add_argument("--prepare-only", action="store_true")
    args = parser.parse_args()

    if args.threads < 1 or args.bptt_steps < 2 or args.user_batch_size < 1:
        parser.error("threads, BPTT steps, and user batch size must be positive")
    if (
        args.epochs < 1
        or args.learning_rate <= 0
        or args.loss_microbatch_size < 1
        or args.early_stopping_patience < 1
        or args.early_stopping_min_delta < 0
        or args.ordinary_target_weight <= 0
        or args.organic_strong_target_weight <= 0
        or args.organic_like_target_weight <= 0
        or args.discovery_horizon_days < 1
        or args.max_train_targets_per_user < 0
        or args.max_validation_targets_per_user < 0
    ):
        parser.error("training counts, learning rate, and patience are invalid")
    if not 0.0 < args.validation_fraction < 1.0:
        parser.error("validation fraction must be strictly between zero and one")
    public = args.public_dir.resolve()
    if not (public / "data" / "candidate_catalog.parquet").is_file():
        parser.error(f"public task data not found under {public}")
    config = Config(
        bptt_steps=args.bptt_steps,
        user_batch_size=args.user_batch_size,
        epochs=args.epochs,
        learning_rate=args.learning_rate,
        loss_microbatch_size=args.loss_microbatch_size,
        negative_filter_scope=args.negative_filter_scope,
        target_weighting=args.target_weighting,
        ordinary_target_weight=args.ordinary_target_weight,
        organic_strong_target_weight=args.organic_strong_target_weight,
        organic_like_target_weight=args.organic_like_target_weight,
        discovery_horizon_days=args.discovery_horizon_days,
        validation_fraction=args.validation_fraction,
        max_train_targets_per_user=args.max_train_targets_per_user,
        max_validation_targets_per_user=args.max_validation_targets_per_user,
        early_stopping_patience=args.early_stopping_patience,
        early_stopping_min_delta=args.early_stopping_min_delta,
        seed=args.seed,
    )
71

replace train_current_model.py

+30:19
Tool callreplace/app/solution/train_current_model.py Returned

Tool call · Input

{
  "file_path": "/app/solution/train_current_model.py",
  "old_string": "    parser.add_argument(\"--checkpoint-dir\", type=Path)\n    parser.add_argument(\"--resume-checkpoint\", type=Path)\n    parser.add_argument(\"--seed\", type=int, default=Config.seed)\n    parser.add_argument(\"--ranking-batch-size\", type=int, default=64)\n    parser.add_argument(\"--prepare-only\", action=\"store_true\")\n    args = parser.parse_args()",
  "instruction": "Add CLI arguments and pass them to Config in main()",
  "new_string": "    parser.add_argument(\"--checkpoint-dir\", type=Path)\n    parser.add_argument(\"--resume-checkpoint\", type=Path)\n    parser.add_argument(\"--seed\", type=int, default=Config.seed)\n    parser.add_argument(\"--ranking-batch-size\", type=int, default=64)\n    parser.add_argument(\"--prepare-only\", action=\"store_true\")\n    parser.add_argument(\n        \"--loss-type\",\n        choices=(\"bce\", \"infonce\", \"bpr\"),\n        default=Config.loss_type,\n    )\n    parser.add_argument(\"--temperature\", type=float, default=Config.temperature)\n    parser.add_argument(\n        \"--uniform-negatives\", type=int, default=Config.uniform_negatives\n    )\n    parser.add_argument(\n        \"--inbatch-negatives\", type=int, default=Config.inbatch_negatives\n    )\n    parser.add_argument(\n        \"--inbatch-correction-power\",\n        type=float,\n        default=Config.inbatch_correction_power,\n    )\n    parser.add_argument(\"--inbatch-frequency-sample\", action=\"store_true\")\n    args = parser.parse_args()"
}

Tool response

Successfully modified file: /app/solution/train_current_model.py (1 replacements). Here is the updated code:
...
    parser.add_argument("--checkpoint-dir", type=Path)
    parser.add_argument("--resume-checkpoint", type=Path)
    parser.add_argument("--seed", type=int, default=Config.seed)
    parser.add_argument("--ranking-batch-size", type=int, default=64)
    parser.add_argument("--prepare-only", action="store_true")
    parser.add_argument(
        "--loss-type",
        choices=("bce", "infonce", "bpr"),
        default=Config.loss_type,
    )
    parser.add_argument("--temperature", type=float, default=Config.temperature)
    parser.add_argument(
        "--uniform-negatives", type=int, default=Config.uniform_negatives
    )
    parser.add_argument(
        "--inbatch-negatives", type=int, default=Config.inbatch_negatives
    )
    parser.add_argument(
        "--inbatch-correction-power",
        type=float,
        default=Config.inbatch_correction_power,
    )
    parser.add_argument("--inbatch-frequency-sample", action="store_true")
    args = parser.parse_args()

    if args.threads < 1 or args.bptt_steps < 2 or args.user_batch_size < 1:
        parser.error("threads, BPTT steps, and user batch size must be positive")
    if (
...
72

read_file train_current_model.py

+30:21
Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "file_path": "/app/solution/train_current_model.py",
  "start_line": 2055,
  "end_line": 2090
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 2055-2090 of 2207 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 2091.

--- FILE CONTENT (truncated) ---
        or args.early_stopping_patience < 1
        or args.early_stopping_min_delta < 0
        or args.ordinary_target_weight <= 0
        or args.organic_strong_target_weight <= 0
        or args.organic_like_target_weight <= 0
        or args.discovery_horizon_days < 1
        or args.max_train_targets_per_user < 0
        or args.max_validation_targets_per_user < 0
    ):
        parser.error("training counts, learning rate, and patience are invalid")
    if not 0.0 < args.validation_fraction < 1.0:
        parser.error("validation fraction must be strictly between zero and one")
    public = args.public_dir.resolve()
    if not (public / "data" / "candidate_catalog.parquet").is_file():
        parser.error(f"public task data not found under {public}")
    config = Config(
        bptt_steps=args.bptt_steps,
        user_batch_size=args.user_batch_size,
        epochs=args.epochs,
        learning_rate=args.learning_rate,
        loss_microbatch_size=args.loss_microbatch_size,
        negative_filter_scope=args.negative_filter_scope,
        target_weighting=args.target_weighting,
        ordinary_target_weight=args.ordinary_target_weight,
        organic_strong_target_weight=args.organic_strong_target_weight,
        organic_like_target_weight=args.organic_like_target_weight,
        discovery_horizon_days=args.discovery_horizon_days,
        validation_fraction=args.validation_fraction,
        max_train_targets_per_user=args.max_train_targets_per_user,
        max_validation_targets_per_user=args.max_validation_targets_per_user,
        early_stopping_patience=args.early_stopping_patience,
        early_stopping_min_delta=args.early_stopping_min_delta,
        seed=args.seed,
    )
    torch.set_num_threads(args.threads)
    torch.set_num_interop_threads(1)
73

replace train_current_model.py

+30:25
Tool callreplace/app/solution/train_current_model.py Returned

Tool call · Input

{
  "old_string": "        early_stopping_patience=args.early_stopping_patience,\n        early_stopping_min_delta=args.early_stopping_min_delta,\n        seed=args.seed,\n    )",
  "instruction": "Pass new CLI options to Config in main()",
  "file_path": "/app/solution/train_current_model.py",
  "new_string": "        early_stopping_patience=args.early_stopping_patience,\n        early_stopping_min_delta=args.early_stopping_min_delta,\n        seed=args.seed,\n        loss_type=args.loss_type,\n        temperature=args.temperature,\n        uniform_negatives=args.uniform_negatives,\n        inbatch_negatives=args.inbatch_negatives,\n        inbatch_correction_power=args.inbatch_correction_power,\n        inbatch_frequency_sample=args.inbatch_frequency_sample,\n    )"
}

Tool response

Successfully modified file: /app/solution/train_current_model.py (1 replacements). Here is the updated code:
...
        max_train_targets_per_user=args.max_train_targets_per_user,
        max_validation_targets_per_user=args.max_validation_targets_per_user,
        early_stopping_patience=args.early_stopping_patience,
        early_stopping_min_delta=args.early_stopping_min_delta,
        seed=args.seed,
        loss_type=args.loss_type,
        temperature=args.temperature,
        uniform_negatives=args.uniform_negatives,
        inbatch_negatives=args.inbatch_negatives,
        inbatch_correction_power=args.inbatch_correction_power,
        inbatch_frequency_sample=args.inbatch_frequency_sample,
    )
    torch.set_num_threads(args.threads)
    torch.set_num_interop_threads(1)
    seed_everything(config.seed)
    device = torch.device(args.device)
...
74

read_file train_current_model.py

+30:28
Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "start_line": 2150,
  "file_path": "/app/solution/train_current_model.py",
  "end_line": 2175
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 2150-2175 of 2213 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 2176.

--- FILE CONTENT (truncated) ---
    ranking, embedding_diagnostics = rank_candidates(
        model,
        prepared,
        eligibility,
        config,
        device,
        args.ranking_batch_size,
    )
    write_ranking(ranking, args.output.resolve())
    print(
        json.dumps(
            {
                "baseline": "yambda-windowed-sequence-two-tower-base",
                "stage": args.stage,
                "output": str(args.output.resolve()),
                "rows": len(ranking),
                "users": int(ranking.uid.nunique()),
                "runtime_seconds": round(time.monotonic() - started, 3),
                "public_inputs_only": True,
                "architecture": {
                    "family": "pure-windowed-sequence-two-tower",
                    "sequence_training": (
                        "every-adjacent-target-within-recent-chronological-window"
                    ),
                    "sequence_encoder": "one-layer-GRU-dense-timestep-loss",
                    "bptt_hidden_state": "carried-and-detached",
75

read_file train_current_model.py

+30:32
Recorded reasoning summary 34 words

Exploring Architecture Details

I'm currently examining the architecture block, specifically lines 2170-2190, to understand the scoring mechanism, objective function, and negative sampling strategy. This section is crucial for grasping the model's core learning process.

Tool callread_file/app/solution/train_current_model.py Returned

Tool call · Input

{
  "start_line": 2170,
  "file_path": "/app/solution/train_current_model.py",
  "end_line": 2200
}

Tool response


IMPORTANT: The file content has been truncated.
Status: Showing lines 2170-2200 of 2213 total lines.
Action: To read more of the file, you can use the 'start_line' and 'end_line' parameters in a subsequent 'read_file' call. For example, to read the next section of the file, use start_line: 2201.

--- FILE CONTENT (truncated) ---
                    "family": "pure-windowed-sequence-two-tower",
                    "sequence_training": (
                        "every-adjacent-target-within-recent-chronological-window"
                    ),
                    "sequence_encoder": "one-layer-GRU-dense-timestep-loss",
                    "bptt_hidden_state": "carried-and-detached",
                    "model_selection": "chronological-validation-BCE-early-stopping",
                    "loss_execution": "gradient-accumulated-microbatches",
                    "user_id_embedding": False,
                    "user_mlp": "582-512-256-192",
                    "item_mlp": "196-512-256-192",
                    "normalization": "none",
                    "score": "raw-dot-product",
                    "objective": "sample-weighted-BCE-at-every-timestep",
                    "negative_sampling": (
                        "24-uniform-plus-8-propensity-corrected-inbatch"
                    ),
                    "false_negative_filter": config.negative_filter_scope,
                    "target_weighting": config.target_weighting,
                },
                "config": asdict(config),
                "sequence_tokens": len(prepared.sequence_items),
                "all_next_item_targets": prepared.target_count,
                "selected_training_targets": int(
                    target_partition.training_counts.sum()
                ),
                "selected_validation_targets": int(
                    target_partition.validation_counts.sum()
                ),
                "discarded_old_targets": int(target_partition.window_starts.sum()),
                "training_history": training_history,
76

Train and evaluate InfoNCE with temp=0.1 on validation backtest

+30:41
Recorded reasoning summary 43 words

Testing Configurations

I'm currently exploring various configurations. My immediate focus is on verifying default execution and identifying any potential crashes. Following that, I plan to test specific loss types like BPR and InfoNCE, and will also investigate the optimal temperature setting for InfoNCE.

Tool callrun_shell_commandTrain and evaluate InfoNCE with temp=0.1 on validation backtest Returned

Tool call · Input

{
  "command": "python /app/solution/train_current_model.py \\\n  --stage validation \\\n  --public-dir /task \\\n  --prepared-cache /app/solution/prepared_val.npz \\\n  --target-weighting discovery-graded \\\n  --loss-type infonce \\\n  --temperature 0.1 \\\n  --output /app/solution/val_infonce_01.parquet\npython /task/evaluate_public.py /app/solution/val_infonce_01.parquet",
  "description": "Train and evaluate InfoNCE with temp=0.1 on validation backtest"
}

Tool response

<untrusted_context>
Output: loaded full-sequence cache: tokens=20,056,329 targets=20,047,194
chronological BCE window: train=1,052,953 validation=130,103 selected=1,183,056 discarded_old_targets=18,864,138 all=20,047,194
inbatch correction: min=0.250 mean_on_targets=1.001 max=4.000
loaded organic-like outcomes: rows=301,527 users=7,526
grade-3 first-encounter targets=46,417 horizon_days=7
target weighting=discovery-graded min=0.250 mean=0.310 max=3.000
full-history false-negative filter: users=9,135 unique_user_items=5,524,275 bytes=34,256,250
epoch=1/1 batches=250 targets=987,417 batch_bce=2.882234 running_bce=2.888013 elapsed=202.9s
epoch=1/1 train_loss=2.87533 validation_loss=2.66998 pair_accuracy=0.775 train_targets=1,052,953 validation_targets=130,103 train_seconds=216.3 validation_seconds=16.0
restored best validation-BCE checkpoint: epoch=1 loss=2.669981
ranked users=1,024/8,456
ranked users=2,048/8,456
ranked users=3,072/8,456
ranked users=4,096/8,456
ranked users=5,120/8,456
ranked users=6,144/8,456
ranked users=7,168/8,456
ranked users=8,192/8,456
ranked users=8,456/8,456
{
  "baseline": "yambda-windowed-sequence-two-tower-base",
  "stage": "validation",
  "output": "/app/solution/val_infonce_01.parquet",
  "rows": 845600,
  "users": 8456,
  "runtime_seconds": 327.088,
  "public_inputs_only": true,
  "architecture": {
    "family": "pure-windowed-sequence-two-tower",
    "sequence_training": "every-adjacent-target-within-recent-chronological-window",
    "sequence_encoder": "one-layer-GRU-dense-timestep-loss",
    "bptt_hidden_state": "carried-and-detached",
    "model_selection": "chronological-validation-BCE-early-stopping",
    "loss_execution": "gradient-accumulated-microbatches",
    "user_id_embedding": false,
    "user_mlp": "582-512-256-192",
    "item_mlp": "196-512-256-192",
    "normalization": "none",
    "score": "raw-dot-product",
    "objective": "sample-weighted-BCE-at-every-timestep",
    "negative_sampling": "24-uniform-plus-8-propensity-corrected-inbatch",
    "false_negative_filter": "full-training-history",
    "target_weighting": "discovery-graded"
  },
  "config": {
    "bptt_steps": 100,
    "user_batch_size": 64,
    "embedding_dim": 192,
    "hidden_dim": 192,
    "user_hidden_1": 512,
    "user_hidden_2": 256,
    "item_hidden_1": 512,
    "item_hidden_2": 256,
    "dropout": 0.05,
    "epochs": 1,
    "learning_rate": 0.001,
    "weight_decay": 1e-05,
    "gradient_clip": 2.0,
    "loss_microbatch_size": 65536,
    "uniform_negatives": 24,
    "inbatch_negatives": 8,
    "inbatch_correction_power": 0.5,
    "inbatch_correction_min": 0.25,
    "inbatch_correction_max": 4.0,
    "negative_filter_scope": "full-training-history",
    "target_weighting": "discovery-graded",
    "ordinary_target_weight": 0.25,
    "organic_strong_target_weight": 1.0,
    "organic_like_target_weight": 3.0,
    "discovery_horizon_days": 7,
    "validation_fraction": 0.1,
    "max_train_targets_per_user": 128,
    "max_validation_targets_per_user": 16,
    "early_stopping_patience": 1,
    "early_stopping_min_delta": 0.0001,
    "seed": 29,
    "loss_type": "infonce",
    "temperature": 0.1,
    "inbatch_frequency_sample": false
  },
  "sequence_tokens": 20056329,
  "all_next_item_targets": 20047194,
  "selected_training_targets": 1052953,
  "selected_validation_targets": 130103,
  "discarded_old_targets": 18864138,
  "training_history": [
    {
      "epoch": 1.0,
      "loss": 2.8753293548020498,
      "positive_logit": 0.01788053704554617,
      "negative_logit": -0.12286158901484713,
      "pair_accuracy": 0.7748257460209526,
      "targets": 1052953.0,
      "target_weight_sum": 348780.0,
      "batches": 266.0,
      "seconds": 216.32477699699984,
      "validation_loss": 2.669981013659102,
      "validation_targets": 130103.0,
      "validation_target_weight_sum": 42129.5,
      "validation_seconds": 16.029928746999758
    }
  ],
  "embedding_diagnostics": {
    "query_norm_mean": 0.6981537938117981,
    "query_norm_std": 0.19272516667842865,
    "item_norm_mean": 0.7907130122184753,
    "item_norm_std": 0.17432135343551636
  },
  "torch_version": "2.8.0+cpu",
  "device": "cpu"
}
{
  "model": "/app/solution/val_infonce_01.parquet",
  "scores": {
    "quality_ndcg@10": 0.018216,
    "quality_users": 4263
  }
}
Process Group PGID: 2000
</untrusted_context>
77

Remove temporary validation parquet

+36:23
Recorded reasoning summary 35 words

Observing Parameter Shift

I'm seeing a significant reduction in query_norm_mean and item_norm_mean, which dropped from 1.75 and 1.85 respectively. The positive_logit also decreased considerably from 0.77 to 0.0178, alongside a dip in quality_ndcg@10 to 0.018216.

Tool callrun_shell_commandRemove temporary validation parquet Returned

Tool call · Input

{
  "command": "rm -f /app/solution/val_infonce_01.parquet",
  "description": "Remove temporary validation parquet"
}

Tool response

<untrusted_context>
Output: (empty)
Process Group PGID: 2049
</untrusted_context>
78

Test inbatch_correction_power = 0.0 with discovery-graded weighting

+36:28
Recorded reasoning summary 31 words

Analyzing BCE Baseline

I'm currently dissecting the baseline BCE loss, specifically the 0.023522 achieved by discovery-graded. My focus is on investigating inbatch_correction_power's role, recalling its earlier tendency to downweight popular items.

Tool callrun_shell_commandTest inbatch_correction_power = 0.0 with discovery-graded weighting Returned

Tool call · Input

{
  "command": "python /app/solution/train_current_model.py \\\n  --stage validation \\\n  --public-dir /task \\\n  --prepared-cache /app/solution/prepared_val.npz \\\n  --target-weighting discovery-graded \\\n  --inbatch-correction-power 0.0 \\\n  --output /app/solution/val_corr_power_0.parquet\npython /task/evaluate_public.py /app/solution/val_corr_power_0.parquet",
  "description": "Test inbatch_correction_power = 0.0 with discovery-graded weighting"
}

Tool response

<untrusted_context>
Output: loaded full-sequence cache: tokens=20,056,329 targets=20,047,194
chronological BCE window: train=1,052,953 validation=130,103 selected=1,183,056 discarded_old_targets=18,864,138 all=20,047,194
inbatch correction: min=1.000 mean_on_targets=1.000 max=1.000
loaded organic-like outcomes: rows=301,527 users=7,526
grade-3 first-encounter targets=46,417 horizon_days=7
target weighting=discovery-graded min=0.250 mean=0.310 max=3.000
full-history false-negative filter: users=9,135 unique_user_items=5,524,275 bytes=34,256,250
epoch=1/1 batches=250 targets=987,417 batch_bce=0.563095 running_bce=0.563300 elapsed=202.2s
epoch=1/1 train_loss=0.56103 validation_loss=0.52015 pair_accuracy=0.763 train_targets=1,052,953 validation_targets=130,103 train_seconds=215.8 validation_seconds=16.1
restored best validation-BCE checkpoint: epoch=1 loss=0.520147
ranked users=1,024/8,456
ranked users=2,048/8,456
ranked users=3,072/8,456
ranked users=4,096/8,456
ranked users=5,120/8,456
ranked users=6,144/8,456
ranked users=7,168/8,456
ranked users=8,192/8,456
ranked users=8,456/8,456
{
  "baseline": "yambda-windowed-sequence-two-tower-base",
  "stage": "validation",
  "output": "/app/solution/val_corr_power_0.parquet",
  "rows": 845600,
  "users": 8456,
  "runtime_seconds": 328.131,
  "public_inputs_only": true,
  "architecture": {
    "family": "pure-windowed-sequence-two-tower",
    "sequence_training": "every-adjacent-target-within-recent-chronological-window",
    "sequence_encoder": "one-layer-GRU-dense-timestep-loss",
    "bptt_hidden_state": "carried-and-detached",
    "model_selection": "chronological-validation-BCE-early-stopping",
    "loss_execution": "gradient-accumulated-microbatches",
    "user_id_embedding": false,
    "user_mlp": "582-512-256-192",
    "item_mlp": "196-512-256-192",
    "normalization": "none",
    "score": "raw-dot-product",
    "objective": "sample-weighted-BCE-at-every-timestep",
    "negative_sampling": "24-uniform-plus-8-propensity-corrected-inbatch",
    "false_negative_filter": "full-training-history",
    "target_weighting": "discovery-graded"
  },
  "config": {
    "bptt_steps": 100,
    "user_batch_size": 64,
    "embedding_dim": 192,
    "hidden_dim": 192,
    "user_hidden_1": 512,
    "user_hidden_2": 256,
    "item_hidden_1": 512,
    "item_hidden_2": 256,
    "dropout": 0.05,
    "epochs": 1,
    "learning_rate": 0.001,
    "weight_decay": 1e-05,
    "gradient_clip": 2.0,
    "loss_microbatch_size": 65536,
    "uniform_negatives": 24,
    "inbatch_negatives": 8,
    "inbatch_correction_power": 0.0,
    "inbatch_correction_min": 0.25,
    "inbatch_correction_max": 4.0,
    "negative_filter_scope": "full-training-history",
    "target_weighting": "discovery-graded",
    "ordinary_target_weight": 0.25,
    "organic_strong_target_weight": 1.0,
    "organic_like_target_weight": 3.0,
    "discovery_horizon_days": 7,
    "validation_fraction": 0.1,
    "max_train_targets_per_user": 128,
    "max_validation_targets_per_user": 16,
    "early_stopping_patience": 1,
    "early_stopping_min_delta": 0.0001,
    "seed": 29,
    "loss_type": "bce",
    "temperature": 0.1,
    "inbatch_frequency_sample": false
  },
  "sequence_tokens": 20056329,
  "all_next_item_targets": 20047194,
  "selected_training_targets": 1052953,
  "selected_validation_targets": 130103,
  "discarded_old_targets": 18864138,
  "training_history": [
    {
      "epoch": 1.0,
      "loss": 0.5610289441109853,
      "positive_logit": 0.6264491075626895,
      "negative_logit": -0.6609028982207017,
      "pair_accuracy": 0.7632028388256645,
      "targets": 1052953.0,
      "target_weight_sum": 348780.0,
      "batches": 266.0,
      "seconds": 215.77226310900005,
      "validation_loss": 0.5201467735449403,
      "validation_targets": 130103.0,
      "validation_target_weight_sum": 42129.5,
      "validation_seconds": 16.066914179000378
    }
  ],
  "embedding_diagnostics": {
    "query_norm_mean": 1.8937625885009766,
    "query_norm_std": 0.849907636642456,
    "item_norm_mean": 1.7925585508346558,
    "item_norm_std": 0.7955368161201477
  },
  "torch_version": "2.8.0+cpu",
  "device": "cpu"
}
{
  "model": "/app/solution/val_corr_power_0.parquet",
  "scores": {
    "quality_ndcg@10": 0.015049,
    "quality_users": 4263
  }
}
Process Group PGID: 2052
</untrusted_context>
79

Remove temporary validation parquet

+42:29
Recorded reasoning summary 45 words

Analyzing Correction Impact

I'm investigating a significant NDCG drop to 0.0150 when inbatch_correction_power was set to 0.0, down from 0.0235 at 0.5. This suggests the correction mechanism, even at a low setting, is crucial. I'm now examining the build_item_correction function to understand the underlying calculation.

Tool callrun_shell_commandRemove temporary validation parquet Returned

Tool call · Input

{
  "description": "Remove temporary validation parquet",
  "command": "rm -f /app/solution/val_corr_power_0.parquet"
}

Tool response

<untrusted_context>
Output: (empty)
Process Group PGID: 2101
</untrusted_context>
80

Test inbatch_correction_power = 1.0 with discovery-graded weighting

+42:32
Tool callrun_shell_commandTest inbatch_correction_power = 1.0 with discovery-graded weighting Returned

Tool call · Input

{
  "command": "python /app/solution/train_current_model.py \\\n  --stage validation \\\n  --public-dir /task \\\n  --prepared-cache /app/solution/prepared_val.npz \\\n  --target-weighting discovery-graded \\\n  --inbatch-correction-power 1.0 \\\n  --output /app/solution/val_corr_power_1.parquet\npython /task/evaluate_public.py /app/solution/val_corr_power_1.parquet",
  "description": "Test inbatch_correction_power = 1.0 with discovery-graded weighting"
}

Tool response

<untrusted_context>
Output: loaded full-sequence cache: tokens=20,056,329 targets=20,047,194
chronological BCE window: train=1,052,953 validation=130,103 selected=1,183,056 discarded_old_targets=18,864,138 all=20,047,194
inbatch correction: min=0.250 mean_on_targets=0.971 max=4.000
loaded organic-like outcomes: rows=301,527 users=7,526
grade-3 first-encounter targets=46,417 horizon_days=7
target weighting=discovery-graded min=0.250 mean=0.310 max=3.000
full-history false-negative filter: users=9,135 unique_user_items=5,524,275 bytes=34,256,250
epoch=1/1 batches=250 targets=987,417 batch_bce=0.540607 running_bce=0.533212 elapsed=201.8s
epoch=1/1 train_loss=0.53122 validation_loss=0.49435 pair_accuracy=0.759 train_targets=1,052,953 validation_targets=130,103 train_seconds=215.4 validation_seconds=15.9
restored best validation-BCE checkpoint: epoch=1 loss=0.494347
ranked users=1,024/8,456
ranked users=2,048/8,456
ranked users=3,072/8,456
ranked users=4,096/8,456
ranked users=5,120/8,456
ranked users=6,144/8,456
ranked users=7,168/8,456
ranked users=8,192/8,456
ranked users=8,456/8,456
{
  "baseline": "yambda-windowed-sequence-two-tower-base",
  "stage": "validation",
  "output": "/app/solution/val_corr_power_1.parquet",
  "rows": 845600,
  "users": 8456,
  "runtime_seconds": 325.686,
  "public_inputs_only": true,
  "architecture": {
    "family": "pure-windowed-sequence-two-tower",
    "sequence_training": "every-adjacent-target-within-recent-chronological-window",
    "sequence_encoder": "one-layer-GRU-dense-timestep-loss",
    "bptt_hidden_state": "carried-and-detached",
    "model_selection": "chronological-validation-BCE-early-stopping",
    "loss_execution": "gradient-accumulated-microbatches",
    "user_id_embedding": false,
    "user_mlp": "582-512-256-192",
    "item_mlp": "196-512-256-192",
    "normalization": "none",
    "score": "raw-dot-product",
    "objective": "sample-weighted-BCE-at-every-timestep",
    "negative_sampling": "24-uniform-plus-8-propensity-corrected-inbatch",
    "false_negative_filter": "full-training-history",
    "target_weighting": "discovery-graded"
  },
  "config": {
    "bptt_steps": 100,
    "user_batch_size": 64,
    "embedding_dim": 192,
    "hidden_dim": 192,
    "user_hidden_1": 512,
    "user_hidden_2": 256,
    "item_hidden_1": 512,
    "item_hidden_2": 256,
    "dropout": 0.05,
    "epochs": 1,
    "learning_rate": 0.001,
    "weight_decay": 1e-05,
    "gradient_clip": 2.0,
    "loss_microbatch_size": 65536,
    "uniform_negatives": 24,
    "inbatch_negatives": 8,
    "inbatch_correction_power": 1.0,
    "inbatch_correction_min": 0.25,
    "inbatch_correction_max": 4.0,
    "negative_filter_scope": "full-training-history",
    "target_weighting": "discovery-graded",
    "ordinary_target_weight": 0.25,
    "organic_strong_target_weight": 1.0,
    "organic_like_target_weight": 3.0,
    "discovery_horizon_days": 7,
    "validation_fraction": 0.1,
    "max_train_targets_per_user": 128,
    "max_validation_targets_per_user": 16,
    "early_stopping_patience": 1,
    "early_stopping_min_delta": 0.0001,
    "seed": 29,
    "loss_type": "bce",
    "temperature": 0.1,
    "inbatch_frequency_sample": false
  },
  "sequence_tokens": 20056329,
  "all_next_item_targets": 20047194,
  "selected_training_targets": 1052953,
  "selected_validation_targets": 130103,
  "discarded_old_targets": 18864138,
  "training_history": [
    {
      "epoch": 1.0,
      "loss": 0.531223179207967,
      "positive_logit": 0.8379884010350294,
      "negative_logit": -0.6214525562306966,
      "pair_accuracy": 0.7585659390780025,
      "targets": 1052953.0,
      "target_weight_sum": 348780.0,
      "batches": 266.0,
      "seconds": 215.40360276399997,
      "validation_loss": 0.49434683065951257,
      "validation_targets": 130103.0,
      "validation_target_weight_sum": 42129.5,
      "validation_seconds": 15.922902670999974
    }
  ],
  "embedding_diagnostics": {
    "query_norm_mean": 1.4753897190093994,
    "query_norm_std": 0.6710734367370605,
    "item_norm_mean": 1.976240634918213,
    "item_norm_std": 0.8238486051559448
  },
  "torch_version": "2.8.0+cpu",
  "device": "cpu"
}
{
  "model": "/app/solution/val_corr_power_1.parquet",
  "scores": {
    "quality_ndcg@10": 0.023,
    "quality_users": 4263
  }
}
Process Group PGID: 2104
</untrusted_context>
81

Remove temporary validation parquet

+48:11
Tool callrun_shell_commandRemove temporary validation parquet Returned

Tool call · Input

{
  "command": "rm -f /app/solution/val_corr_power_1.parquet",
  "description": "Remove temporary validation parquet"
}

Tool response

<untrusted_context>
Output: (empty)
Process Group PGID: 2153
</untrusted_context>
82

Test uniform_negatives=16, inbatch_negatives=16

+48:14
Recorded reasoning summary 44 words

Adjusting Negative Sampling

I'm considering tweaking the balance between uniform and in-batch negative samples. My current hypothesis is to shift towards an equal distribution, specifically testing a 16:16 ratio from the current 24:8. I'll proceed with this exploration to see how it impacts performance.

Tool callrun_shell_commandTest uniform_negatives=16, inbatch_negatives=16 Returned

Tool call · Input

{
  "description": "Test uniform_negatives=16, inbatch_negatives=16",
  "command": "python /app/solution/train_current_model.py \\\n  --stage validation \\\n  --public-dir /task \\\n  --prepared-cache /app/solution/prepared_val.npz \\\n  --target-weighting discovery-graded \\\n  --uniform-negatives 16 \\\n  --inbatch-negatives 16 \\\n  --output /app/solution/val_u16_i16.parquet\npython /task/evaluate_public.py /app/solution/val_u16_i16.parquet"
}

Tool response

<untrusted_context>
Output: loaded full-sequence cache: tokens=20,056,329 targets=20,047,194
chronological BCE window: train=1,052,953 validation=130,103 selected=1,183,056 discarded_old_targets=18,864,138 all=20,047,194
inbatch correction: min=0.250 mean_on_targets=1.001 max=4.000
loaded organic-like outcomes: rows=301,527 users=7,526
grade-3 first-encounter targets=46,417 horizon_days=7
target weighting=discovery-graded min=0.250 mean=0.310 max=3.000
full-history false-negative filter: users=9,135 unique_user_items=5,524,275 bytes=34,256,250
epoch=1/1 batches=250 targets=987,417 batch_bce=0.556066 running_bce=0.556343 elapsed=194.5s
epoch=1/1 train_loss=0.55431 validation_loss=0.52006 pair_accuracy=0.726 train_targets=1,052,953 validation_targets=130,103 train_seconds=207.5 validation_seconds=14.6
restored best validation-BCE checkpoint: epoch=1 loss=0.520058
ranked users=1,024/8,456
ranked users=2,048/8,456
ranked users=3,072/8,456
ranked users=4,096/8,456
ranked users=5,120/8,456
ranked users=6,144/8,456
ranked users=7,168/8,456
ranked users=8,192/8,456
ranked users=8,456/8,456
{
  "baseline": "yambda-windowed-sequence-two-tower-base",
  "stage": "validation",
  "output": "/app/solution/val_u16_i16.parquet",
  "rows": 845600,
  "users": 8456,
  "runtime_seconds": 317.967,
  "public_inputs_only": true,
  "architecture": {
    "family": "pure-windowed-sequence-two-tower",
    "sequence_training": "every-adjacent-target-within-recent-chronological-window",
    "sequence_encoder": "one-layer-GRU-dense-timestep-loss",
    "bptt_hidden_state": "carried-and-detached",
    "model_selection": "chronological-validation-BCE-early-stopping",
    "loss_execution": "gradient-accumulated-microbatches",
    "user_id_embedding": false,
    "user_mlp": "582-512-256-192",
    "item_mlp": "196-512-256-192",
    "normalization": "none",
    "score": "raw-dot-product",
    "objective": "sample-weighted-BCE-at-every-timestep",
    "negative_sampling": "24-uniform-plus-8-propensity-corrected-inbatch",
    "false_negative_filter": "full-training-history",
    "target_weighting": "discovery-graded"
  },
  "config": {
    "bptt_steps": 100,
    "user_batch_size": 64,
    "embedding_dim": 192,
    "hidden_dim": 192,
    "user_hidden_1": 512,
    "user_hidden_2": 256,
    "item_hidden_1": 512,
    "item_hidden_2": 256,
    "dropout": 0.05,
    "epochs": 1,
    "learning_rate": 0.001,
    "weight_decay": 1e-05,
    "gradient_clip": 2.0,
    "loss_microbatch_size": 65536,
    "uniform_negatives": 16,
    "inbatch_negatives": 16,
    "inbatch_correction_power": 0.5,
    "inbatch_correction_min": 0.25,
    "inbatch_correction_max": 4.0,
    "negative_filter_scope": "full-training-history",
    "target_weighting": "discovery-graded",
    "ordinary_target_weight": 0.25,
    "organic_strong_target_weight": 1.0,
    "organic_like_target_weight": 3.0,
    "discovery_horizon_days": 7,
    "validation_fraction": 0.1,
    "max_train_targets_per_user": 128,
    "max_validation_targets_per_user": 16,
    "early_stopping_patience": 1,
    "early_stopping_min_delta": 0.0001,
    "seed": 29,
    "loss_type": "bce",
    "temperature": 0.1,
    "inbatch_frequency_sample": false
  },
  "sequence_tokens": 20056329,
  "all_next_item_targets": 20047194,
  "selected_training_targets": 1052953,
  "selected_validation_targets": 130103,
  "discarded_old_targets": 18864138,
  "training_history": [
    {
      "epoch": 1.0,
      "loss": 0.5543083903753837,
      "positive_logit": 0.6960524614353784,
      "negative_logit": -0.5012892156770395,
      "pair_accuracy": 0.7255772871628648,
      "targets": 1052953.0,
      "target_weight_sum": 348780.0,
      "batches": 266.0,
      "seconds": 207.45100623500002,
      "validation_loss": 0.5200578083106654,
      "validation_targets": 130103.0,
      "validation_target_weight_sum": 42129.5,
      "validation_seconds": 14.572256708000168
    }
  ],
  "embedding_diagnostics": {
    "query_norm_mean": 1.7176122665405273,
    "query_norm_std": 0.8431686758995056,
    "item_norm_mean": 1.8370518684387207,
    "item_norm_std": 0.7449614405632019
  },
  "torch_version": "2.8.0+cpu",
  "device": "cpu"
}
{
  "model": "/app/solution/val_u16_i16.parquet",
  "scores": {
    "quality_ndcg@10": 0.020984,
    "quality_users": 4263
  }
}
Process Group PGID: 2156
</untrusted_context>
83

Remove temporary validation parquet

+53:45
Tool callrun_shell_commandRemove temporary validation parquet Returned

Tool call · Input

{
  "description": "Remove temporary validation parquet",
  "command": "rm -f /app/solution/val_u16_i16.parquet"
}

Tool response

<untrusted_context>
Output: (empty)
Process Group PGID: 2207
</untrusted_context>
84

Test uniform_negatives=32, inbatch_negatives=0

+53:53
Recorded reasoning summary 32 words

Investigating In-Batch Negative Impact

I'm currently probing a peculiar performance dip. Introducing more in-batch negatives unexpectedly lowered pair accuracy and NDCG scores. I'm analyzing the underlying mechanisms to understand this counter-intuitive effect.

Recorded reasoning summary 46 words

Examining Candidate Sets

I'm diving into how validation and test candidates are defined, noting they exclude training and validation encounters respectively. The relevance criteria for these candidates, based on user organic engagement, seems key. I'm also scrutinizing the high popularity of relevant items in our dataset.

Recorded reasoning summary 37 words

Exploring Negative Sampling Strategy

I'm re-evaluating our negative sampling. The full-training-history scope seems correct, but I'm questioning the impact of uniform negatives versus in-batch ones, especially their interaction and relative quantities, to explain the recent performance anomalies.

Tool callrun_shell_commandTest uniform_negatives=32, inbatch_negatives=0 Returned

Tool call · Input

{
  "command": "python /app/solution/train_current_model.py \\\n  --stage validation \\\n  --public-dir /task \\\n  --prepared-cache /app/solution/prepared_val.npz \\\n  --target-weighting discovery-graded \\\n  --uniform-negatives 32 \\\n  --inbatch-negatives 0 \\\n  --output /app/solution/val_u32_i0.parquet\npython /task/evaluate_public.py /app/solution/val_u32_i0.parquet",
  "description": "Test uniform_negatives=32, inbatch_negatives=0"
}

Tool response

<untrusted_context>
Output: loaded full-sequence cache: tokens=20,056,329 targets=20,047,194
chronological BCE window: train=1,052,953 validation=130,103 selected=1,183,056 discarded_old_targets=18,864,138 all=20,047,194
inbatch correction: min=0.250 mean_on_targets=1.001 max=4.000
loaded organic-like outcomes: rows=301,527 users=7,526
grade-3 first-encounter targets=46,417 horizon_days=7
target weighting=discovery-graded min=0.250 mean=0.310 max=3.000
full-history false-negative filter: users=9,135 unique_user_items=5,524,275 bytes=34,256,250
epoch=1/1 batches=250 targets=987,417 batch_bce=0.542264 running_bce=0.527347 elapsed=186.7s
epoch=1/1 train_loss=0.52544 validation_loss=0.48448 pair_accuracy=0.798 train_targets=1,052,953 validation_targets=130,103 train_seconds=199.1 validation_seconds=15.3
restored best validation-BCE checkpoint: epoch=1 loss=0.484480
ranked users=1,024/8,456
ranked users=2,048/8,456
ranked users=3,072/8,456
ranked users=4,096/8,456
ranked users=5,120/8,456
ranked users=6,144/8,456
ranked users=7,168/8,456
ranked users=8,192/8,456
ranked users=8,456/8,456
{
  "baseline": "yambda-windowed-sequence-two-tower-base",
  "stage": "validation",
  "output": "/app/solution/val_u32_i0.parquet",
  "rows": 845600,
  "users": 8456,
  "runtime_seconds": 310.452,
  "public_inputs_only": true,
  "architecture": {
    "family": "pure-windowed-sequence-two-tower",
    "sequence_training": "every-adjacent-target-within-recent-chronological-window",
    "sequence_encoder": "one-layer-GRU-dense-timestep-loss",
    "bptt_hidden_state": "carried-and-detached",
    "model_selection": "chronological-validation-BCE-early-stopping",
    "loss_execution": "gradient-accumulated-microbatches",
    "user_id_embedding": false,
    "user_mlp": "582-512-256-192",
    "item_mlp": "196-512-256-192",
    "normalization": "none",
    "score": "raw-dot-product",
    "objective": "sample-weighted-BCE-at-every-timestep",
    "negative_sampling": "24-uniform-plus-8-propensity-corrected-inbatch",
    "false_negative_filter": "full-training-history",
    "target_weighting": "discovery-graded"
  },
  "config": {
    "bptt_steps": 100,
    "user_batch_size": 64,
    "embedding_dim": 192,
    "hidden_dim": 192,
    "user_hidden_1": 512,
    "user_hidden_2": 256,
    "item_hidden_1": 512,
    "item_hidden_2": 256,
    "dropout": 0.05,
    "epochs": 1,
    "learning_rate": 0.001,
    "weight_decay": 1e-05,
    "gradient_clip": 2.0,
    "loss_microbatch_size": 65536,
    "uniform_negatives": 32,
    "inbatch_negatives": 0,
    "inbatch_correction_power": 0.5,
    "inbatch_correction_min": 0.25,
    "inbatch_correction_max": 4.0,
    "negative_filter_scope": "full-training-history",
    "target_weighting": "discovery-graded",
    "ordinary_target_weight": 0.25,
    "organic_strong_target_weight": 1.0,
    "organic_like_target_weight": 3.0,
    "discovery_horizon_days": 7,
    "validation_fraction": 0.1,
    "max_train_targets_per_user": 128,
    "max_validation_targets_per_user": 16,
    "early_stopping_patience": 1,
    "early_stopping_min_delta": 0.0001,
    "seed": 29,
    "loss_type": "bce",
    "temperature": 0.1,
    "inbatch_frequency_sample": false
  },
  "sequence_tokens": 20056329,
  "all_next_item_targets": 20047194,
  "selected_training_targets": 1052953,
  "selected_validation_targets": 130103,
  "discarded_old_targets": 18864138,
  "training_history": [
    {
      "epoch": 1.0,
      "loss": 0.5254377354844952,
      "positive_logit": 0.9194933287193273,
      "negative_logit": -0.8096884086535646,
      "pair_accuracy": 0.7977172592223964,
      "targets": 1052953.0,
      "target_weight_sum": 348780.0,
      "batches": 266.0,
      "seconds": 199.0963418270003,
      "validation_loss": 0.4844796381698273,
      "validation_targets": 130103.0,
      "validation_target_weight_sum": 42129.5,
      "validation_seconds": 15.340325407999899
    }
  ],
  "embedding_diagnostics": {
    "query_norm_mean": 1.4759684801101685,
    "query_norm_std": 0.6978867053985596,
    "item_norm_mean": 1.9009125232696533,
    "item_norm_std": 0.8285666108131409
  },
  "torch_version": "2.8.0+cpu",
  "device": "cpu"
}
{
  "model": "/app/solution/val_u32_i0.parquet",
  "scores": {
    "quality_ndcg@10": 0.022328,
    "quality_users": 4263
  }
}
Process Group PGID: 2210
</untrusted_context>
85

Remove temporary validation parquet

+59:18
Recorded reasoning summary 43 words

Exploring Negative Sampling Strategies

I'm evaluating the impact of negative sampling. While increasing uniform negatives boosted pair accuracy significantly, it appears to have slightly reduced NDCG. This suggests a need for a balanced approach, potentially incorporating some in-batch negatives for optimal retrieval performance.

Tool callrun_shell_commandRemove temporary validation parquet Returned

Tool call · Input

{
  "command": "rm -f /app/solution/val_u32_i0.parquet",
  "description": "Remove temporary validation parquet"
}

Tool response

<untrusted_context>
Output: (empty)
Process Group PGID: 2259
</untrusted_context>
86

Final response

+59:26
Recorded reasoning summary 45 words

Exploring Negative Sample Sizes

I'm currently investigating the impact of a higher total number of negative samples, specifically exploring a configuration with 48 uniform and 16 in-batch negatives (totaling 64). My next step is to assess how runtime scales under these increased negative sampling conditions.

Recorded session usage
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About this recording

The full recorded conversation: task prompt, agent messages, thinking text when available, tool inputs and outputs, and harness context. Empty thinking entries are labeled unavailable, not reconstructed from tool calls. Disclosures change the view; they do not shorten the content. Any truncation already present in tool output is preserved.

Steps follow the recorded model messages and reasoning events. Tool results appear with their originating call. Elapsed time starts with the first recorded event and excludes verification.

Attempt
gemini-3-8-flash-high-case1-r03-b9049e57
Recorded model
gemini-3.8-flash
Harness version
0.61.0
Session
8842e4c8-6a15-4061-85ca-59a129e959a4
Source SHA-256
7249d1eb96bcecde92a80508cc6880db13f3f4a9f8689574d36a85e7b9e56889

Session bookkeeping and encrypted reasoning or signatures are excluded from the reading export. The harness’s system prompt is not present in this session archive.