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Basic recommender opus-high-02

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

Thinking text is unavailable for this run. The archive contains 16 empty thinking entries; tool calls are shown separately.

Agent
opus-5.0 · Claude Code · high effort
Recorded conversation
13:35 · 27 steps
Private reward
0.020738 · Failed
Attempt cost
$1.65
  • Thinking
  • Model text
  • Tool call
  • Tool response
01

Task instructions

+00:00
Task instructions

Build a music-discovery ranker

Build the strongest ranking model you can for the "Made for You" shelf of a music streaming service. Per-user candidate eligibility, cutoff-specific explicit preference state, and a temporal backtest are provided. Candidate eligibility is platform-owned; all modeling within that candidate boundary is in scope.

Data

All inputs are under /task/data/. Training data ends at timestamp 24786800. A 30-minute gap precedes a seven-day public validation window. The hidden test is the following seven-day window after another 30-minute gap.

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. Build and tune a validation ranker using only train_* as history and val_* as subsequent outcomes.
  2. After selecting the approach, 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").

The exact available Python distribution inventory is listed in /task/requirements.txt. 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 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.

Public tools

/task/evaluate_public.py scores a validation-stage ranking against the public window. Pass the path to a ranking with the same schema as the final deliverable:

python /task/evaluate_public.py solution/validation.parquet

Stage-independent evaluation helpers are available in /task/ranking_evaluation.py. The builder installs the same checked-in module in the public agent image and private verifier image so scoring mechanics cannot drift. The public copy contains no hidden labels, evaluator-owned data paths, or pass thresholds.

The public evaluator uses validation_eligible_candidates.npz; it is not a validator for the final artifact. No model, fitted representation, example submission, or modeling architecture is supplied. Build and tune the best model you can, then refit the selected approach as described above.

Deliverable

Write /app/solution/submission.parquet or /app/solution/submission.csv, with exactly 100 rows for every target user and columns uid, item_id, rank. Ranks must be the integers 1-100 with no ties or duplicate items. Every submitted item must be present in that user's test_eligible_candidates.npz candidate set.

Leave the code that builds the artifact and a concise /app/solution/README.md in /app/solution/. Keep the best valid submission saved throughout the attempt so it survives the deadline.

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.
  • You have up to 30 minutes. Improve the model as much as possible within that limit. Structural validity alone is not sufficient; the final submission is also evaluated for ranking quality.
Harness context deferred tools delta
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Harness context agent listing delta
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    "- Explore: Read-only search agent for broad fan-out searches — when answering means sweeping many files, directories, or naming conventions and you only need the conclusion, not the file dumps. It reads excerpts rather than whole files, so it locates code; it doesn't review or audit it. Specify search breadth: \"medium\" for moderate exploration, \"very thorough\" for multiple locations and naming conventions. (Tools: All tools except Agent, Artifact, ExitPlanMode, Edit, Write, NotebookEdit)",
    "- general-purpose: General-purpose agent for researching complex questions, searching for code, and executing multi-step tasks. When you are searching for a keyword or file and are not confident that you will find the right match in the first few tries use this agent to perform the search for you. (Tools: *)",
    "- Plan: Software architect agent for designing implementation plans. Use this when you need to plan the implementation strategy for a task. Returns step-by-step plans, identifies critical files, and considers architectural trade-offs. (Tools: All tools except Agent, Artifact, ExitPlanMode, Edit, Write, NotebookEdit)",
    "- statusline-setup: Use this agent to configure the user's Claude Code status line setting. (Tools: Read, Edit)"
  ],
  "removedTypes": [],
  "isInitial": true,
  "showConcurrencyNote": false
}
Harness context skill listing
{
  "type": "skill_listing",
  "content": "- dataviz: Use this skill whenever you are about to create ANY chart, graph, plot, dashboard, or data visualization, in ANY output medium — an HTML or React artifact, inline SVG, plotting code in any library (matplotlib, plotly, d3, Recharts, …), an image/PNG you will render and upload, or a chart shared into Slack. Read it BEFORE writing the first line of chart code, choosing chart colors, building a stat tile / meter / KPI row, or laying out a dashboard. When the destination is a first-party document connector (host-designated, never self-described) that renders live charts, hand it the rows (inline, or as an uploaded data file the chart cites) rather than a rendered PNG/SVG — a picture of a chart loses hover, data inspection and per-value comments. Produces visualizations that read as one system — elegant, accessible, consistent in light and dark — using a brand-neutral placeholder palette you swap for your own. Teaches a design-system-agnostic method: a form heuristic, a color formula with a runnable validator, mark specs, and interaction rules. A validated default palette is documented in `references/palette.md` — swap that file's values for your brand's. Triggers on: \"chart\", \"graph\", \"plot\", \"data viz\", \"visualization\", \"dashboard\", \"analytics\", \"visualize data\", \"categorical colors\", \"sequential / diverging palette\", \"stat tile\", \"sparkline\", \"heatmap\", \"legend\", \"axis\", \"tooltip\", \"chart colors\", \"color by series\".\n- update-config: Use this skill to configure the Claude Code harness via settings.json. Automated behaviors (\"from now on when X\", \"each time X\", \"whenever X\", \"before/after X\") require hooks configured in settings.json - the harness executes these, not Claude, so memory/preferences cannot fulfill them. 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Examples: \"rebind ctrl+s\", \"add a chord shortcut\", \"change the submit key\", \"customize keybindings\".\n- code-review: Review the current diff, or a PR number/branch/path target, for correctness bugs and reuse/simplification/efficiency cleanups at the given effort level (low/medium: fewer, high-confidence findings; high→max: broader coverage, may include uncertain findings); with no level given, it reuses the level you typed last. Pass --comment to post findings as inline PR comments, or --fix to apply the findings to the working tree after the review.\n- simplify: Review the changed code for reuse, simplification, efficiency, and altitude cleanups, then apply the fixes. Quality only — it does not hunt for bugs; use /code-review for that.\n- fewer-permission-prompts: Scan your transcripts for common read-only Bash and MCP tool calls, then add a prioritized allowlist to project .claude/settings.json to reduce permission prompts.\n- loop: Run a prompt or slash command on a recurring interval (e.g. /loop 5m /foo). Omit the interval to let the model self-pace. - When the user wants to set up a recurring task, poll for status, or run something repeatedly on an interval (e.g. \"check the deploy every 5 minutes\", \"keep running /babysit-prs\"). Do NOT invoke for one-off tasks.\n- schedule: Create, update, list, or run scheduled cloud agents (routines) that execute on a cron schedule. - When the user wants to schedule a recurring cloud agent, set up automated tasks, create a cron job for Claude Code, or manage their scheduled agents/routines. Also use when the user wants a one-time scheduled run (\"run this once at 3pm\", \"remind me to check X tomorrow\").\n- claude-api: Reference for the Claude API / Anthropic SDK — model ids, pricing, params, streaming, tool use, MCP, agents, caching, token counting, model migration.\nTRIGGER — read BEFORE opening the target file; don't skip because it \"looks like a one-liner\" — whenever: the prompt names Claude/Anthropic in any form (Claude, Anthropic, Fable, Opus, Sonnet, Haiku, `anthropic`, `@anthropic-ai`, `claude-*`, `us.anthropic.*`, `[1m]`); the user asks about an LLM (pricing/model choice/limits/caching) — never answer from memory; OR the task is LLM-shaped with provider unstated (agent/MCP/tool-definition/multi-agent/RAG/LLM-judge/computer-use; generate/summarize/extract/classify/rewrite/converse over NL; debugging refusals/cutoffs/streaming/tool-calls/tokens).\nSKIP only when another provider is being worked on (overrides all triggers): OpenAI/GPT/Gemini/Llama/Mistral/Cohere/Ollama named in the query; OR `grep -rE 'openai|langchain_openai|google.generativeai|genai|mistralai|cohere|ollama'` over the project hits (run this grep FIRST if no provider named — don't Read the file).\n- workflow-authoring: Reference for writing a Workflow tool script (script API and gotchas, resume, quality patterns, worked examples). Load before authoring a script for a workflow the user already opted into; it does not itself authorize running one.\n- run: Launch and drive this project's app to see a change working. Use when asked to run, start, or screenshot the app, or to confirm a change works in the real app (not just tests). First looks for a project skill that already covers launching the app; otherwise falls back to built-in patterns per project type (CLI, server, TUI, Electron, browser-driven, library).\n- init: Initialize a new CLAUDE.md file with codebase documentation\n- security-review: Complete a security review of the pending changes on the current branch",
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Harness context total tokens reminder
{
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02

Explore task data directory

+00:01

Model text

I'll start by exploring the data and environment.

Tool callBashExplore task data directory Returned

Tool call · Input

ls -la /task/ /task/data/ && cat /task/requirements.txt | head -50 && nproc && free -g

Tool response

/task/:
total 36
dr-xr-xr-x 1 root root 4096 Sep 24 07:41 .
drwxr-xr-x 1 root root 4096 Sep 24 07:43 ..
dr-xr-xr-x 1 root root 4096 Sep 24 07:38 data
-r--r--r-- 1 root root 5774 Sep 24 07:37 evaluate_public.py
-r--r--r-- 1 root root 8265 Sep 24 07:37 ranking_evaluation.py
-r--r--r-- 1 root root 1278 Sep 24 07:37 requirements.txt

/task/data/:
total 347392
dr-xr-xr-x 1 root root      4096 Sep 24 07:38 .
dr-xr-xr-x 1 root root      4096 Sep 24 07:41 ..
-r--r--r-- 1 root root    349352 Sep 24 07:37 candidate_catalog.parquet
-r--r--r-- 1 root root     84127 Sep 24 07:37 target_users.parquet
-r--r--r-- 1 root root   7736341 Sep 24 07:37 test_eligible_candidates.npz
-r--r--r-- 1 root root   1092329 Sep 24 07:38 test_preference_state.parquet
-r--r--r-- 1 root root    857213 Sep 24 07:37 train_dislikes.parquet
-r--r--r-- 1 root root   5374652 Sep 24 07:37 train_likes.parquet
-r--r--r-- 1 root root 319183255 Sep 24 07:37 train_listens.parquet
-r--r--r-- 1 root root    155988 Sep 24 07:37 train_undislikes.parquet
-r--r--r-- 1 root root   1855885 Sep 24 07:37 train_unlikes.parquet
-r--r--r-- 1 root root     36571 Sep 24 07:37 val_dislikes.parquet
-r--r--r-- 1 root root    298484 Sep 24 07:37 val_likes.parquet
-r--r--r-- 1 root root   9947609 Sep 24 07:37 val_listens.parquet
-r--r--r-- 1 root root      7845 Sep 24 07:37 val_undislikes.parquet
-r--r--r-- 1 root root     72536 Sep 24 07:37 val_unlikes.parquet
-r--r--r-- 1 root root   7573821 Sep 24 07:37 validation_eligible_candidates.npz
-r--r--r-- 1 root root   1061761 Sep 24 07:38 validation_preference_state.parquet
# Exact third-party distribution inventory for yambda-discovery-ranking-v01.
#
# This is an input to `uv pip sync`, not a list of minimum requirements. A
# conforming task environment contains exactly these third-party Python
# distributions and no others. The same inventory is used for source preparation,
# task building, reference scoring, judging, and solver attempts. Python itself
# is pinned by task.toml and both Harbor image Dockerfiles.
attrs==26.1.0
bleach==6.4.0
certifi==2026.7.22
chardet==7.6.0
charset-normalizer==3.5.1
fastjsonschema==2.22.2
idna==3.18
joblib==1.5.3
jsonschema==4.26.0
jsonschema-specifications==2025.9.1
jupyter-core==5.9.1
jupytext==1.19.5
kaggle==2.2.4
kagglesdk==0.1.37
markdown-it-py==4.2.0
mdit-py-plugins==0.6.1
mdurl==0.1.2
nbformat==5.11.1
numpy==2.2.6
packaging==26.3
pandas==2.3.3
pillow==12.3.0
pip==26.0.1
platformdirs==4.11.3
protobuf==7.35.1
pyarrow==18.1.0
python-dateutil==2.9.0.post0
python-dotenv==1.2.3
python-slugify==8.0.4
pytz==2026.3.post1
PyYAML==6.0.3
referencing==0.37.0
reportlab==4.2.5
requests==2.34.2
rpds-py==2026.6.3
scikit-learn==1.7.2
scipy==1.15.3
six==1.17.0
text-unidecode==1.3
threadpoolctl==3.6.0
tqdm==4.70.0
traitlets==5.16.1
typing-extensions==4.16.0
8
               total        used        free      shared  buff/cache   available
Mem:              15           1           4           0           9          14
Swap:              0           0           0
Tool callBashRead evaluation code Returned

Tool call · Input

cat /task/ranking_evaluation.py; echo ---- ; cat /task/evaluate_public.py

Tool response

"""Shared public primitives for Yambda discovery-ranking evaluation.

Both the solver-visible validation evaluator and the private submission judge
import this module from the generated task's ``public`` directory. It owns the
stage-independent contract: reading a ranking, validating its shape, converting
it to per-user rank order, looking up packed candidate eligibility, and
computing graded NDCG@10.

The module deliberately contains no event-derived labels, private artifact
paths, or pass thresholds. Each evaluator supplies its own relevance data and
per-cutoff eligibility checks around these common operations.
"""
from __future__ import annotations

from pathlib import Path

import numpy as np
import pandas as pd


__all__ = [
    "CandidateSet",
    "QUALITY_K",
    "RankingValidationError",
    "REQUIRED_COLUMNS",
    "TOP_N",
    "ndcg_at_k",
    "ranked_items",
    "read_ranking",
    "score_rankings",
    "validate_ranking",
]

TOP_N = 100
QUALITY_K = 10
REQUIRED_COLUMNS = ("uid", "item_id", "rank")


class RankingValidationError(ValueError):
    """Report a ranking-schema or structural-contract violation."""


class CandidateSet:
    """Provide membership lookups over one packed candidate-set archive.

    The archive contains aligned ``uids``, ``item_ids``, and
    ``packed_eligible`` arrays. Candidate column ``c`` is represented by bit
    ``c % 8`` of byte ``c // 8`` using little-endian bit order. Arrays are
    copied into memory so they remain valid after the archive is closed.
    """

    def __init__(self, path: Path):
        """Load an eligibility archive and build ID-to-position indexes.

        Args:
            path: Path to a ``.npz`` archive with the candidate-set schema.
        """
        with np.load(path, allow_pickle=False) as artifact:
            self.uids = artifact["uids"].astype(np.int64, copy=True)
            self.item_ids = artifact["item_ids"].astype(np.int64, copy=True)
            self.packed = artifact["packed_eligible"].astype(np.uint8, copy=True)
        self.uid_row = {int(uid): row for row, uid in enumerate(self.uids)}
        self.item_column = {
            int(item): column for column, item in enumerate(self.item_ids)
        }

    def is_eligible(self, uid: int, item_id: int) -> bool:
        """Return whether ``item_id`` is eligible for ``uid``.

        IDs absent from the target-user or candidate-item arrays are treated as
        ineligible rather than raising an exception.

        Args:
            uid: Target user ID to query.
            item_id: Candidate item ID to query.

        Returns:
            ``True`` only when the corresponding packed eligibility bit is set.
        """
        row = self.uid_row.get(int(uid))
        column = self.item_column.get(int(item_id))
        if row is None or column is None:
            return False
        byte, bit = divmod(column, 8)
        return bool((int(self.packed[row, byte]) >> bit) & 1)


def read_ranking(path: Path) -> pd.DataFrame:
    """Read a parquet or CSV ranking into a pandas frame.

    Args:
        path: Input path. A ``.parquet`` suffix selects parquet; every other
            suffix is interpreted as CSV.

    Returns:
        The ranking frame as loaded by pandas.
    """
    return pd.read_parquet(path) if path.suffix == ".parquet" else pd.read_csv(path)


def validate_ranking(
    frame: pd.DataFrame,
    targets: set[int],
) -> pd.DataFrame:
    """Normalize and validate the stage-independent ranking contract.

    Required values must be finite integers. The user set must exactly match
    ``targets``; every user must have 100 rows, distinct items, and each rank
    from 1 through 100 exactly once. Cutoff-specific candidate eligibility is
    intentionally left to the calling evaluator.

    Args:
        frame: Raw ranking frame. Extra columns are discarded from an internal
            copy; the caller's frame is not modified.
        targets: Exact set of target user IDs the ranking must cover.

    Returns:
        A normalized frame containing only the required ``int64`` columns.

    Raises:
        RankingValidationError: If the ranking violates the shared contract.
    """
    required = list(REQUIRED_COLUMNS)
    if not all(column in frame for column in required):
        raise RankingValidationError(f"submission requires columns {required}")

    normalized = frame[required].copy()
    for column in required:
        numeric = pd.to_numeric(normalized[column], errors="coerce")
        values = numeric.to_numpy(dtype=float)
        if numeric.isna().any() or not np.isfinite(values).all():
            raise RankingValidationError(
                f"submission {column} must be finite numeric values"
            )
        if not np.equal(numeric, np.floor(numeric)).all():
            raise RankingValidationError(
                f"submission {column} must contain integers"
            )
        normalized[column] = numeric.astype(np.int64)

    submitted_users = set(map(int, normalized.uid.unique()))
    if submitted_users != targets:
        raise RankingValidationError(
            f"submission user set mismatch: missing={len(targets - submitted_users)} "
            f"extra={len(submitted_users - targets)}"
        )
    counts = normalized.groupby("uid").size()
    if not (counts == TOP_N).all():
        raise RankingValidationError(
            f"submission must contain exactly {TOP_N} rows for every target user"
        )
    if normalized.duplicated(["uid", "item_id"]).any():
        raise RankingValidationError(
            "submission contains duplicate (uid, item_id) pairs"
        )
    valid_ranks = set(range(1, TOP_N + 1))
    ranks_are_valid = normalized.groupby("uid")["rank"].apply(
        lambda values: set(map(int, values)) == valid_ranks
    )
    if not ranks_are_valid.all():
        raise RankingValidationError(
            f"each user must have every rank from 1 through {TOP_N} exactly once"
        )
    return normalized


def ranked_items(frame: pd.DataFrame) -> dict[int, list[int]]:
    """Convert a validated ranking frame to ordered items keyed by user.

    Args:
        frame: Frame that has passed :func:`validate_ranking`.

    Returns:
        A ``uid -> item IDs`` mapping ordered by ascending rank.
    """
    ordered = frame.sort_values(["uid", "rank"])
    return {
        int(uid): list(map(int, values))
        for uid, values in ordered.groupby("uid").item_id
    }


def ndcg_at_k(ranked: list[int], gold: dict[int, int], k: int) -> float:
    """Compute graded normalized discounted cumulative gain at ``k``.

    Relevance gain is ``2**grade - 1`` and the discount at one-based rank
    ``r`` is ``1 / log2(r + 1)``. Items absent from ``gold`` have grade zero.

    Args:
        ranked: Item IDs in predicted rank order.
        gold: Mapping from relevant item IDs to integer relevance grades.
        k: Maximum number of predicted positions to score.

    Returns:
        For a valid duplicate-free ranking, NDCG in ``[0, 1]``; returns
        ``0.0`` when the ideal gain is zero.
    """
    gains = np.asarray([gold.get(item, 0) for item in ranked[:k]], dtype=np.float64)
    discounts = 1.0 / np.log2(np.arange(2, len(gains) + 2))
    dcg = float(np.sum((np.power(2.0, gains) - 1.0) * discounts))
    ideal = np.asarray(sorted(gold.values(), reverse=True)[:k], dtype=np.float64)
    ideal_discounts = 1.0 / np.log2(np.arange(2, len(ideal) + 2))
    idcg = float(np.sum((np.power(2.0, ideal) - 1.0) * ideal_discounts))
    return dcg / idcg if idcg else 0.0


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

    Args:
        ranked: Ranked item IDs for every target user.
        graded: Relevant item grades keyed by user and item.

    Returns:
        The six-decimal ``quality_ndcg@10`` value and number of scored users.
    """
    quality = float(
        np.mean(
            [
                ndcg_at_k(ranked[uid], gold, QUALITY_K)
                for uid, gold in graded.items()
            ]
        )
    )
    return {
        "quality_ndcg@10": round(quality, 6),
        "quality_users": len(graded),
    }
----
#!/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>"
        )
    path = Path(sys.argv[1])
    ranked = load_submission(path, eligibility, targets)
    print(json.dumps({"model": str(path), "scores": score(ranked, graded)}, indent=2))


if __name__ == "__main__":
    main()
Harness context total tokens reminder
{
  "type": "total_tokens_reminder",
  "text": "<total_tokens>14982079 tokens left</total_tokens>"
}
03

Bash command

+00:10
Thinking unavailable No text recorded

The archive records a thinking event with empty text. No readable thinking is available for this event.

Tool callBashpython -c " Returned

Tool call · Input

python -c "
import pandas as pd, numpy as np, time
t=time.time()
tu=pd.read_parquet('/task/data/target_users.parquet'); print(tu.shape, tu.columns.tolist(), tu.head())
cc=pd.read_parquet('/task/data/candidate_catalog.parquet'); print(cc.shape, cc.columns.tolist(), cc.head())
ps=pd.read_parquet('/task/data/validation_preference_state.parquet'); print(ps.shape, ps.columns.tolist(), ps.head())
import pyarrow.parquet as pq
f=pq.ParquetFile('/task/data/train_listens.parquet'); print(f.metadata.num_rows, f.schema_arrow)
print(time.time()-t)
"

Tool response

(8456, 3) ['uid', 'recent_positive_listens', 'history_positive_listens']    uid  recent_positive_listens  history_positive_listens
0  100                    844.0                      2604
1  200                     50.0                       286
2  300                    168.0                       359
3  600                   1985.0                      2423
4  700                   1776.0                      6114
(30000, 4) ['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
(469124, 3) ['uid', 'item_id', 'state']    uid  item_id  state
0  100   410868  liked
1  100   732449  liked
2  100   982903  liked
3  100  1730273  liked
4  100  2621343  liked
43484159 uid: uint32
timestamp: uint32
item_id: uint32
is_organic: uint8
played_ratio_pct: uint16
track_length_seconds: uint32
-- schema metadata --
pandas: '{"index_columns": [], "column_indexes": [], "columns": [{"name":' + 797
0.07158136367797852
Tool callBashpython -c " Returned

Tool call · Input

python -c "
import numpy as np
z=np.load('/task/data/validation_eligible_candidates.npz')
print({k:(z[k].shape,z[k].dtype) for k in z.files})
p=z['packed_eligible']
m=np.unpackbits(p,axis=1,bitorder='little')[:, :len(z['item_ids'])]
print('elig per user', m.sum(1)[:10], m.sum(1).mean())
z2=np.load('/task/data/test_eligible_candidates.npz')
print({k:(z2[k].shape,z2[k].dtype) for k in z2.files})
print((z['uids']==z2['uids']).all(), (z['item_ids']==z2['item_ids']).all())
"

Tool response

{'uids': ((8456,), dtype('uint32')), 'item_ids': ((30000,), dtype('uint32')), 'packed_eligible': ((8456, 3750), dtype('uint8'))}
elig per user [29318 29832 29931 29320 28347 27476 29666 29501 28560 28736] 29067.306291390727
{'uids': ((8456,), dtype('uint32')), 'item_ids': ((30000,), dtype('uint32')), 'packed_eligible': ((8456, 3750), dtype('uint8'))}
True True
Harness context total tokens reminder
{
  "type": "total_tokens_reminder",
  "text": "<total_tokens>14973970 tokens left</total_tokens>"
}
04

Bash command

+00:24
Thinking unavailable No text recorded

The archive records a thinking event with empty text. No readable thinking is available for this event.

Tool callBashmkdir -p /app/solution && cd /app/solution && python -c " Returned

Tool call · Input

mkdir -p /app/solution && cd /app/solution && python -c "
import pyarrow.parquet as pq, numpy as np, pandas as pd, time
t=time.time()
tb=pq.read_table('/task/data/train_listens.parquet',columns=['uid','item_id','is_organic','played_ratio_pct','timestamp'])
print('read',time.time()-t, tb.num_rows)
d=tb.to_pandas(); del tb
print('pd',time.time()-t)
print('uniq users', d.uid.nunique())
cat=pd.read_parquet('/task/data/candidate_catalog.parquet')
ci=set(cat.item_id.values)
m=d.item_id.isin(ci)
print('in catalog frac', m.mean())
print('ts range', d.timestamp.min(), d.timestamp.max())
print(time.time()-t)
"

Tool response

read 0.3953073024749756 43484159
pd 0.512113094329834
uniq users 9238
in catalog frac 0.7186436099638032
ts range 0 24786795
5.475316762924194
Harness context total tokens reminder
{
  "type": "total_tokens_reminder",
  "text": "<total_tokens>14972379 tokens left</total_tokens>"
}
05

Bash command

+00:49
Thinking unavailable No text recorded

The archive records a thinking event with empty text. No readable thinking is available for this event.

Model text

Only 9238 users total — small enough for dense matrix work. Let me check repeat-vs-novel structure fast.

Tool callBashpython -c " Returned

Tool call · Input

python -c "
import pandas as pd, numpy as np, time
t=time.time()
cat=pd.read_parquet('/task/data/candidate_catalog.parquet')
items=cat.item_id.values.astype(np.int64)
z=np.load('/task/data/validation_eligible_candidates.npz')
print('catalog order == npz item order?', (z['item_ids'].astype(np.int64)==items).all())
tl=pd.read_parquet('/task/data/train_listens.parquet',columns=['uid','item_id','is_organic','played_ratio_pct'])
vl=pd.read_parquet('/task/data/val_listens.parquet',columns=['uid','item_id','is_organic','played_ratio_pct'])
vlk=pd.read_parquet('/task/data/val_likes.parquet',columns=['uid','item_id','is_organic'])
tu=set(pd.read_parquet('/task/data/target_users.parquet').uid)
rel=vl[(vl.is_organic==1)&(vl.played_ratio_pct>=80)][['uid','item_id']].drop_duplicates()
rel=rel[rel.uid.isin(tu)]
hist=tl[(tl.is_organic==1)&(tl.played_ratio_pct>=50)][['uid','item_id']].drop_duplicates()
h=set(map(tuple,hist.values))
r=np.array([ (u,i) in h for u,i in rel.values])
print('val strong listens', len(rel),'repeat frac', r.mean())
lk=vlk[(vlk.is_organic==1)&(vlk.uid.isin(tu))][['uid','item_id']].drop_duplicates()
print('val organic likes', len(lk), 'repeat frac', np.mean([ (u,i) in h for u,i in lk.values]))
ps=pd.read_parquet('/task/data/validation_preference_state.parquet')
pl=set(map(tuple, ps[ps.state=='liked'][['uid','item_id']].values))
print('rel in liked-state', np.mean([(u,i) in pl for u,i in rel.values]), 'likes in likedstate', np.mean([(u,i) in pl for u,i in lk.values]))
print(time.time()-t)
"

Tool response

catalog order == npz item order? True
val strong listens 255608 repeat frac 0.6247457043598009
val organic likes 17195 repeat frac 0.09985460889793545
rel in liked-state 0.2168946198867015 likes in likedstate 0.03908112823495202
6.50438666343689
Harness context total tokens reminder
{
  "type": "total_tokens_reminder",
  "text": "<total_tokens>14970363 tokens left</total_tokens>"
}
06

Write build.py

+01:28
Thinking unavailable No text recorded

The archive records a thinking event with empty text. No readable thinking is available for this event.

Model text

Now building the main pipeline.

Tool callWrite/app/solution/build.py Returned

Tool call · Input

/app/solution/build.py

"""Discovery ranker for the "Made for You" shelf.

Two stages:
  1. Feature construction from event history (repeat-consumption, explicit
     preference state, user-user CF, SVD item-item CF, popularity).
  2. A blend whose weights are tuned on the public validation window, then
     refit on train+val for the hidden test.
"""
from __future__ import annotations

import sys
import time

import numpy as np
import pandas as pd
import scipy.sparse as sp

DATA = "/task/data"
TRAIN_CUTOFF = 24786800
WEEK = 7 * 24 * 3600
T0 = time.time()


def log(*a):
    print(f"[{time.time()-T0:7.1f}s]", *a, flush=True)


def load_events(stage):
    """Return history frames for the given stage ('val' builds from train only)."""
    parts = ["train"] if stage == "val" else ["train", "val"]
    out = {}
    for fam, cols in [
        ("listens", ["uid", "timestamp", "item_id", "is_organic", "played_ratio_pct"]),
        ("likes", ["uid", "timestamp", "item_id", "is_organic"]),
        ("dislikes", ["uid", "timestamp", "item_id", "is_organic"]),
    ]:
        out[fam] = pd.concat(
            [pd.read_parquet(f"{DATA}/{p}_{fam}.parquet", columns=cols) for p in parts],
            ignore_index=True,
        )
    return out


def build(stage):
    """Build the dense (n_users x n_items) score-feature stack for one stage."""
    cat = pd.read_parquet(f"{DATA}/candidate_catalog.parquet")
    items = cat.item_id.values.astype(np.int64)
    n_items = len(items)
    item_pos = pd.Series(np.arange(n_items), index=items)

    npz = np.load(f"{DATA}/{'validation' if stage=='val' else 'test'}_eligible_candidates.npz")
    tgt_uids = npz["uids"].astype(np.int64)
    assert (npz["item_ids"].astype(np.int64) == items).all()
    elig = np.unpackbits(npz["packed_eligible"], axis=1, bitorder="little")[:, :n_items].astype(bool)
    n_tgt = len(tgt_uids)

    ev = load_events(stage)
    cutoff = TRAIN_CUTOFF if stage == "val" else TRAIN_CUTOFF + WEEK + 1800
    log(stage, "events loaded")

    li = ev["listens"]
    li = li[li.item_id.isin(item_pos.index)]
    li = li.assign(col=item_pos.reindex(li.item_id.values).values)

    all_uids = np.union1d(li.uid.unique().astype(np.int64), tgt_uids)
    urow = pd.Series(np.arange(len(all_uids)), index=all_uids)
    li = li.assign(row=urow.reindex(li.uid.values).values)

    strong = li[(li.is_organic == 1) & (li.played_ratio_pct >= 80)]
    pos = li[li.played_ratio_pct >= 50]

    # ---- global popularity (organic strong listens) ----
    pop = np.bincount(strong.col.values, minlength=n_items).astype(np.float32)
    pop_l = np.log1p(pop)
    pop_l /= pop_l.max()

    # ---- user x item history matrices ----
    def mat(df, w=None, n_rows=len(all_uids)):
        d = np.ones(len(df), np.float32) if w is None else w.astype(np.float32)
        m = sp.coo_matrix((d, (df.row.values, df.col.values)), shape=(n_rows, n_items)).tocsr()
        m.sum_duplicates()
        return m

    X_strong = mat(strong)                      # counts of strong organic listens
    X_pos = mat(pos)                            # any >=50% listen
    age = (cutoff - strong.timestamp.values).astype(np.float64)
    X_rec = mat(strong, np.exp(-age / (14 * 86400.0)))      # 14-day half-life-ish
    X_rec2 = mat(strong, np.exp(-age / (3 * 86400.0)))      # short-term
    log(stage, "history matrices", X_strong.nnz, X_pos.nnz)

    tgt_rows = urow.reindex(tgt_uids).values

    # ---- explicit preference state ----
    ps = pd.read_parquet(f"{DATA}/{'validation' if stage=='val' else 'test'}_preference_state.parquet")
    ps = ps[ps.item_id.isin(item_pos.index) & ps.uid.isin(set(tgt_uids))]
    trow = pd.Series(np.arange(n_tgt), index=tgt_uids)
    pr = trow.reindex(ps.uid.values).values
    pc = item_pos.reindex(ps.item_id.values).values
    liked = np.zeros((n_tgt, n_items), np.float32)
    disliked = np.zeros((n_tgt, n_items), np.float32)
    m = (ps.state == "liked").values
    liked[pr[m], pc[m]] = 1.0
    disliked[pr[~m], pc[~m]] = 1.0

    # ---- CF: user-user on cosine-normalised strong history ----
    Xn = X_strong.copy()
    Xn.data = np.log1p(Xn.data).astype(np.float32)
    norms = np.sqrt(Xn.multiply(Xn).sum(1)).A.ravel()
    norms[norms == 0] = 1.0
    Xn = sp.diags((1.0 / norms).astype(np.float32)) @ Xn
    Xn = Xn.astype(np.float32).tocsr()

    Xd = np.asarray(Xn.todense(), dtype=np.float32)
    sim = Xd[tgt_rows] @ Xd.T                      # (n_tgt x n_users)
    log(stage, "user-user sim", sim.shape)
    np.put_along_axis(sim, np.arange(len(tgt_rows))[:, None] * 0 + tgt_rows[:, None], 0.0, axis=1)
    K = 200
    idx = np.argpartition(-sim, K, axis=1)[:, :K]
    top = np.take_along_axis(sim, idx, axis=1)
    top = np.maximum(top, 0) ** 2
    rows = np.repeat(np.arange(n_tgt), K)
    Sk = sp.csr_matrix((top.ravel(), (rows, idx.ravel())), shape=sim.shape)
    del sim
    cf_uu = np.asarray((Sk @ Xn).todense(), dtype=np.float32)
    cf_uu /= cf_uu.max(1, keepdims=True).clip(1e-9)
    log(stage, "user-user CF done")

    # ---- CF: item-item over the same normalised matrix, low-rank ----
    from sklearn.utils.extmath import randomized_svd

    U, S, Vt = randomized_svd(Xn, n_components=192, n_iter=4, random_state=0)
    ii = (U[tgt_rows] * S) @ Vt
    ii /= np.abs(ii).max(1, keepdims=True).clip(1e-9)
    log(stage, "svd done")

    del Xd, Sk
    feats = {
        "pop": np.broadcast_to(pop_l, (n_tgt, n_items)).astype(np.float32),
        "rep": np.log1p(np.asarray(X_strong[tgt_rows].todense(), np.float32)),
        "rec": np.asarray(X_rec[tgt_rows].todense(), np.float32),
        "rec2": np.asarray(X_rec2[tgt_rows].todense(), np.float32),
        "posl": np.log1p(np.asarray(X_pos[tgt_rows].todense(), np.float32)),
        "liked": liked,
        "disliked": disliked,
        "cf_uu": cf_uu,
        "ii": ii.astype(np.float32),
    }
    for k in ("rep", "rec", "rec2", "posl"):
        feats[k] = feats[k] / feats[k].max(1, keepdims=True).clip(1e-9)
    log(stage, "features built")
    return dict(items=items, tgt_uids=tgt_uids, elig=elig, feats=feats)


def val_truth(items, tgt_uids, elig):
    item_pos = pd.Series(np.arange(len(items)), index=items)
    trow = pd.Series(np.arange(len(tgt_uids)), index=tgt_uids)
    grade = np.zeros((len(tgt_uids), len(items)), np.int8)
    vl = pd.read_parquet(f"{DATA}/val_listens.parquet")
    vk = pd.read_parquet(f"{DATA}/val_likes.parquet")
    for df, g in ((vl[(vl.is_organic == 1) & (vl.played_ratio_pct >= 80)], 1),
                  (vk[vk.is_organic == 1], 3)):
        df = df[df.uid.isin(set(tgt_uids)) & df.item_id.isin(item_pos.index)]
        grade[trow.reindex(df.uid.values).values, item_pos.reindex(df.item_id.values).values] = g
    grade[~elig] = 0
    return grade


def ndcg(score, grade, elig, k=10):
    s = np.where(elig, score, -np.inf)
    idx = np.argpartition(-s, k, axis=1)[:, :k]
    ordr = np.take_along_axis(s, idx, axis=1).argsort(axis=1)[:, ::-1]
    idx = np.take_along_axis(idx, ordr, axis=1)
    g = np.take_along_axis(grade, idx, axis=1).astype(np.float64)
    disc = 1.0 / np.log2(np.arange(2, k + 2))
    dcg = ((2.0 ** g - 1) * disc).sum(1)
    gs = -np.sort(-grade, axis=1)[:, :k].astype(np.float64)
    idcg = ((2.0 ** gs - 1) * disc).sum(1)
    m = idcg > 0
    return float(np.mean(dcg[m] / idcg[m])), int(m.sum())


def combine(feats, w):
    out = np.zeros_like(feats["pop"])
    for k, v in w.items():
        if v:
            out += np.float32(v) * feats[k]
    return out


def write_sub(res, score, path):
    elig, tgt_uids, items = res["elig"], res["tgt_uids"], res["items"]
    s = np.where(elig, score, -np.inf)
    idx = np.argpartition(-s, 100, axis=1)[:, :100]
    ordr = np.take_along_axis(s, idx, axis=1).argsort(axis=1)[:, ::-1]
    idx = np.take_along_axis(idx, ordr, axis=1)
    n = len(tgt_uids)
    df = pd.DataFrame({
        "uid": np.repeat(tgt_uids, 100),
        "item_id": items[idx.ravel()],
        "rank": np.tile(np.arange(1, 101), n),
    })
    assert np.take_along_axis(elig, idx, axis=1).all()
    df.to_parquet(path, index=False)
    log("wrote", path)


if __name__ == "__main__":
    np.save("/app/solution/_noop.npy", np.zeros(1))

Tool response

File created successfully at: /app/solution/build.py (file state is current in your context — no need to Read it back)
Harness context total tokens reminder
{
  "type": "total_tokens_reminder",
  "text": "<total_tokens>14964467 tokens left</total_tokens>"
}
07

Bash command

+02:07
Tool callBashpython -c " Returned

Tool call · Input

python -c "
import build as B, numpy as np, itertools, pickle
r=B.build('val')
g=B.val_truth(r['items'],r['tgt_uids'],r['elig'])
B.log('truth users', (g.max(1)>0).sum())
f=r['feats']
for k in f: 
    print(k, B.ndcg(np.ascontiguousarray(f[k]),g,r['elig']))
np.save('/app/solution/_valgrade.npy', g)
" 2>&1 | tail -30

Tool response

[    0.7s] val events loaded
[    5.3s] val history matrices 1950643 5564926
Harness context total tokens reminder
{
  "type": "total_tokens_reminder",
  "text": "<total_tokens>14964179 tokens left</total_tokens>"
}
08

Bash command

+02:21
Thinking unavailable No text recorded

The archive records a thinking event with empty text. No readable thinking is available for this event.

Tool callBashpython -c " Returned

Tool call · Input

python -c "
import build as B, numpy as np
r=B.build('val')
g=B.val_truth(r['items'],r['tgt_uids'],r['elig'])
B.log('truth users', (g.max(1)>0).sum())
f=r['feats']
for k in f:
    print(k, B.ndcg(np.ascontiguousarray(f[k]),g,r['elig']), flush=True)
np.save('/app/solution/_valgrade.npy', g)
import pickle; pickle.dump(r, open('/app/solution/_val.pkl','wb'), protocol=4)
"; echo EXIT=$?

Tool response

[    0.8s] val events loaded
[    5.1s] val history matrices 1950643 5564926
/bin/bash: line 21:  8204 Killed                  python -c "
import build as B, numpy as np
r=B.build('val')
g=B.val_truth(r['items'],r['tgt_uids'],r['elig'])
B.log('truth users', (g.max(1)>0).sum())
f=r['feats']
for k in f:
    print(k, B.ndcg(np.ascontiguousarray(f[k]),g,r['elig']), flush=True)
np.save('/app/solution/_valgrade.npy', g)
import pickle; pickle.dump(r, open('/app/solution/_val.pkl','wb'), protocol=4)
"
EXIT=137
Harness context total tokens reminder
{
  "type": "total_tokens_reminder",
  "text": "<total_tokens>14963584 tokens left</total_tokens>"
}
09

Bash command

+02:36
Thinking unavailable No text recorded

The archive records a thinking event with empty text. No readable thinking is available for this event.

Tool callBashpython - <<'EOF' Returned

Tool call · Input

python - <<'EOF'
import re
s=open('build.py').read()
s=s.replace("""    X_strong = mat(strong)                      # counts of strong organic listens
    X_pos = mat(pos)                            # any >=50% listen
    age = (cutoff - strong.timestamp.values).astype(np.float64)
    X_rec = mat(strong, np.exp(-age / (14 * 86400.0)))      # 14-day half-life-ish
    X_rec2 = mat(strong, np.exp(-age / (3 * 86400.0)))      # short-term
    log(stage, "history matrices", X_strong.nnz, X_pos.nnz)
""","""    X_strong = mat(strong)                      # counts of strong organic listens
    X_pos = mat(pos)                            # any >=50% listen
    age = (cutoff - strong.timestamp.values).astype(np.float64)
    X_rec = mat(strong, np.exp(-age / (14 * 86400.0)))      # 14-day half-life-ish
    X_rec2 = mat(strong, np.exp(-age / (3 * 86400.0)))      # short-term
    log(stage, "history matrices", X_strong.nnz, X_pos.nnz)
    del ev, li, strong, pos
""")
s=s.replace("""    feats = {
        "pop": np.broadcast_to(pop_l, (n_tgt, n_items)).astype(np.float32),
        "rep": np.log1p(np.asarray(X_strong[tgt_rows].todense(), np.float32)),
        "rec": np.asarray(X_rec[tgt_rows].todense(), np.float32),
        "rec2": np.asarray(X_rec2[tgt_rows].todense(), np.float32),
        "posl": np.log1p(np.asarray(X_pos[tgt_rows].todense(), np.float32)),
        "liked": liked,
        "disliked": disliked,
        "cf_uu": cf_uu,
        "ii": ii.astype(np.float32),
    }
    for k in ("rep", "rec", "rec2", "posl"):
        feats[k] = feats[k] / feats[k].max(1, keepdims=True).clip(1e-9)
""","""    feats = {
        "pop": np.broadcast_to(pop_l, (n_tgt, n_items)),
        "rep": np.log1p(np.asarray(X_strong[tgt_rows].todense(), np.float32)),
        "rec": np.asarray(X_rec[tgt_rows].todense(), np.float32),
        "rec2": np.asarray(X_rec2[tgt_rows].todense(), np.float32),
        "posl": np.log1p(np.asarray(X_pos[tgt_rows].todense(), np.float32)),
        "liked": liked,
        "disliked": disliked,
        "cf_uu": cf_uu,
        "ii": ii.astype(np.float32),
    }
    del X_strong, X_pos, X_rec, X_rec2, Xn, U, S, Vt, ii
    for k in ("rep", "rec", "rec2", "posl"):
        feats[k] /= feats[k].max(1, keepdims=True).clip(1e-9)
""")
s=s.replace("""    del Xd, Sk
""","""    del Xd, Sk, U, S, Vt
""").replace("    del X_strong, X_pos, X_rec, X_rec2, Xn, U, S, Vt, ii","    del X_strong, X_pos, X_rec, X_rec2, Xn, ii")
open('build.py','w').write(s)
EOF
grep -n "del " build.py

Tool response

90:    del ev, li, strong, pos
124:    del sim
137:    del Xd, Sk, U, S, Vt
149:    del X_strong, X_pos, X_rec, X_rec2, Xn, ii
Harness context edited text file
{
  "type": "edited_text_file",
  "filename": "/app/solution/build.py",
  "snippet": "1\t\"\"\"Discovery ranker for the \"Made for You\" shelf.\n2\t\n3\tTwo stages:\n4\t  1. Feature construction from event history (repeat-consumption, explicit\n5\t     preference state, user-user CF, SVD item-item CF, popularity).\n6\t  2. A blend whose weights are tuned on the public validation window, then\n7\t     refit on train+val for the hidden test.\n8\t\"\"\"\n9\tfrom __future__ import annotations\n10\t\n11\timport sys\n12\timport time\n13\t\n14\timport numpy as np\n15\timport pandas as pd\n16\timport scipy.sparse as sp\n17\t\n18\tDATA = \"/task/data\"\n19\tTRAIN_CUTOFF = 24786800\n20\tWEEK = 7 * 24 * 3600\n21\tT0 = time.time()\n22\t\n23\t\n24\tdef log(*a):\n25\t    print(f\"[{time.time()-T0:7.1f}s]\", *a, flush=True)\n26\t\n27\t\n28\tdef load_events(stage):\n29\t    \"\"\"Return history frames for the given stage ('val' builds from train only).\"\"\"\n30\t    parts = [\"train\"] if stage == \"val\" else [\"train\", \"val\"]\n31\t    out = {}\n32\t    for fam, cols in [\n33\t        (\"listens\", [\"uid\", \"timestamp\", \"item_id\", \"is_organic\", \"played_ratio_pct\"]),\n34\t        (\"likes\", [\"uid\", \"timestamp\", \"item_id\", \"is_organic\"]),\n35\t        (\"dislikes\", [\"uid\", \"timestamp\", \"item_id\", \"is_organic\"]),\n36\t    ]:\n37\t        out[fam] = pd.concat(\n38\t            [pd.read_parquet(f\"{DATA}/{p}_{fam}.parquet\", columns=cols) for p in parts],\n39\t            ignore_index=True,\n40\t        )\n41\t    return out\n42\t\n43\t\n44\tdef build(stage):\n45\t    \"\"\"Build the dense (n_users x n_items) score-feature stack for one stage.\"\"\"\n46\t    cat = pd.read_parquet(f\"{DATA}/candidate_catalog.parquet\")\n47\t    items = cat.item_id.values.astype(np.int64)\n48\t    n_items = len(items)\n49\t    item_pos = pd.Series(np.arange(n_items), index=items)\n50\t\n51\t    npz = np.load(f\"{DATA}/{'validation' if stage=='val' else 'test'}_eligible_candidates.npz\")\n52\t    tgt_uids = npz[\"uids\"].astype(np.int64)\n53\t    assert (npz[\"item_ids\"].astype(np.int64) == items).all()\n54\t    elig = np.unpackbits(npz[\"packed_eligible\"], axis=1, bitorder=\"little\")[:, :n_items].astype(bool)\n55\t    n_tgt = len(tgt_uids)\n56\t\n57\t    ev = load_events(stage)\n58\t    cutoff = TRAIN_CUTOFF if stage == \"val\" else TRAIN_CUTOFF + WEEK + 1800\n59\t    log(stage, \"events loaded\")\n60\t\n61\t    li = ev[\"listens\"]\n62\t    li = li[li.item_id.isin(item_pos.index)]\n63\t    li = li.assign(col=item_pos.reindex(li.item_id.values).values)\n64\t\n65\t    all_uids = np.union1d(li.uid.unique().astype(np.int64), tgt_uids)\n66\t    urow = pd.Series(np.arange(len(all_uids)), index=all_uids)\n67\t    li = li.assign(row=urow.reindex(li.uid.values).values)\n68\t\n69\t    strong = li[(li.is_organic == 1) & (li.played_ratio_pct >= 80)]\n70\t    pos = li[li.played_ratio_pct >= 50]\n71\t\n72\t    # ---- global popularity (organic strong listens) ----\n73\t    pop = np.bincount(strong.col.values, minlength=n_items).astype(np.float32)\n74\t    pop_l = np.log1p(pop)\n75\t    pop_l /= pop_l.max()\n76\t\n77\t    # ---- user x item history matrices ----\n78\t    def mat(df, w=None, n_rows=len(all_uids)):\n79\t        d = np.ones(len(df), np.float32) if w is None else w.astype(np.float32)\n80\t        m = sp.coo_matrix((d, (df.row.values, df.col.values)), shape=(n_rows, n_items)).tocsr()\n81\t        m.sum_duplicates()\n82\t        return m\n83\t\n84\t    X_strong = mat(strong)                      # counts of strong organic listens\n85\t    X_pos = mat(pos)                            # any >=50% listen\n86\t    age = (cutoff - strong.timestamp.values).astype(np.float64)\n87\t    X_rec = mat(strong, np.exp(-age / (14 * 86400.0)))      # 14-day half-life-ish\n88\t    X_rec2 = mat(strong, np.exp(-age / (3 * 86400.0)))      # short-term\n89\t    log(stage, \"history matrices\", X_strong.nnz, X_pos.nnz)\n90\t    del ev, li, strong, pos\n91\t\n92\t    tgt_rows = urow.reindex(tgt_uids).values\n93\t\n94\t    # ---- explicit preference state ----\n95\t    ps = pd.read_parquet(f\"{DATA}/{'validation' if stage=='val' else 'test'}_preference_state.parquet\")\n96\t    ps = ps[ps.item_id.isin(item_pos.index) & ps.uid.isin(set(tgt_uids))]\n97\t    trow = pd.Series(np.arange(n_tgt), index=tgt_uids)\n98\t    pr = trow.reindex(ps.uid.values).values\n99\t    pc = item_pos.reindex(ps.item_id.values).values\n100\t    liked = np.zeros((n_tgt, n_items), np.float32)\n101\t    disliked = np.zeros((n_tgt, n_items), np.float32)\n102\t    m = (ps.state == \"liked\").values\n103\t    liked[pr[m], pc[m]] = 1.0\n104\t    disliked[pr[~m], pc[~m]] = 1.0\n105\t\n106\t    # ---- CF: user-user on cosine-normalised strong history ----\n107\t    Xn = X_strong.copy()\n108\t    Xn.data = np.log1p(Xn.data).astype(np.float32)\n109\t    norms = np.sqrt(Xn.multiply(Xn).sum(1)).A.ravel()\n110\t    norms[norms == 0] = 1.0\n111\t    Xn = sp.diags((1.0 / norms).astype(np.float32)) @ Xn\n112\t    Xn = Xn.astype(np.float32).tocsr()\n113\t\n114\t    Xd = np.asarray(Xn.todense(), dtype=np.float32)\n115\t    sim = Xd[tgt_rows] @ Xd.T                      # (n_tgt x n_users)\n116\t    log(stage, \"user-user sim\", sim.shape)\n117\t    np.put_along_axis(sim, np.arange(len(tgt_rows))[:, None] * 0 + tgt_rows[:, None], 0.0, axis=1)\n118\t    K = 200\n119\t    idx = np.argpartition(-sim, K, axis=1)[:, :K]\n120\t    top = np.take_along_axis(sim, idx, axis=1)\n121\t    top = np.maximum(top, 0) ** 2\n122\t    rows = np.repeat(np.arange(n_tgt), K)\n123\t    Sk = sp.csr_matrix((top.ravel(), (rows, idx.ravel())), shape=sim.shape)\n124\t    del sim\n125\t    cf_uu = np.asarray((Sk @ Xn).todense(), dtype=np.float32)\n126\t    cf_uu /= cf_uu.max(1, keepdims=True).clip(1e-9)\n127\t    log(stage, \"user-user CF done\")\n128\t\n129\t    # ---- CF: item-item over the same normalised matrix, low-rank ----\n130\t    from sklearn.utils.extmath import randomized_svd\n131\t\n132\t    U, S, Vt = randomized_svd(Xn, n_components=192, n_iter=4, random_state=0)\n133\t    ii = (U[tgt_rows] * S) @ Vt\n134\t    ii /= np.abs(ii).max(1, keepdims=True).clip(1e-9)\n135\t    log(stage, \"svd done\")\n136\t\n137\t    del Xd, Sk, U, S, Vt\n138\t    feats = {\n139\t        \"pop\": np.broadcast_to(pop_l, (n_tgt, n_items)),\n140\t        \"rep\": np.log1p(np.asarray(X_strong[tgt_rows].todense(), np.float32)),\n141\t        \"rec\": np.asarray(X_rec[tgt_rows].todense(), np.float32),\n142\t        \"rec2\": np.asarray(X_rec2[tgt_rows].todense(), np.float32),\n143\t        \"posl\": np.log1p(np.asarray(X_pos[tgt_rows].todense(), np.float32)),\n144\t        \"liked\": liked,\n145\t        \"disliked\": disliked,\n146\t        \"cf_uu\": cf_uu,\n147\t        \"ii\": ii.astype(np.float32),\n148\t    }\n149\t    del X_strong, X_pos, X_rec, X_rec2, Xn, ii\n150\t    for k in (\"rep\", \"rec\", \"rec2\", \"posl\"):\n151\t        feats[k] /= feats[k].max(1, keepdims=True).clip(1e-9)\n152\t    log(stage, \"features built\")\n153\t    return dict(items=items, tgt_uids=tgt_uids, elig=elig, feats=feats)\n154\t\n155\t\n156\tdef val_truth(items, tgt_uids, elig):\n157\t    item_pos = pd.Series(np.arange(len(items)), index=items)\n158\t    trow = pd.Series(np.arange(len(tgt_uids)), index=tgt_uids)\n159\t    grade = np.zeros((len(tgt_uids), len(items)), np.int8)\n160\t    vl = pd.read_parquet(f\"{DATA}/val_listens.parquet\")\n161\t    vk = pd.read_parquet(f\"{DATA}/val_likes.parquet\")\n162\t    for df, g in ((vl[(vl.is_organic == 1) & (vl.played_ratio_pct >= 80)], 1),\n163\t                  (vk[vk.is_organic == 1], 3)):\n164\t        df = df[df.uid.isin(set(tgt_uids)) & df.item_id.isin(item_pos.index)]\n165\t        grade[trow.reindex(df.uid.values).values, item_pos.reindex(df.item_id.values).values] = g\n166\t    grade[~elig] = 0\n167\t    return grade\n168\t\n169\t\n170\tdef ndcg(score, grade, elig, k=10):\n171\t    s = np.where(elig, score, -np.inf)\n172\t    idx = np.argpartition(-s, k, axis=1)[:, :k]\n173\t    ordr = np.take_along_axis(s, idx, axis=1).argsort(axis=1)[:, ::-1]\n174\t    idx = np.take_along_axis(idx, ordr, axis=1)\n175\t    g = np.take_along_axis(grade, idx, axis=1).astype(np.float64)\n176\t    disc = 1.0 / np.log2(np.arange(2, k + 2))\n177\t    dcg = ((2.0 ** g - 1) * disc).sum(1)\n178\t    gs = -np.sort(-grade, axis=1)[:, :k].astype(np.float64)\n179\t    idcg = ((2.0 ** gs - 1) * disc).sum(1)\n180\t    m = idcg > 0\n181\t    return float(np.mean(dcg[m] / idcg[m])), int(m.sum())\n182\t\n183\t\n184\tdef combine(feats, w):\n185\t    out = np.zeros_like(feats[\"pop\"])\n186\t    for k, v in w.items():\n187\t        if v:\n188\t            out += np.float32(v) * feats[k]\n189\t    return out\n190\t\n191\t\n\n... [19 lines truncated] ..."
}
Harness context total tokens reminder
{
  "type": "total_tokens_reminder",
  "text": "<total_tokens>14961725 tokens left</total_tokens>"
}
10

Bash command

+02:55
Thinking unavailable No text recorded

The archive records a thinking event with empty text. No readable thinking is available for this event.

Tool callBashpython - <<'EOF' Returned

Tool call · Input

python - <<'EOF'
s=open('build.py').read()
s=s.replace("""    liked = np.zeros((n_tgt, n_items), np.float32)
    disliked = np.zeros((n_tgt, n_items), np.float32)
    m = (ps.state == "liked").values
    liked[pr[m], pc[m]] = 1.0
    disliked[pr[~m], pc[~m]] = 1.0""",
"""    m = (ps.state == "liked").values
    liked = (pr[m], pc[m])
    disliked = (pr[~m], pc[~m])""")
s=s.replace("""        "rec2": np.asarray(X_rec2[tgt_rows].todense(), np.float32),
        "posl": np.log1p(np.asarray(X_pos[tgt_rows].todense(), np.float32)),
        "liked": liked,
        "disliked": disliked,
        "cf_uu": cf_uu,""","""        "rec2": np.asarray(X_rec2[tgt_rows].todense(), np.float32),
        "cf_uu": cf_uu,""")
s=s.replace('    for k in ("rep", "rec", "rec2", "posl"):','    for k in ("rep", "rec", "rec2"):')
s=s.replace('    return dict(items=items, tgt_uids=tgt_uids, elig=elig, feats=feats)',
            '    return dict(items=items, tgt_uids=tgt_uids, elig=elig, feats=feats,\n                liked=liked, disliked=disliked, pop=pop_l)')
s=s.replace('''def combine(feats, w):
    out = np.zeros_like(feats["pop"])
    for k, v in w.items():
        if v:
            out += np.float32(v) * feats[k]
    return out''','''def combine(res, w, out=None):
    """Linear blend of the dense features plus sparse explicit-state terms."""
    f = res["feats"]
    if out is None:
        out = np.zeros((len(res["tgt_uids"]), len(res["items"])), np.float32)
    else:
        out[:] = 0
    out += np.float32(w.get("pop", 0.0)) * res["pop"]
    for k in ("rep", "rec", "rec2", "cf_uu", "ii"):
        v = w.get(k, 0.0)
        if v:
            out += np.float32(v) * f[k]
    if w.get("liked"):
        np.add.at(out, res["liked"], np.float32(w["liked"]))
    if w.get("disliked"):
        np.add.at(out, res["disliked"], np.float32(w["disliked"]))
    return out''')
open('build.py','w').write(s)
EOF
grep -n "feats = {" -A 12 build.py

Tool response

136:    feats = {
137-        "pop": np.broadcast_to(pop_l, (n_tgt, n_items)),
138-        "rep": np.log1p(np.asarray(X_strong[tgt_rows].todense(), np.float32)),
139-        "rec": np.asarray(X_rec[tgt_rows].todense(), np.float32),
140-        "rec2": np.asarray(X_rec2[tgt_rows].todense(), np.float32),
141-        "cf_uu": cf_uu,
142-        "ii": ii.astype(np.float32),
143-    }
144-    del X_strong, X_pos, X_rec, X_rec2, Xn, ii
145-    for k in ("rep", "rec", "rec2"):
146-        feats[k] /= feats[k].max(1, keepdims=True).clip(1e-9)
147-    log(stage, "features built")
148-    return dict(items=items, tgt_uids=tgt_uids, elig=elig, feats=feats,
Harness context total tokens reminder
{
  "type": "total_tokens_reminder",
  "text": "<total_tokens>14955792 tokens left</total_tokens>"
}
11

Write tune.py

+03:05
Thinking unavailable No text recorded

The archive records a thinking event with empty text. No readable thinking is available for this event.

Tool callWrite/app/solution/tune.py Returned

Tool call · Input

/app/solution/tune.py

"""Tune blend weights on the public validation window, then refit for test."""
import gc
import json

import numpy as np

import build as B

res = B.build("val")
grade = B.val_truth(res["items"], res["tgt_uids"], res["elig"])
B.log("labelled users", int((grade.max(1) > 0).sum()))
gc.collect()

buf = np.zeros((len(res["tgt_uids"]), len(res["items"])), np.float32)
disc = 1.0 / np.log2(np.arange(2, 12))
gs = -np.sort(-grade, axis=1)[:, :10].astype(np.float64)
IDCG = ((2.0 ** gs - 1) * disc).sum(1)
MASK = IDCG > 0
del gs


def score_of(w):
    s = B.combine(res, w, out=buf)
    s[~res["elig"]] = -np.inf
    idx = np.argpartition(-s, 10, axis=1)[:, :10]
    ordr = np.take_along_axis(s, idx, axis=1).argsort(axis=1)[:, ::-1]
    idx = np.take_along_axis(idx, ordr, axis=1)
    g = np.take_along_axis(grade, idx, axis=1).astype(np.float64)
    dcg = ((2.0 ** g - 1) * disc).sum(1)
    return float(np.mean(dcg[MASK] / IDCG[MASK]))


for k in ("pop", "rep", "rec", "rec2", "cf_uu", "ii", "liked"):
    B.log("solo", k, round(score_of({k: 1.0}), 5))

w = {"pop": 0.05, "rep": 1.0, "rec": 0.5, "rec2": 0.3, "cf_uu": 0.3, "ii": 0.2,
     "liked": 0.3, "disliked": -0.5}
best = score_of(w)
B.log("init", best, w)
GRID = {
    "pop": [0.0, 0.02, 0.05, 0.1, 0.2, 0.4],
    "rep": [0.0, 0.25, 0.5, 1.0, 2.0],
    "rec": [0.0, 0.25, 0.5, 1.0, 2.0, 4.0],
    "rec2": [0.0, 0.15, 0.3, 0.6, 1.2, 2.5],
    "cf_uu": [0.0, 0.1, 0.2, 0.4, 0.8, 1.6],
    "ii": [0.0, 0.05, 0.1, 0.2, 0.4, 0.8],
    "liked": [0.0, 0.1, 0.2, 0.4, 0.8],
    "disliked": [0.0, -0.2, -0.5, -2.0],
}
for sweep in range(3):
    improved = False
    for k, vals in GRID.items():
        cur = w[k]
        for v in vals:
            if v == cur:
                continue
            w[k] = v
            s = score_of(w)
            if s > best + 1e-6:
                best, cur, improved = s, v, True
            w[k] = cur
        w[k] = cur
    B.log("sweep", sweep, round(best, 5), w)
    if not improved:
        break

json.dump({"weights": w, "val_ndcg@10": best}, open("/app/solution/weights.json", "w"), indent=2)
B.log("BEST", best, w)

s = B.combine(res, w, out=buf)
B.write_sub(res, s, "/app/solution/validation.parquet")
del res, grade, buf, s
gc.collect()

test = B.build("test")
s = B.combine(test, w)
B.write_sub(test, s, "/app/solution/submission.parquet")
B.log("done")

Tool response

File created successfully at: /app/solution/tune.py (file state is current in your context — no need to Read it back)
Harness context total tokens reminder
{
  "type": "total_tokens_reminder",
  "text": "<total_tokens>14953965 tokens left</total_tokens>"
}
12

Bash command

+03:18
Tool callBashnohup python -u tune.py > tune.log 2>&1 & Returned

Tool call · Input

nohup python -u tune.py > tune.log 2>&1 &
echo started; sleep 60; tail -20 tune.log; free -g | head -2

Tool response

started
/bin/bash: line 3:  8242 Killed                  nohup python -u tune.py > tune.log 2>&1
[    0.7s] val events loaded
[    5.1s] val history matrices 1950643 5564926
[   27.3s] val user-user sim (8456, 9221)
[   31.6s] val user-user CF done
[   34.8s] val svd done
[   36.1s] val features built
[   36.5s] labelled users 4263
               total        used        free      shared  buff/cache   available
Mem:              15           1           8           0           5          14
Harness context total tokens reminder
{
  "type": "total_tokens_reminder",
  "text": "<total_tokens>14953798 tokens left</total_tokens>"
}
13

Bash command

+04:28
Thinking unavailable No text recorded

The archive records a thinking event with empty text. No readable thinking is available for this event.

Tool callBashcat /sys/fs/cgroup/memory.max 2>/dev/null || cat /sys/fs/cgroup/memory/memory.limit_in_bytes 2>/dev/null; echo; cat /sys/fs/cgroup/memory.peak 2>/dev/null Returned

Tool call · Input

cat /sys/fs/cgroup/memory.max 2>/dev/null || cat /sys/fs/cgroup/memory/memory.limit_in_bytes 2>/dev/null; echo; cat /sys/fs/cgroup/memory.peak 2>/dev/null

Tool response

8589934592

8589934592
Harness context total tokens reminder
{
  "type": "total_tokens_reminder",
  "text": "<total_tokens>14952850 tokens left</total_tokens>"
}
14

Bash command

+04:35
Thinking unavailable No text recorded

The archive records a thinking event with empty text. No readable thinking is available for this event.

Tool callBashpython - <<'EOF' Returned

Tool call · Input

python - <<'EOF'
s=open('build.py').read()
s=s.replace('''    for k in ("rep", "rec", "rec2"):
        feats[k] /= feats[k].max(1, keepdims=True).clip(1e-9)''',
'''    for k in ("rep", "rec", "rec2"):
        feats[k] /= feats[k].max(1, keepdims=True).clip(1e-9)
    for k in ("rep", "rec", "rec2", "cf_uu", "ii"):
        feats[k] = feats[k].astype(np.float16)   # 8 GiB cgroup budget
        gc.collect()''')
s=s.replace('''    Xd = np.asarray(Xn.todense(), dtype=np.float32)
    sim = Xd[tgt_rows] @ Xd.T''','''    Xd = np.asarray(Xn.todense(), dtype=np.float32)
    sim = np.ascontiguousarray(Xd[tgt_rows]) @ Xd.T''')
s=s.replace("import sys\nimport time","import gc\nimport time")
s=s.replace('''    U, S, Vt = randomized_svd(Xn, n_components=192, n_iter=4, random_state=0)''',
'''    del Xd
    gc.collect()
    U, S, Vt = randomized_svd(Xn, n_components=192, n_iter=4, random_state=0)''')
s=s.replace("    del Xd, Sk, U, S, Vt","    del Sk, U, S, Vt\n    gc.collect()")
open('build.py','w').write(s)
EOF
sed -i 's/^import json$/import json\nimport gc/' tune.py; python -c "import ast;ast.parse(open('/app/solution/build.py').read())" && echo OK
nohup python -u tune.py > tune.log 2>&1 &
sleep 75; tail -25 tune.log

Tool response

OK
[    0.7s] val events loaded
[    5.1s] val history matrices 1950643 5564926
[   27.4s] val user-user sim (8456, 9221)
[   31.7s] val user-user CF done
[   34.9s] val svd done
[   41.0s] val features built
[   41.3s] labelled users 4263
[   45.0s] solo pop 0.01055
[   53.0s] solo rep 7e-05
[   61.0s] solo rec 7e-05
[   69.0s] solo rec2 7e-05
[   71.7s] solo cf_uu 0.0219
[   73.9s] solo ii 0.02245
Harness context edited text file
{
  "type": "edited_text_file",
  "filename": "/app/solution/tune.py",
  "snippet": "1\t\"\"\"Tune blend weights on the public validation window, then refit for test.\"\"\"\n2\timport gc\n3\timport json\n4\timport gc\n5\t\n6\timport numpy as np\n7\t\n8\timport build as B\n9\t\n10\tres = B.build(\"val\")\n11\tgrade = B.val_truth(res[\"items\"], res[\"tgt_uids\"], res[\"elig\"])\n12\tB.log(\"labelled users\", int((grade.max(1) > 0).sum()))"
}
Harness context total tokens reminder
{
  "type": "total_tokens_reminder",
  "text": "<total_tokens>14951728 tokens left</total_tokens>"
}
15

Bash command

+06:10
Thinking unavailable No text recorded

The archive records a thinking event with empty text. No readable thinking is available for this event.

Model text

Important finding: eligibility excludes the user's own history — this is a pure discovery task, so repeat features are worthless and CF quality is everything.

Tool callBashsleep 50; tail -8 tune.log Returned

Tool call · Input

sleep 50; tail -8 tune.log

Tool response

[   45.0s] solo pop 0.01055
[   53.0s] solo rep 7e-05
[   61.0s] solo rec 7e-05
[   69.0s] solo rec2 7e-05
[   71.7s] solo cf_uu 0.0219
[   73.9s] solo ii 0.02245
[   81.2s] solo liked 7e-05
[   86.7s] init 0.023518388985170727 {'pop': 0.05, 'rep': 1.0, 'rec': 0.5, 'rec2': 0.3, 'cf_uu': 0.3, 'ii': 0.2, 'liked': 0.3, 'disliked': -0.5}
Harness context total tokens reminder
{
  "type": "total_tokens_reminder",
  "text": "<total_tokens>14950021 tokens left</total_tokens>"
}
16

Bash command

+07:09
Thinking unavailable No text recorded

The archive records a thinking event with empty text. No readable thinking is available for this event.

Tool callBashpkill -f tune.py; cat > /app/solution/tune2.py <<'EOF' Error

Tool call · Input

pkill -f tune.py; cat > /app/solution/tune2.py <<'EOF'
"""Lean weight search (discovery-only features) + final artifacts."""
import gc, json
import numpy as np
import build as B

def prep(res, grade):
    disc = 1.0 / np.log2(np.arange(2, 12))
    gs = -np.sort(-grade, axis=1)[:, :10].astype(np.float64)
    idcg = ((2.0 ** gs - 1) * disc).sum(1); m = idcg > 0
    del gs; gc.collect()
    return disc, idcg, m

res = B.build("val")
grade = B.val_truth(res["items"], res["tgt_uids"], res["elig"])
disc, IDCG, MASK = prep(res, grade)
buf = np.zeros(grade.shape, np.float32)
NEG = res["elig"] == False

def score_of(w):
    s = B.combine(res, w, out=buf)
    s[NEG] = -np.inf
    idx = np.argpartition(-s, 10, axis=1)[:, :10]
    o = np.take_along_axis(s, idx, axis=1).argsort(axis=1)[:, ::-1]
    g = np.take_along_axis(grade, np.take_along_axis(idx, o, axis=1), axis=1).astype(np.float64)
    return float(np.mean(((2.0 ** g - 1) * disc).sum(1)[MASK] / IDCG[MASK]))

w = {"pop": 0.05, "cf_uu": 0.5, "ii": 0.5, "disliked": -1.0}
best = score_of(w); B.log("init", round(best, 5))
GRID = {"cf_uu": [0.2, 0.35, 0.5, 0.8, 1.2], "ii": [0.2, 0.35, 0.5, 0.8, 1.2],
        "pop": [0.0, 0.02, 0.05, 0.12, 0.25], "disliked": [0.0, -1.0]}
for sweep in range(2):
    for k, vals in GRID.items():
        cur = w[k]
        for v in vals:
            if v == cur: continue
            w[k] = v; s = score_of(w)
            if s > best + 1e-6: best, cur = s, v
            w[k] = cur
        w[k] = cur
    B.log("sweep", sweep, round(best, 5), w)
json.dump({"weights": w, "val_ndcg@10": best}, open("/app/solution/weights.json", "w"), indent=2)
B.log("BEST", best, w)
B.write_sub(res, B.combine(res, w, out=buf), "/app/solution/validation.parquet")
del res, grade, buf, NEG; gc.collect()
test = B.build("test")
B.write_sub(test, B.combine(test, w), "/app/solution/submission.parquet")
B.log("done")
EOF
nohup python -u tune2.py > tune2.log 2>&1 &
sleep 100; tail -12 tune2.log

Tool response · Tool error

Exit code 144
Harness context total tokens reminder
{
  "type": "total_tokens_reminder",
  "text": "<total_tokens>14948232 tokens left</total_tokens>"
}
17

Bash command

+07:19
Tool callBashsleep 45; tail -12 /app/solution/tune2.log Error

Tool call · Input

sleep 45; tail -12 /app/solution/tune2.log

Tool response · Tool error

Exit code 1
tail: cannot open '/app/solution/tune2.log' for reading: No such file or directory
Harness context total tokens reminder
{
  "type": "total_tokens_reminder",
  "text": "<total_tokens>14948123 tokens left</total_tokens>"
}
18

Bash command

+08:07
Thinking unavailable No text recorded

The archive records a thinking event with empty text. No readable thinking is available for this event.

Tool callBashpgrep -af python | head; ls /app/solution/ Returned

Tool call · Input

pgrep -af python | head; ls /app/solution/

Tool response

8327 /bin/bash -c source /logs/agent/sessions/shell-snapshots/snapshot-bash-1790235893615-teb25c.sh 2>/dev/null || true && shopt -u extglob 2>/dev/null || true && { \builtin unalias -- 'unsetenv'; \builtin unset -f -- 'unsetenv'; } >/dev/null 2>&1 || true && eval 'pgrep -af python | head; ls /app/solution/' < /dev/null && pwd -P >| /tmp/claude-8d43-cwd
build.py
tune.log
tune.py
Harness context total tokens reminder
{
  "type": "total_tokens_reminder",
  "text": "<total_tokens>14947877 tokens left</total_tokens>"
}
19

Bash command

+08:16
Tool callBashcat > tune2.py <<'PYEOF' Returned

Tool call · Input

cat > tune2.py <<'PYEOF'
"""Lean weight search (discovery-only features) + final artifacts."""
import gc, json
import numpy as np
import build as B

res = B.build("val")
grade = B.val_truth(res["items"], res["tgt_uids"], res["elig"])
disc = 1.0 / np.log2(np.arange(2, 12))
gs = -np.sort(-grade, axis=1)[:, :10].astype(np.float64)
IDCG = ((2.0 ** gs - 1) * disc).sum(1); MASK = IDCG > 0
del gs; gc.collect()
buf = np.zeros(grade.shape, np.float32)
NEG = ~res["elig"]

def score_of(w):
    s = B.combine(res, w, out=buf)
    s[NEG] = -np.inf
    idx = np.argpartition(-s, 10, axis=1)[:, :10]
    o = np.take_along_axis(s, idx, axis=1).argsort(axis=1)[:, ::-1]
    g = np.take_along_axis(grade, np.take_along_axis(idx, o, axis=1), axis=1).astype(np.float64)
    return float(np.mean(((2.0 ** g - 1) * disc).sum(1)[MASK] / IDCG[MASK]))

w = {"pop": 0.05, "cf_uu": 0.5, "ii": 0.5, "disliked": -1.0}
best = score_of(w); B.log("init", round(best, 5))
GRID = {"cf_uu": [0.2, 0.35, 0.8, 1.2], "ii": [0.2, 0.35, 0.8, 1.2],
        "pop": [0.0, 0.02, 0.12, 0.25], "disliked": [0.0]}
for sweep in range(2):
    for k, vals in GRID.items():
        cur = w[k]
        for v in vals:
            if v == cur: continue
            w[k] = v; s = score_of(w)
            if s > best + 1e-6: best, cur = s, v
            w[k] = cur
        w[k] = cur
    B.log("sweep", sweep, round(best, 5), w)
json.dump({"weights": w, "val_ndcg@10": best}, open("/app/solution/weights.json", "w"), indent=2)
B.log("BEST", best, w)
B.write_sub(res, B.combine(res, w, out=buf), "/app/solution/validation.parquet")
del res, grade, buf, NEG; gc.collect()
test = B.build("test")
B.write_sub(test, B.combine(test, w), "/app/solution/submission.parquet")
B.log("done")
PYEOF
nohup python -u tune2.py > tune2.log 2>&1 &
sleep 90; tail -12 tune2.log

Tool response

/bin/bash: line 93:  8335 Killed                  nohup python -u tune2.py > tune2.log 2>&1
[    0.7s] val events loaded
[    5.1s] val history matrices 1950643 5564926
[   27.2s] val user-user sim (8456, 9221)
[   31.6s] val user-user CF done
[   34.8s] val svd done
[   41.1s] val features built
Harness context total tokens reminder
{
  "type": "total_tokens_reminder",
  "text": "<total_tokens>14946639 tokens left</total_tokens>"
}
20

Bash command

+09:57
Thinking unavailable No text recorded

The archive records a thinking event with empty text. No readable thinking is available for this event.

Tool callBashpython - <<'EOF' Returned

Tool call · Input

python - <<'EOF'
s=open('build.py').read()
s=s.replace('''    X_pos = mat(pos)                            # any >=50% listen
    age = (cutoff - strong.timestamp.values).astype(np.float64)
    X_rec = mat(strong, np.exp(-age / (14 * 86400.0)))      # 14-day half-life-ish
    X_rec2 = mat(strong, np.exp(-age / (3 * 86400.0)))      # short-term
    log(stage, "history matrices", X_strong.nnz, X_pos.nnz)
    del ev, li, strong, pos''','''    log(stage, "history matrix", X_strong.nnz)
    del ev, li, strong, pos
    gc.collect()''')
s=s.replace('''        "rep": np.log1p(np.asarray(X_strong[tgt_rows].todense(), np.float32)),
        "rec": np.asarray(X_rec[tgt_rows].todense(), np.float32),
        "rec2": np.asarray(X_rec2[tgt_rows].todense(), np.float32),
        "cf_uu"''','''        "cf_uu"''')
s=s.replace('''    del X_strong, X_pos, X_rec, X_rec2, Xn, ii
    for k in ("rep", "rec", "rec2"):
        feats[k] /= feats[k].max(1, keepdims=True).clip(1e-9)
    for k in ("rep", "rec", "rec2", "cf_uu", "ii"):''','''    del X_strong, Xn, ii
    for k in ("cf_uu", "ii"):''')
s=s.replace('    for k in ("rep", "rec", "rec2", "cf_uu", "ii"):\n        v = w.get','    for k in ("cf_uu", "ii"):\n        v = w.get')
open('build.py','w').write(s)
EOF
grep -n "X_pos\|X_rec\|rep\|rec2" build.py; python -c "import ast;ast.parse(open('build.py').read())" && echo SYNTAX_OK

Tool response

4:  1. Feature construction from event history (repeat-consumption, explicit
117:    rows = np.repeat(np.arange(n_tgt), K)
205:        "uid": np.repeat(tgt_uids, 100),
SYNTAX_OK
Harness context total tokens reminder
{
  "type": "total_tokens_reminder",
  "text": "<total_tokens>14945071 tokens left</total_tokens>"
}
21

Bash command

+10:12
Tool callBashcat > final.py <<'PYEOF' Returned

Tool call · Input

cat > final.py <<'PYEOF'
"""Fit the discovery ranker and write the hidden-test submission (test first)."""
import gc, json, sys
import numpy as np
import build as B

W = {"pop": 0.05, "cf_uu": 0.5, "ii": 0.5, "disliked": -1.0}
test = B.build("test")
B.write_sub(test, B.combine(test, W), "/app/solution/submission.parquet")
del test; gc.collect()
B.log("submission written")

res = B.build("val")
grade = B.val_truth(res["items"], res["tgt_uids"], res["elig"])
disc = 1.0 / np.log2(np.arange(2, 12))
IDCG = ((2.0 ** (-np.sort(-grade, axis=1)[:, :10].astype(np.float64)) - 1) * disc).sum(1)
MASK = IDCG > 0
gc.collect()
buf = np.zeros(grade.shape, np.float32)
NEG = ~res["elig"]

def score_of(w):
    s = B.combine(res, w, out=buf)
    s[NEG] = -np.inf
    idx = np.argpartition(-s, 10, axis=1)[:, :10]
    o = np.take_along_axis(s, idx, axis=1).argsort(axis=1)[:, ::-1]
    g = np.take_along_axis(grade, np.take_along_axis(idx, o, axis=1), axis=1).astype(np.float64)
    return float(np.mean(((2.0 ** g - 1) * disc).sum(1)[MASK] / IDCG[MASK]))

w = dict(W); best = score_of(w); B.log("init", round(best, 5))
for k, vals in {"cf_uu": [0.2, 0.35, 0.8, 1.5], "ii": [0.2, 0.35, 0.8, 1.5],
                "pop": [0.0, 0.02, 0.12, 0.3]}.items():
    cur = w[k]
    for v in vals:
        w[k] = v; s = score_of(w)
        B.log(" ", k, v, round(s, 5))
        if s > best + 1e-6: best, cur = s, v
        w[k] = cur
    w[k] = cur
json.dump({"weights": w, "val_ndcg@10": best, "baseline_weights": W},
          open("/app/solution/weights.json", "w"), indent=2)
B.log("BEST", best, w)
B.write_sub(res, B.combine(res, w, out=buf), "/app/solution/validation.parquet")
if w != W:
    del res, grade, buf, NEG; gc.collect()
    test = B.build("test")
    B.write_sub(test, B.combine(test, w), "/app/solution/submission.parquet")
B.log("done")
PYEOF
nohup python -u final.py > final.log 2>&1 &
sleep 80; tail -15 final.log; ls -la /app/solution/

Tool response

[    1.0s] test events loaded
[    3.6s] test history matrix 2008203
[   25.8s] test user-user sim (8456, 9223)
[   30.2s] test user-user CF done
[   33.4s] test svd done
[   35.7s] test features built
[   39.1s] wrote /app/solution/submission.parquet
[   39.1s] submission written
[   39.6s] val events loaded
[   42.2s] val history matrix 1950643
[   64.4s] val user-user sim (8456, 9221)
[   68.7s] val user-user CF done
[   71.5s] val svd done
[   73.8s] val features built
total 1660
drwxr-xr-x 1 agent agent    4096 Sep 24 07:55 .
drwxr-xr-x 1 agent agent    4096 Sep 24 07:41 ..
-rw-r--r-- 1 agent agent    8036 Sep 24 07:54 build.py
-rw-r--r-- 1 agent agent     478 Sep 24 07:56 final.log
-rw-r--r-- 1 agent agent    1809 Sep 24 07:55 final.py
-rw-r--r-- 1 agent agent 1652876 Sep 24 07:55 submission.parquet
-rw-r--r-- 1 agent agent     573 Sep 24 07:50 tune.log
-rw-r--r-- 1 agent agent    2358 Sep 24 07:49 tune.py
-rw-r--r-- 1 agent agent     206 Sep 24 07:53 tune2.log
-rw-r--r-- 1 agent agent    1705 Sep 24 07:53 tune2.py
Harness context total tokens reminder
{
  "type": "total_tokens_reminder",
  "text": "<total_tokens>14943909 tokens left</total_tokens>"
}
22

Write README.md

+11:34
Thinking unavailable No text recorded

The archive records a thinking event with empty text. No readable thinking is available for this event.

Model text

Submission is on disk. Writing the README while the weight sweep runs.

Tool callWrite/app/solution/README.md Returned

Tool call · Input

/app/solution/README.md

# "Made for You" discovery ranker

`python final.py` builds `submission.parquet` (hidden test) and
`validation.parquet` (public window); `build.py` holds the model.

## Key observation

The supplied candidate eligibility masks out each user's *own* interaction
history (~900 items/user). Measured on the public window, repeat-consumption
features (past strong-listen counts, recency-decayed counts, `liked`
preference state) score NDCG@10 ≈ 7e-5 on their own — they rank items that are
never eligible. This is a pure **discovery** problem, so the model is entirely
collaborative-filtering driven and those features were dropped.

## Model

History = organic listens completed to ≥80 % (the objective's own positive
definition), as a user × item count matrix `X` over the 30 000-track catalog,
`log1p`-damped and L2-row-normalised (`Xn`).

Three scores are blended linearly:

| Feature | Definition |
| --- | --- |
| `cf_uu` | User-user CF: cosine neighbours over `Xn`, self-similarity zeroed, top-200 neighbours, weights squared to sharpen, then propagated back through `Xn`. Row-max normalised. |
| `ii` | Low-rank item-item CF: rank-192 randomised SVD of `Xn`, reconstructed scores. Row-max normalised. |
| `pop` | Global organic strong-listen popularity, `log1p`, max-normalised — a prior for thin users. |

Plus a `disliked` penalty applied to active explicit-dislike pairs from the
stage's preference-state file.

Weights are chosen by coordinate ascent directly on validation NDCG@10
(`weights.json` records the result). Solo validation NDCG@10: `ii` 0.0225,
`cf_uu` 0.0219, `pop` 0.0106 — the blend beats all three.

## Stage handling

`build("val")` uses only `train_*` as history and the validation preference
state / eligibility. `build("test")` refits the identical pipeline on
`train_* + val_*` with the test preference state and test eligibility, so the
validation week is observed history rather than a label source. Recency decay
is anchored to each stage's own cutoff.

## Caveats

Fit under a 30-minute wall clock and an 8 GiB memory cap: dense
(8456 × 30 000) feature planes are stored as float16, which bounds the feature
count. Given more time the obvious next steps are a full item-item cosine with
popularity damping / EASE-style closed form, and a GBDT reranker over a top-300
prefilter trained on a pseudo-validation split carved from the tail of train.

Tool response

File created successfully at: /app/solution/README.md (file state is current in your context — no need to Read it back)
Harness context total tokens reminder
{
  "type": "total_tokens_reminder",
  "text": "<total_tokens>14942287 tokens left</total_tokens>"
}
23

Bash command

+11:48
Tool callBashsleep 60; tail -20 final.log Returned

Tool call · Input

sleep 60; tail -20 final.log

Tool response

[   79.6s] init 0.02438
[   82.8s]   cf_uu 0.2 0.02418
[   86.0s]   cf_uu 0.35 0.02407
[   89.1s]   cf_uu 0.8 0.02401
[   92.3s]   cf_uu 1.5 0.02308
[   95.5s]   ii 0.2 0.0234
[   98.7s]   ii 0.35 0.02416
[  101.9s]   ii 0.8 0.02406
[  105.0s]   ii 1.5 0.02391
[  108.4s]   pop 0.0 0.02442
[  111.6s]   pop 0.02 0.02461
[  114.8s]   pop 0.12 0.02402
[  118.0s]   pop 0.3 0.02226
[  118.0s] BEST 0.02461460816228665 {'pop': 0.02, 'cf_uu': 0.5, 'ii': 0.5, 'disliked': -1.0}
[  121.4s] wrote /app/solution/validation.parquet
[  122.1s] test events loaded
[  124.8s] test history matrix 2008203
[  146.8s] test user-user sim (8456, 9223)
[  151.2s] test user-user CF done
[  154.1s] test svd done
Harness context total tokens reminder
{
  "type": "total_tokens_reminder",
  "text": "<total_tokens>14942165 tokens left</total_tokens>"
}
24

Bash command

+12:50
Thinking unavailable No text recorded

The archive records a thinking event with empty text. No readable thinking is available for this event.

Tool callBashsleep 20; tail -3 final.log && python /task/evaluate_public.py /app/solution/validation.parquet Returned

Tool call · Input

sleep 20; tail -3 final.log && python /task/evaluate_public.py /app/solution/validation.parquet

Tool response

[  156.4s] test features built
[  159.7s] wrote /app/solution/submission.parquet
[  159.7s] done
{
  "model": "/app/solution/validation.parquet",
  "scores": {
    "quality_ndcg@10": 0.024615,
    "quality_users": 4263
  }
}
Harness context total tokens reminder
{
  "type": "total_tokens_reminder",
  "text": "<total_tokens>14941556 tokens left</total_tokens>"
}
25

Bash command

+13:18
Tool callBashrm -f tune.py tune2.py tune.log tune2.log _noop.npy && python -c " Returned

Tool call · Input

rm -f tune.py tune2.py tune.log tune2.log _noop.npy && python -c "
import pandas as pd,numpy as np
from ranking_evaluation import CandidateSet, validate_ranking, read_ranking
import sys; sys.path.insert(0,'/task')
d=pd.read_parquet('submission.parquet'); print(d.shape, d.dtypes.to_dict())
t=set(pd.read_parquet('/task/data/target_users.parquet').uid.astype(int))
f=validate_ranking(d,t)
cs=CandidateSet('/task/data/test_eligible_candidates.npz')
el=np.unpackbits(cs.packed,axis=1,bitorder='little')[:,:30000].astype(bool)
row={int(u):r for r,u in enumerate(cs.uids)}; col={int(i):c for c,i in enumerate(cs.item_ids)}
r=np.array([row[u] for u in f.uid]); c=np.array([col[i] for i in f.item_id])
print('all eligible:', el[r,c].all())
print(d.head(3))
" 2>&1 | tail -20; ls -la /app/solution

Tool response

Traceback (most recent call last):
  File "<string>", line 3, in <module>
ModuleNotFoundError: No module named 'ranking_evaluation'
total 3276
drwxr-xr-x 1 agent agent    4096 Sep 24 07:58 .
drwxr-xr-x 1 agent agent    4096 Sep 24 07:41 ..
-rw-r--r-- 1 agent agent    2390 Sep 24 07:56 README.md
-rw-r--r-- 1 agent agent    8036 Sep 24 07:54 build.py
-rw-r--r-- 1 agent agent    1268 Sep 24 07:57 final.log
-rw-r--r-- 1 agent agent    1809 Sep 24 07:55 final.py
-rw-r--r-- 1 agent agent 1656496 Sep 24 07:57 submission.parquet
-rw-r--r-- 1 agent agent 1656816 Sep 24 07:57 validation.parquet
-rw-r--r-- 1 agent agent     231 Sep 24 07:57 weights.json
Harness context total tokens reminder
{
  "type": "total_tokens_reminder",
  "text": "<total_tokens>14940973 tokens left</total_tokens>"
}
26

Bash command

+13:23
Tool callBashPYTHONPATH=/task python -c " Returned

Tool call · Input

PYTHONPATH=/task python -c "
import pandas as pd,numpy as np
from ranking_evaluation import CandidateSet, validate_ranking
d=pd.read_parquet('/app/solution/submission.parquet'); print(d.shape, d.dtypes.to_dict())
t=set(pd.read_parquet('/task/data/target_users.parquet').uid.astype(int))
f=validate_ranking(d,t); print('schema OK')
cs=CandidateSet('/task/data/test_eligible_candidates.npz')
el=np.unpackbits(cs.packed,axis=1,bitorder='little')[:,:30000].astype(bool)
row={int(u):r for r,u in enumerate(cs.uids)}; col={int(i):c for c,i in enumerate(cs.item_ids)}
r=np.array([row[u] for u in f.uid]); c=np.array([col[i] for i in f.item_id])
print('all eligible:', bool(el[r,c].all()))
"

Tool response

(845600, 3) {'uid': dtype('int64'), 'item_id': dtype('int64'), 'rank': dtype('int64')}
schema OK
all eligible: True
Harness context total tokens reminder
{
  "type": "total_tokens_reminder",
  "text": "<total_tokens>14940198 tokens left</total_tokens>"
}
27

Final response

+13:35

Model text

Done. /app/solution/submission.parquet is written and validated: 845,600 rows (8,456 users × 100), ranks 1–100 with no ties or duplicates, and every item eligible under test_eligible_candidates.npz.

Public validation NDCG@10: 0.024615 (4,263 scored users).

The decisive finding shaped the whole model: the supplied eligibility masks exclude each user's own interaction history (~900 items/user). Repeat-consumption features — past strong-listen counts, recency-decayed counts, liked preference state — each score ≈7e-5 solo, because they rank items that are never eligible. This is a pure discovery problem, so I dropped them and put everything into collaborative filtering.

Final model is a linear blend over organic ≥80%-completion listens (the objective's own positive definition), log1p-damped and L2-row-normalized:

FeatureSolo val NDCG@10Weight
ii — rank-192 randomized SVD item-item0.02250.5
cf_uu — top-200 user-user cosine neighbors, squared weights0.02190.5
pop — global organic popularity prior0.01060.02
disliked penalty from preference state—−1.0

Weights came from coordinate ascent on validation NDCG@10. The blend beats every component alone. Validation features use train_* only; the test artifact refits the identical pipeline on train_* + val_* with test-stage preference state and eligibility.

Two things worth flagging:

  • The absolute score is low because the task is genuinely hard — with the user's own history excluded, the model must predict which of ~29k unseen tracks a user will organically seek out in a seven-day window.
  • I ran against an 8 GiB cgroup cap (not the 15 GiB the host reports), which forced float16 storage for the dense 8456×30000 feature planes and bounded how many features I could hold at once. Two OOM kills cost time mid-attempt.

Not attempted, in priority order if there were more time: a full item-item cosine with popularity damping or EASE-style closed form (the SVD is a low-rank approximation of this and was the strongest single feature), and a GBDT reranker over a top-300 prefilter trained on a pseudo-validation split carved from the tail of train. Both are noted in the README.

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
yambda-opus-high-2026-09-24-00-34-15-04330cf-2
Recorded model
claude-opus-5
Harness version
2.1.251
Session
a50c4b12-382c-439f-ba44-72ef0a341448
Source SHA-256
fa9fb6647b9edfdd659b17aa4f8530f59f92c6281cf42679c331094cd37a15d2

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.