{"record":{"id":"0d891657c47c4dea","repo":"rohitg00/ai-engineering-from-scratch","slug":"weights-length-must-match-rankings-length","errorCode":null,"errorMessage":"weights length must match rankings length","messagePattern":"weights length must match rankings length","errorType":"validation","errorClass":"ValueError","httpStatus":null,"severity":"error","filePath":"phases/19-capstone-projects/65-hybrid-retrieval-bm25-dense/code/main.py","lineNumber":151,"sourceCode":"        qv = mock_embed(query)\n        scored = [(d, cosine(qv, v)) for d, v in self.vectors]\n        scored.sort(key=lambda x: -x[1])\n        return scored[:k]\n\n\n# ---------------------------------------------------------------------------\n# Reciprocal Rank Fusion\n# ---------------------------------------------------------------------------\n\ndef rrf(\n    rankings: list[list[tuple[Doc, float]]],\n    k: int = 60,\n    weights: list[float] | None = None,\n) -> list[tuple[Doc, float]]:\n    if weights is None:\n        weights = [1.0] * len(rankings)\n    if len(weights) != len(rankings):\n        raise ValueError(\"weights length must match rankings length\")\n    score: dict[str, float] = defaultdict(float)\n    by_id: dict[str, Doc] = {}\n    for w, ranks in zip(weights, rankings):\n        for rank, (doc, _) in enumerate(ranks):\n            score[doc.doc_id] += w * (1.0 / (k + rank + 1))\n            by_id[doc.doc_id] = doc\n    fused = sorted(score.items(), key=lambda x: -x[1])\n    return [(by_id[did], s) for did, s in fused]\n\n\n# ---------------------------------------------------------------------------\n# Hybrid retriever\n# ---------------------------------------------------------------------------\n\n@dataclass\nclass HybridRetriever:\n    bm25: BM25Index = field(default_factory=BM25Index)\n    dense: DenseIndex = field(default_factory=DenseIndex)","sourceCodeStart":133,"sourceCodeEnd":169,"githubUrl":"https://github.com/rohitg00/ai-engineering-from-scratch/blob/39ea8a1c6d0b61f071226eff7ede4d4105fed820/phases/19-capstone-projects/65-hybrid-retrieval-bm25-dense/code/main.py#L133-L169","documentation":"Error \"weights length must match rankings length\" thrown in rohitg00/ai-engineering-from-scratch.","triggerScenarios":"Thrown at phases/19-capstone-projects/65-hybrid-retrieval-bm25-dense/code/main.py:151 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":[],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"39ea8a1c6d0b61f071226eff7ede4d4105fed820","analyzedAt":"2026-08-26T03:13:46.626Z","schemaVersion":2},"datasetVersion":"2026-08-26T07:17:17.940Z"}