BM25 · Hybrid · Rerank · Eval
SKUs, IDs, exact terms · rank_bm25 code
BGE / E5 / OpenAI · FAISS index
BM25 + dense parallel · $\\frac{1}{k+rank}$
Top-50 recall → cross-encoder → Top-5
hybrid → rerank → dedupe → LLM
Recall@k · MRR · faithfulness · context recall
4 configs × 20 questions → pick winner
Scroll lab: course-full-retrieval.html#retrieval-practice
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