Module search_reranking 

Post-RRF Reranking Pipeline for code-aware search.

Scientific foundations:

• Cormack et al. (SIGIR 2009): RRF as unsupervised fusion baseline
• Carbonell & Goldstein (SIGIR 1998): MMR diversity via file-saturation decay
• CoRNStack (ICLR 2025): Definition-boost + noise filtering for code
• SACL (EMNLP 2025): Query-type-adaptive weighting + path enrichment
• SweRank (2025): Multi-stage retrieve-then-rerank for code localization

Pipeline order (applied after RRF fusion):

1. Definition Boost — chunks defining the queried symbol rank higher
2. File Coherence — files with multiple relevant chunks get boosted
3. Noise Penalties — test/legacy/compat paths get penalized
4. MMR Diversity — exponential decay per file prevents single-file dominance

Enums

QueryType

Functions

classify_query

Classify a search query as Symbol, NL, or Architecture.

rerank_pipeline

Apply the full post-RRF reranking pipeline.

resolve_weights

Resolve BM25 vs Dense weight based on query type. Returns (bm25_weight, dense_weight).