Module codec 

Dual-phase VectorCodec trait — the seam that makes future quantization algorithms drop-in additions rather than engine rewrites.

Upper-layer routing (HNSW navigation, beam expansion) calls fast_symmetric_distance on bitwise/heuristic kernels. Base-layer rerank calls exact_asymmetric_distance with full ADC + scalar correction + sparse outlier resolution.

Structs

AdcLut

Asymmetric Distance Computation lookup table — used by codecs that pre-decompose the query into per-subspace distance tables (PQ, IVF-PQ, TurboQuant). Consumed by base-layer rerank kernels via AVX2 pshufb or AVX-512 vpermb.

Traits

VectorCodec

The dual-phase quantization codec trait.