Citadel - Vendored PRISM filtered-ANN core
==========================================

This directory vendors source files from the PRISM project (prism-ann),
originally authored by Yuriy Peysakhov and licensed under the Apache
License, Version 2.0.

Upstream:
  https://github.com/yp3y5akh0v/prism

Original copyright:
  Copyright 2025 Yuriy Peysakhov

Vendored files (from `crates/prism-core/src/` of upstream):
  binary.rs   - Hamming-distance binary codes for pre-filter
  construct.rs - Index build: per-cell Vamana + greedy cross-partition + random overlay
  distance.rs - L2 / Inner / Hamming SIMD kernels (cosine added by Citadel)
  filter.rs   - Conjunctive attribute constraint matching
  graph.rs    - CSR graph adjacency
  io.rs       - Dataset loaders (fvecs, bvecs, ivecs)
  ivf.rs      - IVF^2 index for YFCC-style filtered search at scale
  partition.rs - PartitionTree (attribute-grouped cells)
  point.rs    - PointStore (flat vectors + attribute columns)
  quantize.rs - SQ8 scalar quantization
  search.rs   - Filtered search: regime routing + MQCB batch search

Modifications by Citadel are marked at the top of each modified file.
Citadel modifications: Copyright (c) Citadel contributors. Released
under the Apache License, Version 2.0.
