Skip to main content

COMPEL Glossary / index-algorithm

Index algorithm

The data-structure choice — HNSW, IVF, product quantization (PQ), or flat (brute-force) — that governs a vector store's query latency, memory footprint, and recall-at-k tradeoff.

What this means in practice

Selection is an architectural decision with implications for cost, scale, and update frequency; no index is universally best.

Synonyms

ANN index , vector index algorithm

See also

  • Vector store — A governed index of embeddings — numeric vector representations of text, image, or multimodal content — that supports similarity search used by retrieval-augmented generation.
  • Hybrid retrieval — A retrieval pattern combining dense (vector-based, e.g., dense passage retrieval) and sparse (term-based, e.g., BM25) retrieval methods, whose candidate sets are fused — typically via reciprocal rank fusion — before reranking.
  • Reranker — A cross-encoder model that re-scores a candidate set of documents — typically the top-k from an initial vector or hybrid retrieval — to improve ordering by the actual query-document semantic match.