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Apr 11, 2026 · Artificial Intelligence

Understanding Vector Similarity Search: Flat Index, IVF, and HNSW

This article explains why vector databases are needed for semantic search of unstructured data and provides a detailed, step‑by‑step comparison of three core vector similarity algorithms—cosine similarity, Flat Index, IVF, and HNSW—highlighting their trade‑offs in accuracy and speed.