What problem does it solve? Performing nearest-neighbor search over millions or billions of embedding vectors is too slow with brute-force approaches, and choosing the wrong index type wastes memory or sacrifices accuracy. This Skill provides guidance and code patterns for building, training, tuning, and persisting FAISS indexes for fast k-NN retrieval. ## Core Features & Use Cases - Index Type Selection: Covers Flat (exact), IVF (clustered approximate), HNSW (graph-based), and PQ (memory-compressed) indexes with guidance on when to use each based on dataset size. - GPU Acceleration: Shows how to move indexes to single or multiple GPUs for 10-100x speedups on large datasets. - Framework Integration: Includes LangChain and LlamaIndex integration patterns for RAG pipelines, plus index save/load for persistence. - Use Case: You are building a semantic search feature over 5 million document embeddings. Use this Skill to create an HNSW index, tune efSearch for the right speed/accuracy balance, and persist the trained index to disk. ## Quick Start Ask the AI to create a FAISS index for your embedding vectors and run a k-nearest-neighbor search with the appropriate index type for your dataset size.