Similarity Search Patterns Patterns for implementing efficient similarity search in production systems. When to Use This Skill - Building semantic search systems - Implementing RAG retrieval - Creating recommendation engines - Optimizing search latency - Scaling to millions of vectors - Combining semantic and keyword search Core Concepts 1. Distance Metrics | Metric | Formula | Best For | |--------|---------|----------| | Cosine | 1 - (A·B)/(‖A‖‖B‖) | Normalized embeddings | | Euclidean (L2) | √Σ(a-b)² | Raw embeddings | | Dot Product | A·B | Magnitude matters | | Manhattan (L1) | Σ|a-b| | Sp…