Dinesh Reddy ThimmasaniBuilding RAG, ML systems, and more from scratch — writeups and code.https://dineshreddythimmasani.com/Building RAG From Scratch, Part 1: TF-IDF, BM25, and Why BM25 Still Winshttps://dineshreddythimmasani.com/blog/rag-from-scratch-01-tfidf-bm25/https://dineshreddythimmasani.com/blog/rag-from-scratch-01-tfidf-bm25/Lexical retrieval from scratch, no sklearn: TF-IDF, BM25, worked hand calculations, and a head-to-head comparison showing exactly where BM25 beats TF-IDF and why.Thu, 01 Oct 2026 18:30:00 GMT