Reranking

Introduction Retrieval‑augmented generation (RAG) has become the de‑facto pattern for building LLM‑powered applications that need up‑to‑date, factual, or domain‑specific knowledge. By coupling a retriever (which fetches relevant documents) with a generator (which synthesizes a response), RAG mitigates hallucination, reduces latency, and lowers inference cost compared with prompting a massive model on raw text alone. While academic prototypes often rely on a single vector store and a simple similarity search, production deployments quickly hit limits: ...

Table of Contents Introduction Why Context Windows Matter Fundamentals of Semantic Chunking 3.1 Chunk Size vs. Token Budget 3.2 Semantic vs. Syntactic Splitting Advanced Reranking Strategies 4.1 Embedding‑Based Similarity 4.2 Cross‑Encoder Rerankers 4.3 Hybrid Approaches End‑to‑End Pipeline Architecture 5.1 Pre‑processing Layer 5.2 Chunk Retrieval & Scoring 5.3 Dynamic Context Assembly Implementation Walk‑through (Python) 6.1 Libraries & Setup 6.2 Semantic Chunker Example 6.3 Reranking with a Cross‑Encoder 6.4 Putting It All Together Performance Considerations & Benchmarks Best Practices for Production Systems Conclusion Resources Introduction Large language models (LLMs) have become the backbone of modern AI‑driven applications, from chat assistants to code generation tools. Yet, one of the most practical bottlenecks remains the context window—the maximum number of tokens an LLM can attend to in a single inference pass. While newer architectures push this limit from 2 k to 128 k tokens, most commercial deployments still operate under tighter constraints (e.g., 4 k–8 k tokens) due to latency, memory, and cost considerations. ...