Retrieval-Augmented Generation (RAG)
What is RAG?
Retrieval-Augmented Generation (RAG) combines the power of LLMs with external knowledge retrieval. Instead of relying only on the model’s training data, RAG retrieves relevant information and includes it in the prompt.
The Problem RAG Solves
Standard LLM:
- Limited to training data (knowledge cutoff)
- Cannot access your private documents
- May hallucinate facts
- Cannot cite sources
RAG-Enhanced LLM:
- Accesses current information
- Works with YOUR data
- Grounded in retrieved facts
- Can cite sources
How RAG Works
User Query → Retrieve Relevant Docs → Augment Prompt → Generate ResponseDetailed Flow:
-
User asks a question: “What are the library’s hours?”
-
Retrieve relevant documents:
- Convert query to embedding
- Search vector database
- Find most similar documents
-
Augment the prompt:
Context: [Retrieved docs about library hours] Question: What are the library's hours? Answer based on the context: -
Generate response:
- LLM reads context
- Generates accurate, grounded answer
- Can cite specific sources
Key Components
1. Retriever
Finds relevant information:
- Embedding model (nomic-embed-text)
- Vector database (ChromaDB)
- Similarity search
2. Generator
Produces the final response:
- Chat model (Llama 3.2)
- Context-aware prompting
- Structured output
RAG Benefits
✓ Accuracy: Grounded in actual documents ✓ Current Information: Add new docs anytime ✓ Privacy: Your data stays local ✓ Citations: Can reference sources ✓ Smaller Models: External knowledge supplements model ✓ Domain-Specific: Works with specialized content
What You’ll Learn
RAG vs. Fine-Tuning
| Aspect | RAG | Fine-Tuning |
|---|---|---|
| Setup | Quick, add documents | Slow, requires training |
| Updates | Add new docs anytime | Retrain entire model |
| Data Requirements | Any amount | Large datasets needed |
| Cost | Low (storage only) | High (compute for training) |
| Privacy | Fully local | Fully local (if done locally) |
| Best For | Dynamic knowledge, Q&A | Specialized tasks, style |
Use RAG when: You need to work with changing information or specific documents