Here are a few catchy titles, under 50 characters, for the provided content: * **Build a RAG Pipeline: A Guide** * **RAG with Embeddings: Step-by-Step** * **Custom RAG: From Docs to Answers**

Here's a 2-line summary of the article: This article provides a comprehensive guide to building a custom Retrieval-Augmented Generation (RAG) pipeline using embeddings for enhanced information retrieval. It outlines a step-by-step process, covering data preparation, embedding generation, vector database setup, query processing, contextualization, and evaluation, along with considerations for tool selection and advanced techniques. ```html Building</span></span> <span id="ctl00_ContentPlaceHolder1_labeltext"></span> <br /> <table id="ctl00_ContentPlaceHolder1_RepComments" cellspacing="0" border="0"> <tr> <td> </td> </tr><tr> <td> <span id="ctl00_ContentPlaceHolder1_RepComments_ctl01_labeltext"><font color="Black" size="4">```html <!DOCTYPE html> <html> <head> <title>Building a Custom RAG Pipeline with Embeddings

Introduction to RAG and Embeddings

Retrieval-Augmented Generation (RAG) is a powerful technique that combines the strengths of information retrieval and large language models (LLMs). It allows LLMs to access and utilize external knowledge sources, enabling them to generate more accurate, relevant, and up-to-date responses. This article guides you through building a custom RAG pipeline, leveraging embeddings for effective document retrieval. Embeddings are numerical representations of text that capture semantic meaning, allowing for efficient similarity searches.

Building a Custom RAG Pipeline: A Step-by-Step Guide

Step Description Tools/Technologies Code Snippet (Illustrative - Python)
1 Data Preparation and Chunking
This involves preparing your data source (e.g., documents, PDFs, web pages). The text is extracted and then split into smaller, manageable chunks. Chunking is crucial for efficient retrieval; the size of the chunks affects the context window of the LLM and the granularity of the retrieval.
  • Text extraction libraries (e.g., PyPDF2, Beautiful Soup)
  • Text splitting libraries (e.g., LangChain, spaCy)
          
import PyPDF2
from langchain.text_splitter import RecursiveCharacterTextSplitter

def load_pdf(file_path):
    with open(file_path, 'rb') as file:
        reader = PyPDF2.PdfReader(file)
        text = ""
        for page in reader.pages:
            text += page.extract_text()
    return text

def chunk_text(text, chunk_size=1000, chunk_overlap=100):
    text_splitter = RecursiveCharacterTextSplitter(chunk_size=chunk_size, chunk_overlap=chunk_overlap)
    chunks = text_splitter.split_text(text)
    return chunks

# Example usage:
pdf_text = load_pdf("your_document.pdf")
chunks = chunk_text(pdf_text)
print(f"Number of chunks: {len(chunks)}")
          
        
2 Embedding Generation
Each text chunk is converted into a numerical vector (embedding) using an embedding model. The choice of embedding model significantly impacts the quality of retrieval. Popular options include models from OpenAI, Sentence Transformers, and Cohere. The embeddings capture the semantic meaning of the text.
  • Embedding models (e.g., OpenAI's embeddings, Sentence Transformers)
  • API keys (for cloud-based embedding models)
  • Libraries for interacting with embedding models (e.g., openai, sentence-transformers)
          
from sentence_transformers import SentenceTransformer

# Load a pre-trained model (e.g., all-MiniLM-L6-v2)
model = SentenceTransformer('all-MiniLM-L6-v2')

def generate_embeddings(texts):
    embeddings = model.encode(texts)
    return embeddings

# Example usage:
embeddings = generate_embeddings(chunks)
print(f"Shape of the embeddings: {embeddings.shape}") # (number_of_chunks, embedding_dimension)
          
        
3 Vector Database Setup
Embeddings are stored in a vector database (also known as a vector store). This database allows for efficient similarity searches based on the embeddings. Popular choices include FAISS, Pinecone, ChromaDB, Weaviate, and Milvus. The choice depends on factors like scalability, performance requirements, and ease of use.
  • Vector database (e.g., FAISS, Pinecone, ChromaDB)
  • API keys/credentials (for cloud-based vector databases)
  • Libraries for interacting with the vector database (e.g., faiss-cpu, pinecone-client, chromadb)
          
import faiss
import numpy as np

# Assuming you have embeddings and chunks from previous steps

# Convert embeddings to numpy array if needed
embeddings_np = np.array(embeddings)

# Build the FAISS index (dimension of the embeddings)
dimension = embeddings_np.shape[1]
index = faiss.IndexFlatL2(dimension) # Using L2 distance for similarity

# Add the embeddings to the index
index.add(embeddings_np)

# (Optional) Save the index to disk
# faiss.write_index(index, "my_faiss_index.bin")

# Load the index
# index = faiss.read_index("my_faiss_index.bin")
          
        
4 Query Embedding and Similarity Search
When a user asks a question, the question is first converted into an embedding using the same embedding model used for the document chunks. The vector database is then queried to find the most similar embeddings (and their corresponding text chunks) to the query embedding. The similarity search often uses metrics like cosine similarity or Euclidean distance.
  • Embedding model (same as step 2)
  • Vector database query functionality
          
# Assuming you have the index and embedding model

def get_relevant_chunks(query, index, model, chunks, top_k=3):
    query_embedding = model.encode([query])
    query_embedding_np = np.array(query_embedding)

    # Perform the search
    distances, indices = index.search(query_embedding_np, top_k) # returns distances and indices of closest vectors

    relevant_chunks = [chunks[i] for i in indices[0]]
    return relevant_chunks

# Example Usage:
query = "What is the main topic of the document?"
relevant_chunks = get_relevant_chunks(query, index, model, chunks)
print(f"Relevant chunks:/n{relevant_chunks}")
          
        
5 Contextualization and Generation
The retrieved text chunks are combined with the user's query to create a context. This context is then fed into an LLM to generate a response. The LLM uses the context to answer the question, drawing upon the information retrieved from the document. Prompt engineering plays a crucial role in guiding the LLM.
  • Large Language Model (e.g., GPT-3.5, GPT-4, Llama 2)
  • API keys/credentials (for cloud-based LLMs)
  • Prompt engineering techniques
  • Libraries for interacting with LLMs (e.g., openai, transformers)
          
from langchain.llms import OpenAI
from langchain.prompts import PromptTemplate
from langchain.chains import LLMChain

# Replace with your OpenAI API key
import os
os.environ["OPENAI_API_KEY"] = "YOUR_OPENAI_API_KEY"

# Define the prompt template
template = """
You are a helpful assistant. Answer the question based on the context provided below.
Context:
{context}

Question: {question}

Answer:
"""
prompt = PromptTemplate(template=template, input_variables=["context", "question"])

# Initialize the LLM (e.g., OpenAI's GPT-3.5)
llm = OpenAI(model_name="gpt-3.5-turbo")

# Create the LLM chain
def generate_answer(question, relevant_chunks, llm, prompt):
    context = "/n".join(relevant_chunks)
    llm_chain = LLMChain(prompt=prompt, llm=llm)
    answer = llm_chain.run(context=context, question=question)
    return answer

# Example usage
question = "What are the key findings of the document?"
answer = generate_answer(question, relevant_chunks, llm, prompt)
print(f"Answer: {answer}")
          
        
6 Evaluation and Refinement
The performance of the RAG pipeline should be evaluated. Metrics to consider include the accuracy, relevance, and coherence of the generated responses. Based on the evaluation, you can refine the various components of the pipeline, such as the chunking strategy, the embedding model, the vector database configuration, and the prompt engineering. This is an iterative process.
  • Evaluation metrics (e.g., accuracy, relevance, coherence scores)
  • Human evaluation
  • Tools for automated evaluation (e.g., RAGAS, RAGatouille)
          
# Examples of evaluation
# 1. Human evaluation: Have human evaluators assess the generated answers.

# 2. Automated evaluation (e.g., using RAGAS)

# 3. Consider using metrics to evaluate the quality of the context returned

# 4. Analyze the results and iterate on your RAG pipeline.
          
        

Choosing the Right Tools and Models

The selection of tools and models is critical. Consider factors such as:

  • Data Volume and Complexity: For large datasets, choose a vector database that can scale.
  • Performance Requirements: Consider the latency requirements. Some vector databases are optimized for speed.
  • Cost: Cloud-based services have costs associated with them. Open-source options might be more cost-effective.
  • Ease of Use and Maintenance: Consider the learning curve and the effort required to maintain the system.
  • Embedding Model Accuracy: Experiment with different embedding models to find the one that performs best on your specific data and task.

The choice of the LLM also impacts the output quality. Experiment with different LLMs and prompt engineering techniques.

Advanced Techniques and Considerations

  • HyDE (Hypothetical Document Embeddings): Generate a hypothetical answer to the query and use the embedding of the hypothetical answer to retrieve relevant documents.
  • Query Transformation: Rewrite the user's query to improve retrieval accuracy.
  • Multi-Stage Retrieval: Implement multiple stages of retrieval, filtering documents based on different criteria.
  • Metadata Filtering: Use metadata associated with the document chunks to filter the retrieved results (e.g., date, author, source).
  • Handling Long Contexts: Use strategies like recursive summarization or long context window models to handle documents exceeding the context