Building RAG-based LLM Applications: A Comprehensive Guide

Building RAG-based LLM Applications: A Comprehensive Guide

The process of creating or building a highly performant, scalable, and cost-effective Retrieval Augmented Generation (RAG) based Large Language Model (LLM) application that leverages large language models (LLMs) to generate high-quality responses to user queries.

Build Retrieval Augmented Generation (RAG) Based applications using this Comprehensive Guide with Complete Steps Codes, and Comprehensive Information

Building a Retrieval Augmented Generation (RAG) based Large Language Model (LLM) application involves several steps:

1. Develop a RAG-based LLM application from scratch: This involves creating a model that can retrieve and generate responses based on the retrieved information.

Develop a RAG-based LLM application from scratch:

Utilize a transformer-based model like BERT or GPT for your language model.

For RAG (Retrieval-Augmented Generation), use a retriever model (e.g., DPR) to retrieve relevant documents and then use the language model to generate responses.

Implement an API to take user queries and return model-generated responses.

Example (using Hugging Face's Transformers library):


# Install necessary libraries
pip install transformers

# Implement a basic RAG-based LLM
from transformers import RagTokenizer, RagRetriever, RagModel

tokenizer = RagTokenizer.from_pretrained("facebook/rag-token-base")
retriever = RagRetriever.from_pretrained("facebook/rag-token-base")
model = RagModel.from_pretrained("facebook/rag-token-base")

# Implement function to generate response
def generate_response(query):
    input_ids = tokenizer(query, return_tensors="pt")["input_ids"]
    docs = retriever(query)
    outputs = model(input_ids, docs["input_ids"])
    response = tokenizer.batch_decode(outputs["output"], skip_special_tokens=True)
    return response[0]

# Example usage
user_query = "Tell me about artificial intelligence"
response = generate_response(user_query)

2. Scale the major workloads across multiple workers with different compute resources: This includes tasks such as loading, grouping, representing, indexing, and serving.

Scale major workloads across multiple workers:

Use a distributed computing framework like Apache Spark or Dask to parallelize and distribute tasks.

Deploy your application on a cloud platform and configure load balancing.

Pass the query to the embedding model:

Use a pre-trained embedding model like Word2Vec or FastText.

3. Pass the query to the embedding model: This is done to semantically represent it as an embedded query vector.

Pass the query through the model to get an embedded vector.

Example (using Gensim for Word2Vec):


from gensim.models import Word2Vec

# Train or load a Word2Vec model
model = Word2Vec(sentences, vector_size=100, window=5, min_count=1, workers=4)

# Embed a query
query_embedding = model.wv['your_query']

4. Pass the embedded query vector to our vector database: This allows us to retrieve the top-k relevant contexts, which are measured by the distance between the query embedding and the embedded chunks in our knowledge base.

Pass the embedded query vector to our vector database:

Use a vector database like Faiss or Annoy to efficiently retrieve similar vectors.

Example (using Faiss):


import faiss

# Index the embedded vectors
index = faiss.IndexFlatL2(embedding_size)

# Query the index
D, I =, k=top_k)

5. Pass the query text and the retrieved context text to the LLM: The LLM will generate a response using the provided content.

Use the RAG-based LLM from step 1.

Example: See step 1.

6. Evaluate different configurations of our application: This helps to optimize for both per-component (e.g., retrieval_score) and overall performance (e.g., quality_score).

Design a routing algorithm that dynamically decides whether to route a query to an open-source model or a closed LLM based on factors like cost and performance.

7. Implement a hybrid agent routing approach: This is done between open-source software and closed LLMs to create the most performant and cost-effective application.

Implement a hybrid agent routing approach:

Routing logic: Develop logic to route queries to appropriate agents based on criteria like complexity or cost.

8. Serve the application in a scalable and available manner: This ensures that the application can handle a large number of requests.

Serve the application in a scalable and available manner:

Deploy your application on a container orchestration platform like Kubernetes.

Use auto-scaling to handle varying loads.

Employ redundant services and load balancing for high availability.

9. Learn how various methods like fine-tuning, prompt engineering, lexical search, reranking, data flywheel, etc. impact our application’s performance: This helps to improve the application over time.

Learn how various methods impact the application’s performance:

Set up experiments to test different configurations and methods.

Collect and analyze performance metrics.

Iterate on your models and configurations based on the results.

Note: The examples provided are simplified and may need adjustments based on your specific requirements and the libraries/frameworks you are using.

Remember, building things from scratch helps you understand the pieces better. Once you do, using a library makes more sense.

Build Retrieval Augmented Generation (RAG) Based applications using this Comprehensive Guide with Complete Steps Codes, and Comprehensive Information

Breakdown of its key objectives:

1. Enhanced Performance and Scalability:

Load Distribution: Distributing major workloads across multiple workers with different compute resources ensures efficient handling of tasks like data loading, processing, and serving, preventing bottlenecks and optimizing resource utilization.

Hybrid Agent Routing: Strategically combining open-source software and closed LLMs strikes a balance between performance and cost, providing flexibility in model selection based on specific needs and constraints.

Scalable Architecture: Serving the application in a highly scalable and available manner guarantees its ability to handle large volumes of requests without compromising performance or uptime.

2. Optimized Knowledge Retrieval:

Semantic Query Representation: Transforming queries into embedded query vectors using an embedding model enables meaningful comparison with stored knowledge, ensuring accurate retrieval of relevant information.

Vector Database: Using a vector database for efficient retrieval of top-k relevant contexts based on query embedding similarity promotes accurate and context-aware responses.

3. High-Quality Response Generation:

Contextual Response Generation: LLM leverages both the query text and retrieved-context to generate more comprehensive and contextually relevant responses.

4. Continuous Improvement:

Systematic Evaluation: Evaluating different configurations optimizes performance at both component and system levels, identifying areas for improvement and fine-tuning.

Advanced Techniques: Exploration of methods like fine-tuning, prompt engineering, lexical search, reranking, and data flywheels enables ongoing refinement of the application's effectiveness.

5. Deeper Understanding Through Building:

Hands-on Learning: The process emphasizes the value of building components from scratch to gain a deeper understanding of their interactions and nuances, fostering informed decisions about when to leverage external libraries.

In essence, this process aims to construct a robust and efficient LLM-powered application capable of delivering accurate, informative, and context-aware responses to user queries, while emphasizing continuous optimization and learning for ongoing improvement.

[Also Read: Zoho LLM: India’s AI Challenge to ChatGPT and Google]

RAG-based LLM Applications Limitations And Mitigation Strategies

Limitations of RAG-based LLM Applications

Information Capacity: Base LLMs are only aware of the information they’ve been trained on and will fall short when required to know information beyond that.

Processing Speed: The generative LLMs have to process the content in a sequence. The longer the input, the slower the processing speed.

Reasoning Power: RAG applications are often topped with a generative LLM, which gives users the impression that the RAG application must have high-level reasoning ability. However, because the LLM has inadequate input compared to the perfect model, in the same way, the RAG applications don’t have the same level of reasoning power.

Mitigation Strategies for RAG-based LLM Applications

Fine-tuning and Prompt Engineering: Methods like fine-tuning, prompt engineering, lexical search, reranking, data flywheel, etc. can impact the application’s performance. Fine-tuning customizes a pre-trained LLM for a specific domain by updating most or all of its parameters with a domain-specific dataset.

Scaling: Major workloads (load, chunk, embed, index, serve, etc.) can be scaled across multiple workers with different compute resources.

Security Controls: The lack of security controls in RAG-based LLM applications can pose risks if not addressed properly. Understanding the security implications of RAG and implementing appropriate controls can help harness the power of LLMs while safeguarding against potential vulnerabilities.

These strategies can help overcome the limitations and enhance the performance of RAG-based LLM applications. However, it’s important to note that the effectiveness of these strategies can vary depending on the use case and implementation. It’s always recommended to evaluate different configurations of the application to optimize for both per-component and overall performance.

RAG-based LLM Applications Examples And Their Use Cases:

Here are some examples of RAG-based LLM applications and their use cases:

1. Question Answering Systems: One of the most common applications of RAG-based LLMs is in building question-answering systems. These systems can answer questions based on a specific external knowledge corpus. For instance, AWS demonstrated a solution to improve the quality of answers in such use cases over traditional RAG systems by introducing an interactive clarification component using LangChain. The system engages in a conversational dialogue with the user when the initial question is unclear, asks clarifying questions, and incorporates the new contextual information to provide an accurate, helpful answer.

2. Chatbots: Incorporating LLMs with chatbots allows the chatbots to automatically derive more accurate answers from company documents and knowledge bases. This can significantly improve the efficiency and effectiveness of customer service operations.

3. Documentation Assistant: Anyscale built a RAG-based LLM application that can answer questions about Ray, a Python framework for productionizing and scaling ML workloads. The goal was to make it easier for developers to adopt Ray and to help improve the Ray documentation itself.

These examples illustrate how RAG-based LLMs can be used to build intelligent systems that can interact with users in a more meaningful and context-aware manner. They extend the utility of LLMs to specific data sources, thereby augmenting the LLM’s capabilities.

FAQs On Rag Applications And Rag-Based Applications:

What are rag applications?

RAG stands for Retrieval-Augmented Generation. It's a technique that combines the strengths of two AI approaches:

Information retrieval: This part finds relevant information from specific sources, like your company's documents, databases, or even real-time feeds. Think of it as a super-fast and accurate librarian.

Text generation: This is where the LLM comes in. It takes the retrieved information and uses its language skills to generate informative, comprehensive, and even creative responses, tailored to the specific context.

What is the rag approach in LLM?

Think of RAG as a two-step process:

The librarian (information retrieval) gathers relevant materials.

The writer (text generation) uses those materials to craft a custom response.

The result? LLMs that are smarter, more accurate, and more helpful than ever before.

How do you implement a rag for an LLM?

Implementing RAG for an LLM involves setting up a system that:

Identifies the LLM's task or question.

Searches relevant data sources for related information.

Provides the retrieved information to the LLM as additional context.

The LLM then uses this context to generate its response.

This might involve building custom pipelines, choosing the right retrieval models, and fine-tuning the LLM for your specific data and tasks.

What are the benefits of RAG applications:

The benefits of RAG applications are:

More accurate and reliable responses: LLMs are less prone to hallucinations or factual errors when they have access to real-world data.

Improved domain-specific knowledge: RAG applications can be tailored to specific industries or fields, making LLMs true experts in their domains.

Personalized experiences: LLMs can access user data and preferences to generate highly personalized responses and recommendations.

Real-time insights: RAG applications can integrate with live data feeds, allowing LLMs to provide up-to-date information and analysis.

What are the practical applications of LLM?

The possibilities are limitless, but here are some examples:

Customer service chatbots: Imagine chatbots that can access your customer history and product information to provide personalized support and answer complex questions accurately.

Legal research assistants: LLMs can analyze legal documents, case law, and regulations to help lawyers research cases and prepare arguments more efficiently.

Medical diagnosis and treatment: LLMs can analyze patient data and medical literature to suggest diagnoses, treatment options, and even personalized care plans.

Financial analysis and reporting: LLMs can analyze market trends, company financials, and news to generate accurate reports and investment recommendations.

RAG applications are still evolving, but they represent a significant leap forward in LLM technology. By combining the power of information retrieval with the creativity and fluency of text generation, RAG is opening up a world of possibilities for businesses and individuals alike.


Finally, RAG-based LLM Applications have a long way to go for further refinement which is a continuous process for every individual till his or her requirement and satisfaction. Wishing You All A Happy RAG-based LLM Applications Time.

For Any Further Help For A Free POC, You May Get In Touch With Abacus AI As Per the Offer By Their CEO Ms. Bindu Reddy

Wishing You All A Happy RAG-based LLM Applications Building Time.

Additional Resources:

Abacus AI

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