Empowering Contextual Document Retrieval: Leveraging GPT-2 and LlamaIndex

Aadya Singh 26 Sep, 2023 • 6 min read


In the world of information retrieval, where oceans of text data await exploration, the ability to pinpoint relevant documents efficiently is invaluable. Traditional keyword-based search has its limitations, especially when dealing with personal and confidential data. To overcome these challenges, we turn to the fusion of two remarkable tools:  leveraging GPT-2 and LlamaIndex, an open-source library designed to handle personal data securely. In this article, we’ll delve into the code that showcases how these two technologies combine forces to transform document retrieval.

 Leveraging GPT-2 and LlamaIndex

Learning Objectives

  • Learn how to effectively combine the power of GPT-2, a versatile language model, with LLAMAINDEX, a privacy-focused library, to transform document retrieval.
  • Gain insights into a simplified code implementation that demonstrates the process of indexing documents and ranking them based on similarity to a user query using GPT-2 embeddings.
  • Explore the future trends in document retrieval, including the integration of larger language models, support for multimodal content, and ethical considerations, and understand how these trends can shape the field.

This article was published as a part of the Data Science Blogathon.

GPT-2: Unveiling the Language Model Giant

Unmasking GPT-2

GPT-2 stands for “Generative Pre-trained Transformer 2,” and it’s the successor to the original GPT model. Developed by OpenAI, GPT-2 burst onto the scene with groundbreaking capabilities in understanding and generating human-like text. It boasts a remarkable architecture built upon the Transformer model, which has become the cornerstone of modern NLP.

The Transformer Architecture

The basis of GPT-2 is the Transformer architecture, a neural network design introduced by Ashish Vaswani et al. in the article “Let it be what you want it to be.” This model revolutionized NLP by increasing consistency, efficiency, and effectiveness. Transformer’s core features such as self-monitoring, spatial transformation, and multiheaded listening enable GPT-2 to understand content and relationships in text like never before.

Language model giant |  Leveraging GPT-2 and LlamaIndex
Transformer Architecture: https://proceedings.neurips.cc/paper/2017/file/3f5ee243547dee91fbd053c1c4a845aa-Paper.pdf

Multitask Learning

GPT-2 distinguishes itself through its remarkable prowess in multitask learning. Unlike models constrained to a single natural language processing (NLP) task, GPT-2 excels in a diverse array of them. Its capabilities encompass tasks such as text completion, translation, question-answering, and text generation, establishing it as a versatile and adaptable tool with broad applicability across various domains.

Code Breakdown: Privacy-Preserving Document Retrieval

Now, we will delve into a straightforward code implementation of LLAMAINDEX that leverages a GPT-2 model sourced from the Hugging Face Transformers library. In this illustrative example, we employ LLAMAINDEX to index a collection of documents containing product descriptions. These documents are then ranked based on their similarity to a user query, showcasing the secure and efficient retrieval of relevant information.

 Core features offered by LLM Image |  Leveraging GPT-2 and LlamaIndex
Source: https://www.aktagon.com/images/articles/LlamaIndex-core-concepts.jpg

NOTE: Import transformers if you have not already used: !pip install transformers

import torch
from transformers import GPT2Tokenizer, GPT2Model
from sklearn.metrics.pairwise import cosine_similarity

# Loading GPT2 model and its tokenizer
model_name = "gpt2"  
tokenizer = GPT2Tokenizer.from_pretrained(model_name)
tokenizer.pad_token = "[PAD]"  
model = GPT2Model.from_pretrained(model_name)

# Substitute with your documents
documents = [
    "Introducing our flagship smartphone, the XYZ Model X.",
    "This cutting-edge device is designed to redefine your mobile experience.",
    "With a 108MP camera, it captures stunning photos and videos in any lighting condition.",
    "The AI-powered processor ensures smooth multitasking and gaming performance. ",
    "The large AMOLED display delivers vibrant visuals, and the 5G connectivity offers blazing-fast internet speeds.",
    "Experience the future of mobile technology with the XYZ Model X.",

# Substitute with your query
query = "Could you provide detailed specifications and user reviews for the XYZ Model X smartphone, including its camera features and performance?"

# Creating embeddings for documents and query
def create_embeddings(texts):
    inputs = tokenizer(texts, return_tensors="pt", padding=True, truncation=True)
    with torch.no_grad():
        outputs = model(**inputs)
    embeddings = outputs.last_hidden_state.mean(dim=1).numpy()
    return embeddings

# Passing documents and query to create_embeddings function to create embeddings
document_embeddings = create_embeddings(documents)
query_embedding = create_embeddings(query)

# Reshape embeddings to 2D arrays
document_embeddings = document_embeddings.reshape(len(documents), -1)
query_embedding = query_embedding.reshape(1, -1)

# Calculate cosine similarities between query and documents
similarities = cosine_similarity(query_embedding, document_embeddings)[0]

# Rank and display the results
results = [(document, score) for document, score in zip(documents, similarities)]
results.sort(key=lambda x: x[1], reverse=True)

print("Search Results:")
for i, (result_doc, score) in enumerate(results, start=1):
    print(f"{i}. Document: {result_doc}\n   Similarity Score: {score:.4f}")
 Image of output search results: Author

Integration of Larger Language Models

The future promises the integration of even larger language models into document retrieval systems. Models surpassing the scale of GPT-2 are on the horizon, offering unparalleled language understanding and document comprehension. These giants will enable more precise and context-aware retrieval, enhancing the quality of search results.

Support for Multimodal Content

Document retrieval is no longer limited to text alone. The future holds the integration of multimodal content, encompassing text, images, audio, and video. Retrieval systems will need to adapt to handle these diverse data types, offering a richer user experience. Our code, with its focus on efficiency and optimization, paves the way for seamlessly integrating multimodal retrieval capabilities.

 Leveraging GPT-2 and LlamaIndex
Source: https://miro.medium.com/v2/resize:fit:1400/0*MuuoyaC-_rpQZ5r8.jpg

Ethical Considerations and Bias Mitigation

As document retrieval systems advance in complexity, ethical considerations emerge as a central focus. The imperative of achieving equitable and impartial retrieval outcomes becomes paramount. Future developments will concentrate on employing bias mitigation strategies, promoting transparency, and upholding responsible AI principles. The code we’ve examined lays the groundwork for constructing ethical retrieval systems that emphasize fairness and impartiality in information access.

4 stages of ethical AI |  Leveraging GPT-2 and LlamaIndex


In conclusion, the fusion of GPT-2 and LLAMAINDEX offers a promising avenue for enhancing document retrieval processes. This dynamic pairing has the potential to revolutionize the way we access and interact with textual information. From safeguarding privacy to delivering context-aware results, the collaborative power of these technologies opens doors to personalized recommendations and secure data retrieval. As we venture into the future, it is essential to embrace the evolving trends, such as larger language models, support for diverse media types, and ethical considerations, to ensure that document retrieval systems continue to evolve in harmony with the changing landscape of information access.

Key Takeaways

  • The article highlights leveraging GPT-2 and LLAMAINDEX, an open-source library designed for secure data handling. Understanding how these two technologies can work together is crucial for efficient and secure document retrieval.
  • The provided code implementation showcases how to use GPT-2 to create document embeddings and rank documents based on their similarity to a user query. Remember the key steps involved in this code to apply similar techniques to your own document retrieval tasks.
  • Stay informed about the evolving landscape of document retrieval. This includes the integration of even larger language models, support for processing multimodal content (text, images, audio, video), and the growing importance of ethical considerations and bias mitigation in retrieval systems.

Frequently Asked Questions

Q1: How does LLAMAINDEX handle multilingual content?

A1: LLAMAINDEX can be fine-tuned on multilingual data, enabling it to effectively index and search content in multiple languages.

Q2: Are there any open-source libraries available for implementing LLAMAINDEX?

A2: Yes, while LLAMAINDEX is relatively new, open-source libraries like Hugging Face Transformers can be adapted for this purpose.

Q3: Can LLAMAINDEX be used with audio or video content?

A3: Yes, LLAMAINDEX can be extended to process and index multimedia content by leveraging audio and video transcription and embedding techniques.

Q4: How does LLAMAINDEX handle privacy and data security?

A4: LLAMAINDEX can incorporate privacy-preserving techniques, such as federated learning, to protect user data and ensure data security.

Q5: What are the computational requirements for implementing LLAMAINDEX?

A5: Implementing LLAMAINDEX can be computationally intensive, requiring access to powerful GPUs or TPUs, but cloud-based solutions can help mitigate these resource constraints.


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Aadya Singh 26 Sep 2023

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