Introduction

LlamaIndex (GPT Index) serves as an interface to connect Large Language Models (LLMs) with external data, utilizing various data structures like list index, vector index, keyword index, and tree index. It offers both high-level and low-level APIs to facilitate the creation of a Question-Answering (QA) system, with the high-level API enabling a quick setup and the low-level API allowing for customization. The process of evaluating retrieval-augmented generation can be challenging, but LlamaIndex provides modules for Question Generation and label-free Evaluation to address this. The evaluation process involves generating questions from documents, producing answers and source nodes using LlamaIndex QueryEngine abstractions, and assessing the alignment of responses, source nodes, and queries. This approach helps measure potential hallucinations in the model's responses by verifying if they are rooted in the provided context, thus enhancing the system's accuracy and reliability for production environments.