PageIndex/README.md

# PageIndex

### **Document Index System for Reasoning-Based RAG**

Traditional vector-based retrieval relies heavily on semantic similarity. But when working with professional documents that require domain expertise and multi-step reasoning, similarity search often falls short.

**Reasoning-Based RAG** offers a better alternative: enabling LLMs to *think* and *reason* their way to the most relevant document sections. Inspired by **AlphaGo**, we leverage **tree search** to perform structured document retrieval.

**PageIndex** is an indexing system that builds search trees from long documents, making them ready for reasoning-based RAG.

Built by [Vectify AI](https://vectify.ai/pageindex)

---

## 🔍 What is PageIndex?

**PageIndex** transforms lengthy PDF documents into a semantic **tree structure**, similar to a "table of contents" but optimized for use with Large Language Models (LLMs).
It’s ideal for: financial reports, regulatory filings, academic textbooks, legal or technical manuals or any document that exceeds LLM context limits.

### ✅ Key Features

- **Scales to Massive Documents**  
  Designed to handle hundreds or even thousands of pages with ease.
    
- **Hierarchical Tree Structure**  
  Enables LLMs to traverse documents logically—like an intelligent, LLM-optimized table of contents.

- **Precise Page Referencing**  
  Every node contains its own summary and start/end page physical index, allowing pinpoint retrieval.

- **Chunk-Free Segmentation**  
  No arbitrary chunking. Nodes follow the natural structure of the document.

---

## 📦 PageIndex Format

Here is an example output. See more [example documents](https://github.com/VectifyAI/PageIndex/tree/main/docs) and [generated trees](https://github.com/VectifyAI/PageIndex/tree/main/results).

```json
{
  "title": "Financial Stability",
  "node_id": "0006",
  "start_index": 21,
  "end_index": 22,
  "summary": "The Federal Reserve ...",
  "child_nodes": [
    {
      "title": "Monitoring Financial Vulnerabilities",
      "node_id": "0007",
      "start_index": 22,
      "end_index": 28,
      "summary": "The Federal Reserve's monitoring ..."
    },
    {
      "title": "Domestic and International Cooperation and Coordination",
      "node_id": "0008",
      "start_index": 28,
      "end_index": 31,
      "summary": "In 2023, the Federal Reserve collaborated ..."
    }
  ]
}

```
Notice: the node_id and summary generation function will be added soon.

## 🧠 Reasoning-Based RAG with PageIndex

Use PageIndex to build **reasoning-based retrieval systems** without relying on semantic similarity. Great for domain-specific tasks where nuance matters.

### 🛠️ Example Prompt

```python
prompt = f"""
You are given a question and a tree structure of a document.
You need to find all nodes that are likely to contain the answer.

Question: {question}

Document tree structure: {structure}

Reply in the following JSON format:
{{
  "thinking": <reasoning about where to look>,
  "node_list": [node_id1, node_id2, ...]
}}
"""
```

## 🚀 Usage

Follow these steps to generate a PageIndex tree from a PDF document.

### 1. Install dependencies

```bash
pip3 install -r requirements.txt
```

### 2. Set your OpenAI API key

Create a `.env` file in the root directory and add your API key:

```bash
CHATGPT_API_KEY=your_openai_key_here
```

### 3. Run PageIndex on your PDF

```bash
python3 page_index.py --pdf_path /path/to/your/document.pdf
```

The results will be saved in the `./results/` directory.

## 🛤 Roadmap

- [ ]  Add node summary and document selection
- [ ]  Technical report on PageIndex design
- [ ]  Efficient tree search algorithms for large documents
- [ ]  Integration with vector-based semantic retrieval

## 📈 Case Study: Mafin 2.5

[Mafin 2.5](https://vectify.ai/blog/Mafin2.5) is a state-of-the-art reasoning-based RAG model designed specifically for financial document analysis. Built on top of **PageIndex**, it achieved an impressive **98.7% accuracy** on the [FinanceBench](https://github.com/VectifyAI/Mafin2.5-FinanceBench) benchmark—significantly outperforming traditional vector-based RAG systems.

PageIndex’s hierarchical indexing enabled precise navigation and extraction of relevant content from complex financial reports, such as SEC filings and earnings disclosures.

👉 See full [benchmark results](https://github.com/VectifyAI/Mafin2.5-FinanceBench) for detailed comparisons and performance metrics.

## 📬 Contact Us

Need customized support for your documents or reasoning-based RAG system?

👉 [Contact us here](https://ii2abc2jejf.typeform.com/to/meB40zV0)