README.md

# AnalyticSDF

**Automatic Diagram Generation for Analytic Geometry Problems using Signed Distance Fields**

<p align="center">
  <img src="results/test/ellipse/problem_2063.png" width="600" alt="Example Output">
</p>

<p align="center">
  <img src="https://img.shields.io/badge/Python-3.9%2B-blue.svg" alt="Python">
  <img src="https://img.shields.io/badge/PyTorch-2.0%2B-ee4c2c.svg" alt="PyTorch">
  <img src="https://img.shields.io/badge/Accuracy-96.7%25-brightgreen.svg" alt="Accuracy">
  <img src="https://img.shields.io/badge/Problems-10,861-orange.svg" alt="Problems">
  <img src="https://img.shields.io/badge/License-MIT-green.svg" alt="License">
</p>

---

## Introduction

**AnalyticSDF** is an automatic system that converts mathematical geometry problem text into accurate visualizations. By leveraging **Signed Distance Fields (SDF)** combined with differentiable optimization, the system can automatically generate precise conic section diagrams from symbolic geometric expressions.

Traditional geometry diagram generation often relies on manual drawing or rule-based methods. This system takes a different approach: it models geometric constraints as differentiable loss functions and uses gradient-based optimization to find curve parameters that satisfy all constraints, ultimately rendering high-quality geometric diagrams.

### Key Features

- **Fully Automated**: Generate PNG diagrams directly from JSON-formatted geometry problems without manual intervention
- **High Accuracy**: Achieves **96.7%** validation pass rate on parseable problems
- **Large-Scale Validation**: Tested on **10,861** geometry problems across 3 datasets
- **Rigorous Verification**: Multi-dimensional geometric property validation including focus position, eccentricity, and asymptote slope

---

## Supported Curve Types

The system supports four classical conic sections, each with complete SDF representation and constraint validation:

| Curve Type | Standard Form | Validated Properties |
|------------|---------------|---------------------|
| **Ellipse** | x²/a² + y²/b² = 1 | Focus distance c²=a²-b², eccentricity, points on curve |
| **Hyperbola** | x²/a² - y²/b² = 1 | Focus distance c²=a²+b², asymptote slope, eccentricity |
| **Parabola** | y² = 4px | Focus position, directrix equation, points on curve |
| **Circle** | (x-h)² + (y-k)² = r² | Center position, radius, points on curve |

---

## How It Works

The system follows a four-stage pipeline:

```
Text Parsing → SDF Construction → Constraint Optimization → Diagram Rendering
```

### 1. Text Parsing

Extract geometric parameters from mathematical expressions. For example:

```
Input:  "ellipse x²/4 + y²/9 = 1"
Output: Ellipse(a=2, b=3, center=(0,0))
```

The parser supports various expression formats including fractions, radicals, and LaTeX-formatted mathematical expressions.

### 2. SDF Construction

Build a signed distance field function for each curve type. The SDF value represents the signed distance from any point in space to the curve boundary:
- Positive: point is outside the curve
- Negative: point is inside the curve
- Zero: point is exactly on the curve

### 3. Constraint Optimization

Optimize curve parameters via gradient descent to satisfy all geometric constraints:

```python
# Total loss = point constraint + focus constraint + eccentricity constraint + crowd penalty
L_total = λ₁·L_point + λ₂·L_focus + λ₃·L_ecc + λ₄·L_crowd
```

Using the AdamW optimizer, convergence typically occurs within 100-200 iterations.

### 4. Diagram Rendering

Extract the zero-level set of the SDF (i.e., the curve itself) and render in Chinese Gaokao (高考) analytic geometry style: white background, black curves, arrow axes through origin with O/x/y labels, feature point annotations (foci, vertices), and auxiliary elements (asymptotes, directrix) as dashed lines. No problem text, grid, or legend is included in the output.

---

## Datasets and Results

The system has been fully tested on three datasets:

| Dataset | Total Problems | Parseable | Successful | Parseable Accuracy |
|---------|----------------|-----------|------------|-------------------|
| dev | 1,035 | 809 | 788 | **97.4%** |
| test | 2,069 | 1,649 | 1,596 | **96.8%** |
| train | 7,757 | 6,052 | 5,849 | **96.6%** |
| **Total** | **10,861** | **8,510** | **8,233** | **96.7%** |

> **Note**: "Parseable" refers to problems with explicit geometric expressions (e.g., x²/4 + y²/9 = 1) rather than implicit or parametric forms. Approximately 22% of problems cannot be parsed due to overly complex or incomplete expressions.

### Curve Type Distribution

| Type | Dev | Test | Train | Total |
|------|-----|------|-------|-------|
| Ellipse | 220 | 467 | 1,734 | 2,421 |
| Hyperbola | 293 | 565 | 2,025 | 2,883 |
| Parabola | 262 | 532 | 2,000 | 2,794 |
| Circle | 13 | 32 | 90 | 135 |

---

## Installation and Usage

### Requirements

- Python >= 3.9
- PyTorch >= 2.0.0
- NumPy >= 1.24.0
- Matplotlib >= 3.7.0
- tqdm >= 4.65.0

### Install Dependencies

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

### Running Examples

```bash
# Process test dataset
python src/main.py --input data/test_en.json --output results/test/

# Process dev dataset
python src/main.py --input data/dev_en.json --output results/dev/

# Process train dataset (~30 minutes)
python src/main.py --input data/train_en.json --output results/train/

# Process only first 100 problems with verbose output
python src/main.py -i data/test_en.json -o results/test/ -m 100 -v
```

### Command Line Arguments

| Argument | Description | Default |
|----------|-------------|---------|
| `-i, --input` | Input JSON file path | `data/test_en.json` |
| `-o, --output` | Output directory | `results/` |
| `-m, --max` | Maximum number of problems to process | All |
| `-v, --verbose` | Enable verbose output | False |

### Python API

```python
from src.sdf_geo import SDFBatchProcessor

# Create processor
processor = SDFBatchProcessor(output_dir='results/')

# Batch processing
results = processor.process_batch('data/test_en.json', max_problems=100)

# Calculate success rate
success_rate = sum(r['success'] for r in results) / len(results)
print(f"Success rate: {success_rate:.1%}")
```

---

## Project Structure

```
Image_SDF/
├── data/
│   ├── dev_en.json          # Dev set (1,035 problems)
│   ├── test_en.json         # Test set (2,069 problems)
│   └── train_en.json        # Train set (7,757 problems)
├── results/
│   ├── dev/                 # Dev set results
│   ├── test/                # Test set results
│   └── train/               # Train set results
├── samples/                 # Sample images (3 per curve type per dataset)
├── src/
│   ├── main.py              # CLI entry point
│   └── sdf_geo/             # Core modules
│       ├── primitives.py    # SDF geometric primitives
│       ├── constraints.py   # Differentiable constraint functions
│       ├── parser.py        # Expression parser
│       ├── optimizer.py     # Gradient optimizer
│       ├── processor.py     # Batch processing, validation & visualization
│       └── renderer.py      # SDF field evaluation & curve rendering
├── create_samples.py        # Generate sample images from results
├── requirements.txt
└── README.md
```

---

## Output Format

Each problem generates a PNG image in Chinese Gaokao (高考) analytic geometry style, containing:

- **Geometric Curve**: Black curve rendered from the SDF zero-level set on white background
- **Feature Point Annotations**: Foci (F₁, F₂), vertices, center, marked as small black dots with labels
- **Coordinate System**: Arrow axes through origin with O, x, y labels (no grid)
- **Auxiliary Elements**: Asymptotes and directrix rendered as dashed lines

Results are organized by curve type:

```
results/test/
├── summary.json        # Statistics summary
├── circle/             # Circle diagrams
├── ellipse/            # Ellipse diagrams
├── hyperbola/          # Hyperbola diagrams
└── parabola/           # Parabola diagrams
```

---

## Validation Standards

The system employs multi-dimensional geometric property validation to ensure mathematical correctness of generated diagrams:

| Validation Item | Tolerance | Description |
|-----------------|-----------|-------------|
| Point on curve | 0.03 | SDF(p) ≈ 0 |
| Eccentricity | 0.05 | \|e_calculated - e_target\| < tol |
| Focus position | 0.05 | \|c_calculated - c_given\| < tol |
| Asymptote slope | 0.05 | \|b/a - slope\| < tol |

---

## Methodology

This implementation is based on the methodology described in:

> **GeoSDF: Plane Geometry Diagram Synthesis via Signed Distance Field**  

The core ideas of using signed distance fields for geometric representation and differentiable optimization for constraint satisfaction are derived from this work.

---

## License

MIT License