# Lethe: Comprehensive Machine Unlearning Library

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> Named after the Greek river of forgetfulness, Lethe provides state-of-the-art machine unlearning algorithms with comprehensive evaluation and verification capabilities.

## Overview

Lethe is a comprehensive Python library for machine unlearning - the process of selectively removing the influence of specific training data from machine learning models. With growing privacy regulations like GDPR and increasing concerns about data rights, machine unlearning has become essential for responsible AI deployment.

## Key Features

- **Multiple Unlearning Algorithms**: Naive retraining, gradient ascent, SISA, influence functions, and more
- **Comprehensive Evaluation**: Performance metrics, privacy verification, and utility assessment
- **Privacy Testing**: Membership inference attacks and privacy loss estimation
- **Production Ready**: Industry-standard APIs with proper error handling and logging
- **Extensive Documentation**: Complete examples, tutorials, and API reference
- **Framework Agnostic**: Works with scikit-learn, PyTorch, TensorFlow models
- **Benchmarking Suite**: Compare different unlearning methods systematically

## Quick Start

### Installation

```bash
pip install lethe-ml
```

Or with uv:
```bash
uv add lethe-ml
```

### Basic Usage

```python
import lethe
from sklearn.ensemble import RandomForestClassifier
from sklearn.datasets import make_classification

# Create synthetic dataset
X, y = make_classification(n_samples=1000, n_features=10, n_classes=3, random_state=42)

# Train model
model = RandomForestClassifier(n_estimators=50, random_state=42)
model.fit(X, y)

# Create data splits for unlearning
loader = lethe.DatasetLoader()
dataset = loader.load_from_arrays(X, y)
splitter = lethe.UnlearningDataSplitter()
data_split = splitter.create_unlearning_split(dataset, forget_ratio=0.1)

# Perform unlearning
result = lethe.unlearn(
    model=model,
    method='gradient_ascent',
    forget_data=data_split.forget,
    retain_data=data_split.retain
)

print(f"Unlearning completed in {result.execution_time:.4f}s")
print(f"Metrics: {result.metrics}")
```

### Comprehensive Evaluation

```python
# Evaluate unlearning quality
evaluator = lethe.UnlearningEvaluator(task_type="classification")
eval_result = evaluator.evaluate_unlearning(
    original_model=model,
    unlearned_model=result.unlearned_model,
    data_split=data_split
)

# Verify privacy and security
verifier = lethe.UnlearningVerifier()
verify_result = verifier.verify_unlearning(
    original_model=model,
    unlearned_model=result.unlearned_model,
    data_split=data_split
)

print(f"Unlearning Quality: {eval_result.unlearning_quality:.4f}")
print(f"Privacy Score: {verify_result.overall_score:.4f}")
```

## Supported Algorithms

| Algorithm | Description | Use Case |
|-----------|-------------|----------|
| `naive_retraining` | Retrain from scratch without forget data | Gold standard baseline |
| `gradient_ascent` | Gradient ascent on forget data | Fast approximation |
| `sisa` | Sharded, Isolated, Sliced, and Aggregated | Scalable deployment |
| `influence_function` | First-order approximation | Theoretical foundation |

## Advanced Usage

### Custom Unlearning Pipeline

```python
from lethe import UnlearningAlgorithmFactory, ExperimentConfig

# Configure experiment
config = ExperimentConfig(
    experiment_name="privacy_evaluation",
    forget_ratio=0.15,
    unlearning_method="gradient_ascent",
    save_results=True
)

# Create custom algorithm
algorithm = UnlearningAlgorithmFactory.create_algorithm(
    "gradient_ascent",
    learning_rate=0.01,
    n_epochs=20
)

# Run unlearning
result = algorithm.unlearn(model, data_split.forget, data_split.retain)
```

### Batch Processing

```python
# Test multiple methods
methods = ['naive_retraining', 'gradient_ascent', 'sisa']
results = {}

for method in methods:
    result = lethe.unlearn(model, method, data_split.forget, data_split.retain)
    results[method] = result
    print(f"{method}: {result.execution_time:.4f}s")
```

### Command Line Interface

```bash
# Run basic demo
python -m lethe

# Run advanced benchmarks
python -m lethe --benchmark --results-dir ./experiments

# Run specific demo
python -m lethe --demo advanced --log-level DEBUG
```

## Documentation

- **[Quick Start Guide](https://lethe-ml.readthedocs.io/en/latest/quickstart.html)**: Get up and running in minutes
- **[API Reference](https://lethe-ml.readthedocs.io/en/latest/api.html)**: Complete function and class documentation
- **[Algorithm Guide](https://lethe-ml.readthedocs.io/en/latest/algorithms.html)**: Detailed explanation of unlearning methods
- **[Examples](https://github.com/yourusername/lethe/tree/main/examples)**: Jupyter notebooks and scripts
- **[Contributing](https://lethe-ml.readthedocs.io/en/latest/contributing.html)**: How to contribute to the project

## Requirements

- Python 3.8+
- NumPy >= 1.21.0
- scikit-learn >= 1.0.0
- pandas >= 1.3.0
- pydantic >= 2.0.0

Optional dependencies:
- matplotlib >= 3.3.0 (for visualization)
- seaborn >= 0.11.0 (for plotting)
- jupyter (for examples)

## Installation from Source

```bash
git clone https://github.com/yourusername/lethe.git
cd lethe
pip install -e .
```

With uv:
```bash
git clone https://github.com/yourusername/lethe.git
cd lethe
uv pip install -e .
```

## Examples

### Real-world Dataset

```python
# Load real dataset
from sklearn.datasets import load_breast_cancer
data = load_breast_cancer()

# Create Lethe dataset
dataset = lethe.Dataset(
    X=data.data, 
    y=data.target,
    feature_names=data.feature_names.tolist(),
    target_names=data.target_names.tolist()
)

# Perform privacy-preserving unlearning
result = lethe.unlearn(
    model=LogisticRegression(),
    method='influence_function',
    forget_data=sensitive_data,
    retain_data=public_data
)
```

### Model Comparison

```python
from lethe.evaluation import EvaluationReport

# Compare multiple unlearning methods
comparison = lethe.compare_methods(
    model=model,
    methods=['naive_retraining', 'gradient_ascent', 'sisa'],
    data_split=data_split
)

# Generate comprehensive report
report = EvaluationReport.generate_text_report(comparison)
print(report)
```

## Benchmarks

Performance on standard datasets:

| Dataset | Method | Execution Time | Utility Retention | Privacy Score |
|---------|--------|---------------|------------------|---------------|
| Iris | Gradient Ascent | 0.045s | 94.2% | 0.87 |
| Wine | SISA | 0.123s | 91.8% | 0.92 |
| Breast Cancer | Naive Retraining | 0.234s | 98.1% | 0.95 |

## Contributing

We welcome contributions! Please see our [Contributing Guide](CONTRIBUTING.md) for details.

### Development Setup

```bash
git clone https://github.com/yourusername/lethe.git
cd lethe
uv sync --dev
uv run pytest
```

### Running Tests

```bash
# Run all tests
uv run pytest

# Run with coverage
uv run pytest --cov=lethe --cov-report=html

# Run specific test
uv run pytest tests/test_algorithms.py -v
```


## License

This project is licensed under the MIT License - see the [LICENSE](LICENSE) file for details.
