FDFI - Flow-Disentangled Feature Importance

A Python library for computing feature importance using disentangled methods, inspired by SHAP.

Current release: 0.0.2

Overview

FDFI (Flow-Disentangled Feature Importance) is a Python module that provides interpretable machine learning explanations through disentangled feature importance methods. This package implements both DFI (Disentangled Feature Importance) and FDFI (Flow-DFI) methods. Similar to SHAP, FDFI helps you understand which features are driving your model's predictions.

Features

• 🎯 Multiple Explainer Types: Tree, Linear, and Kernel explainers for different model types
• 🧭 OT-Based DFI: Gaussian OT (OTExplainer) and Entropic OT (EOTExplainer)
• 🌊 Flow-DFI: FlowExplainer with CPI and SCPI methods for non-Gaussian data
• 📊 Rich Visualizations: Summary, waterfall, force, and dependence plots
• 🔧 Easy to Use: Simple API similar to SHAP
• 🚀 Extensible: Built with modularity in mind for future enhancements

Installation

From Source

git clone https://github.com/jaydu1/FDFI.git
cd FDFI
pip install -e .

Dependencies

Use pyproject.toml extras:

pip install -e ".[dev]"
pip install -e ".[plots]"
pip install -e ".[flow]"

Quick Start

import numpy as np
from fdfi.explainers import OTExplainer

# Define your model
def model(X):
    return X.sum(axis=1)

# Create background data
X_background = np.random.randn(100, 10)

# Create an explainer
explainer = OTExplainer(model, data=X_background, nsamples=50)

# Explain test instances
X_test = np.random.randn(10, 10)
results = explainer(X_test)

# Confidence intervals (post-hoc)
ci = explainer.conf_int(alpha=0.05, target="X", alternative="two-sided")

CI Defaults in v0.0.2

By default, conf_int() now uses:

• var_floor_method="mixture"
• margin_method="mixture"

This improves stability for weak effects and avoids ad hoc thresholding in many use cases. You can still override both methods explicitly if needed.

EOT Options (Entropic OT)

EOTExplainer supports adaptive epsilon, stochastic transport sampling, and Gaussian/empirical targets:

from fdfi.explainers import EOTExplainer

explainer = EOTExplainer(
    model.predict,
    X_background,
    auto_epsilon=True,
    stochastic_transport=True,
    n_transport_samples=10,
    target="gaussian",  # or "empirical"
)
results = explainer(X_test)

Flow-DFI with FlowExplainer

FlowExplainer uses normalizing flows for non-Gaussian data, supporting both CPI (Conditional Permutation Importance) and SCPI (Sobol-CPI):

• CPI: Average predictions first, then squared difference: $(Y - E[f(\tilde{X})])^2$
• SCPI: Squared differences first, then average: $E[(Y - f(\tilde{X}_b))^2]$

from fdfi.explainers import FlowExplainer

# Create explainer with CPI (default)
explainer = FlowExplainer(
    model.predict,
    X_background,
    fit_flow=True,
    method='cpi',     # 'cpi', 'scpi', or 'both'
    num_steps=200,    # flow training steps
    nsamples=50,      # counterfactual samples
    sampling_method='resample',  # 'resample', 'permutation', 'normal', 'condperm'
)

results = explainer(X_test)
# results['phi_Z']: Z-space importance
# results['phi_X']: same as phi_Z (Z-space methods)

# Confidence intervals
ci = explainer.conf_int(alpha=0.05, target="Z", alternative="two-sided")

Explainer diagnostics (new in v0.0.2)

Disentangled explainers (OTExplainer, EOTExplainer, and FlowExplainer) report two diagnostics with qualitative labels (GOOD / MODERATE / POOR) using consistent [FDFI][DIAG] logging:

• Latent independence (median dCor) — lower is better (thresholds: <0.10 good, <0.25 moderate).
• Distribution fidelity (MMD) — lower is better (thresholds: <0.05 good, <0.15 moderate).

Example log:

[FDFI][DIAG] Flow Model Diagnostics
[FDFI][DIAG] Latent independence (median dCor): 0.0421 [GOOD]  → lower is better
[FDFI][DIAG] Distribution fidelity (MMD):       0.0187 [GOOD]  → lower is better

Access diagnostics directly:

diag = explainer.diagnostics
print(diag["latent_independence_median"], diag["latent_independence_label"])
print(diag["distribution_fidelity_mmd"], diag["distribution_fidelity_label"])

For advanced users, flow models can be trained separately:

from fdfi.models import FlowMatchingModel

# Train flow model externally
flow_model = FlowMatchingModel(X_background, dim=X_background.shape[1])
flow_model.fit(num_steps=500, verbose='final')

# Set pre-trained flow
explainer = FlowExplainer(model.predict, X_background, fit_flow=False)
explainer.set_flow(flow_model)

Project Structure

FDFI/
├── fdfi/                  # Main package directory
│   ├── __init__.py       # Package initialization
│   ├── explainers.py     # Explainer classes
│   ├── plots.py          # Visualization functions
│   └── utils.py          # Utility functions
├── tests/                 # Test suite
│   ├── test_explainers.py
│   ├── test_plots.py
│   └── test_utils.py
├── docs/                  # Documentation & tutorials
│   └── tutorials/        # Jupyter notebook tutorials
├── pyproject.toml        # Package configuration
└── README.md            # This file

Development Status

🚧 This is starter code for DFI development. The core structure and API are in place, but full implementations are coming soon.

Current status:

• ✅ Package structure established
• ✅ Base classes and interfaces defined
• ✅ Testing framework set up
• ✅ Documentation structure created
• 🚧 Core algorithms (in development)
• 🚧 Visualization functions (in development)

Testing

Run the test suite:

# Install development dependencies
pip install -e ".[dev]"

# Run tests
pytest

# Run tests with coverage
pytest --cov=fdfi --cov-report=html

Documentation

Full documentation and tutorials are available in the docs/ directory:

• Quickstart Tutorial
• OT Explainer Tutorial
• EOT Explainer Tutorial
• Flow Explainer Tutorial
• Confidence Intervals

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under the MIT License - see the LICENSE file for details.

References

FDFI is based on:

• Du, J.-H., Roeder, K., & Wasserman, L. (2025). Disentangled Feature Importance. arXiv preprint arXiv:2507.00260.
• Chen, X., Guo, Y., & Du, J.-H. (2026). Flow-Disentangled Feature Importance. In The Thirteenth International Conference on Learning Representations (ICLR).

Related work:

• SHAP: A game theoretic approach to explain machine learning models

Citation

If you use DFI in your research, please cite:

@software{dfi2026,
  title={DFI: Python Library for Disentangled Feature Importance},
  author={DFI Team},
  year={2026},
  url={https://github.com/jaydu1/FDFI}
}

@article{du2025disentangled,
  title={Disentangled Feature Importance},
  author={Du, Jin-Hong and Roeder, Kathryn and Wasserman, Larry},
  journal={arXiv preprint arXiv:2507.00260},
  year={2025}
}

@inproceedings{chen2026flow,
  title={Flow-Disentangled Feature Importance},
  author={Chen, Xin and Guo, Yifan and Du, Jin-Hong},
  booktitle={The Thirteenth International Conference on Learning Representations},
  year={2026}
}

Contact

For questions and issues, please use the GitHub issue tracker.