PyRigi

PyRigi is a Python package for research in rigidity and flexibility of bar-and-joint frameworks. We aim at providing a tool for investigating combinatorial and geometric questions such as infinitesimal, global, minimal, or generic rigidity.

We use NetworkX for graph theory and SymPy for symbolic and numerical computations. We acknowledge these and all the other open-source projects upon which PyRigi is based.

Installation and usage

We have not reached a stable version yet, but the latest version requiring at least Python 3.10 can be installed by

pip install pyrigi

Then it can be used by

from pyrigi import Graph, Framework

Alternatively, one can clone/download the package from this GitHub repository.

Documentation

The documentation of the main branch is available online. For compiling it locally, see the development guide.

An important part of the documentation is the mathematical background. We specify the outputs of the methods in the package by providing rigorous mathematical definitions.

Questions and feature requests

We have a Zulip chat, where you can ask questions or propose new functionality. If you want to get access to it, please send an email to this address. You can also use the GitHub Discussions.

To report bugs or ask for new features, please create an issue.

Contributing

We appreciate contributions! Do you have a research result about rigidity or flexibility of bar-joint frameworks that could be implemented? Let us know! Or even better, implement it and contribute to the package!

Besides coding, you can also help for instance by extending the mathematical documentation or creating tutorials.

If you want to contribute, please, read the development guide and contact us.

License

The package is licensed under the MIT license.

The PyRigi Developers

The current maintainers of the project are:

Matteo Gallet
Georg Grasegger
Matthias Himmelmann
Jan Legerský

The decision to create PyRigi was made by the participants of the workshop Code of Rigidity (March 11–15, 2024), which was part of the Special Semester on Rigidity and Flexibility at RICAM, Linz, Austria.

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