libigl

libigl Python Bindings

This repository contains the source code for the python bindings for the C++ libigl library written using nanobind. Functions allow NumPy arrays as input and output for dense matrices and vectors and SciPy sparse matrices for sparse matrices.

Installation

python -m pip install libigl

Documentation

:warning: WARNING
The python-binding documentation is perennially out of date and will likely be removed/changed.

• A tutorial on how to use the bindings can be found here
• A function reference can be found here

Getting the current version of libigl within python code

Since version 2.5.4.dev0, the igl.__version__ attribute has been removed. To get the version of the libigl package you're using within your python code, you can use the following code:

import importlib.metadata
libigl_version = importlib.metadata.version('libigl')

The version of libigl is defined in the pyproject.toml file.

Compiling and modifying the bindiings

According to the scikit-build-core documentation, the way to make an editable (incremental) build is to:

• Preinstall the dependencies (at the top of pyproject.toml
• Then use this very long command:

CMAKE_BUILD_PARALLEL_LEVEL=10  python -m pip install --no-build-isolation --config-settings=editable.rebuild=true -Cbuild-dir=build -ve.

The CMAKE_BUILD_PARALLEL_LEVEL=10 will invoke with 10 parallel build threads.

Adding a missing binding

Bindings are fairly mechanical to write. For example, suppose we didn't have a binding for the c++ function igl::moments. The first step would be to look at the corresponding .h header file in the C++ libigl library: moments.h.

Then we would create the src/moments.cpp file in this project which uses Eigen::MatrixXN for numeric types and Eigen::MatrixXI for integer types. Typically this requires a simple wrapper around the function matching its signature to these types and some boilerplate void bind_moments(... code which adds the function to the python module.

Simply adding this .cpp file will be enough to add the bindings on the next build.

If submitting a pull request with a new binding, please also add an execution test in tests/test_all.py to ensure the binding can at least be called as expected.

Testing cibuildwheel locally

Install whichever version of Python from the official website and then run:

/Library/Frameworks/Python.framework/Versions/3.11/bin/python3.11 -m venv venv-official-3.11
source venv-official-3.11/bin/activate
python -m pip install cibuildwheel
CIBW_BUILD="cp311-*" python -m cibuildwheel --output-dir wheelhouse --platform macos

Downloading all the artifacts

A successful .github/workflows/wheels.yml run will a lot of .whl files. To download these all at once, you can use the following command:

mkdir wheelhouse
cd wheelhouse
gh run download [runid]

Then these can be uploaded to pypi using:

python -m twine upload --repository testpypi wheelhouse/*/*.whl wheelhouse/*/*.tar.gz

Acknowledgements

The original python bindings were generated and maintained by @teseoch, @KarlLeell, @fwilliams, @skoch9, and @danielepanozzo

The modern python bindings (since 2.5.4.dev0) can largely be blamed on @alecjacobson.