passagemath-cmr

========================================================================== passagemath: Combinatorial matrix recognition

passagemath <https://github.com/passagemath/passagemath>__ is open source mathematical software in Python, released under the GNU General Public Licence GPLv2+.

It is a fork of SageMath <https://www.sagemath.org/>__, which has been developed 2005-2025 under the motto “Creating a Viable Open Source Alternative to Magma, Maple, Mathematica, and MATLAB”.

The passagemath fork was created in October 2024 with the following goals:

• providing modularized installation with pip, thus completing a major project started in 2020 in the Sage codebase <https://github.com/sagemath/sage/issues/29705>__,
• establishing first-class membership in the scientific Python ecosystem,
• giving clear attribution of upstream projects <https://groups.google.com/g/sage-devel/c/6HO1HEtL1Fs/m/G002rPGpAAAJ>__,
• providing independently usable Python interfaces to upstream libraries,
• providing platform portability and integration testing services <https://github.com/passagemath/passagemath/issues/704>__ to upstream projects,
• inviting collaborations with upstream projects,
• building a professional, respectful, inclusive community <https://groups.google.com/g/sage-devel/c/xBzaINHWwUQ>__,
• developing a port to Pyodide <https://pyodide.org/en/stable/>__ for serverless deployment with Javascript,
• developing a native Windows port.

Full documentation <https://doc.sagemath.org/html/en/index.html>__ is available online.

passagemath attempts to support all major Linux distributions and recent versions of macOS. Use on Windows currently requires the use of Windows Subsystem for Linux or virtualization.

Complete sets of binary wheels are provided on PyPI for Python versions 3.9.x-3.12.x. Python 3.13.x is also supported, but some third-party packages are still missing wheels, so compilation from source is triggered for those.

About this pip-installable distribution package

This pip-installable distribution passagemath-cmr is a small optional distribution for use with passagemath-modules <https://pypi.org/project/passagemath-modules/>_ and passagemath-graphs <https://pypi.org/project/passagemath-graphs/>_.

It provides a Cython interface to the CMR library <https://github.com/discopt/cmr>_, which implements recognition and decomposition algorithms for:

• Totally Unimodular Matrices
• Network Matrices
• Complementary Totally Unimodular Matrices
• (Strongly) Equimodular and Unimodular Matrices
• Regular Matroids
• Graphic / Cographic / Planar Matrices
• Series-Parallel Matroids

Examples

::

$ pipx run --pip-args="--prefer-binary" --spec "passagemath-cmr[test]" ipython

In [1]: from sage.all__sagemath_cmr import *

In [2]: from sage.matrix.matrix_cmr_sparse import Matrix_cmr_chr_sparse

In [3]: M = Matrix_cmr_chr_sparse(MatrixSpace(ZZ, 3, 3, sparse=True), [[1, 0, 1], [0, 1, 1], [1, 2, 3]]); M
Out[3]:
[1 0 1]
[0 1 1]
[1 2 3]

In [4]: M.is_unimodular()
Out[4]: True

In [5]: M.is_strongly_unimodular()
Out[5]: False

Development

::

$ git clone --origin passagemath https://github.com/passagemath/passagemath.git  # or use your fork
$ cd passagemath
passagemath $ ./bootstrap
passagemath $ source ./.homebrew-build-env         # on macOS when homebrew is in use
passagemath $ export PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/lib/wsl/lib  # on WSL
passagemath $ export PIP_CONSTRAINT="$(pwd)/constraints_cmr.txt"
passagemath $ echo "passagemath-categories @ file://$(pwd)/pkgs/sagemath-categories" >> constraints_cmr.txt
passagemath $ echo "passagemath-modules @ file://$(pwd)/pkgs/sagemath-modules" >> constraints_cmr.txt
passagemath $ python3 -m venv cmr-venv
passagemath $ source cmr-venv/bin/activate
(cmr-venv) passagemath $ pip install -v -e pkgs/sagemath-cmr        \
                                        -e pkgs/sagemath-modules    \
                                        -e pkgs/sagemath-categories

Modularized use::

(cmr-venv) passagemath $ pip install -v passagemath-repl
(cmr-venv) passagemath $ sage
... sage.all is not available ...
sage: from sage.all__sagemath_modules import *
sage: matroids.Uniform(3, 4)

In plain Python::

(cmr-venv) passagemath $ python3
>>> from sage.all__sagemath_modules import *
>>> matroids.Uniform(3, 4)

For full functionality of Sage::

(cmr-venv) passagemath $ pip install -v passagemath-standard
(cmr-venv) passagemath $ sage
sage: matroids.Uniform(3, 4)