==========================================================================
 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 uses the motto "Creating a Free Passage Between the
Scientific Python Ecosystem and Mathematical Software Communities."
It was created in October 2024 with the following goals:

-  providing modularized installation with pip,
-  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,
-  offering `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>`__,
-  `empowering Sage users to participate in the scientific Python ecosystem
   <https://github.com/passagemath/passagemath/issues/248>`__ by publishing packages,
-  developing a port to `Pyodide <https://pyodide.org/en/stable/>`__ for
   serverless deployment with Javascript,
-  developing a native Windows port.

`Full documentation <https://passagemath.org/docs/latest/html/en/index.html>`__ is
available online.

passagemath attempts to support and provides binary wheels suitable for
all major Linux distributions and recent versions of macOS.

Binary wheels for native Windows (x86_64) are are available for a subset of
the passagemath distributions. Use of the full functionality of passagemath
on Windows currently requires the use of Windows Subsystem for Linux (WSL)
or virtualization.

The supported Python versions in the passagemath 10.6.x series are 3.10.x-3.14.x.


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 passagemath_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 $ export PIP_BUILD_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 passagemath_modules import *
    sage: matroids.Uniform(3, 4)
    U(3, 4): Matroid of rank 3 on 4 elements with circuit-closures
    {3: {{0, 1, 2, 3}}}

In plain Python::

    (cmr-venv) passagemath $ python3
    >>> from passagemath_modules import *
    >>> matroids.Uniform(3, 4)
    U(3, 4): Matroid of rank 3 on 4 elements with circuit-closures
    {3: {{0, 1, 2, 3}}}

For full functionality of Sage::

    (cmr-venv) passagemath $ pip install -v passagemath-standard
    (cmr-venv) passagemath $ sage
    sage: matroids.Uniform(3, 4)
    U(3, 4): Matroid of rank 3 on 4 elements with circuit-closures
    {3: {{0, 1, 2, 3}}}
