CoinBackend has previously been available as part of the SageMath source tree,
from which it is built as an "optional extension" when the cbc Sage package is installed.
However, it has not been available in binary distributions.
The present standalone Python package sage-numerical-backends-coin has been created from the SageMath sources, version 9.0.beta10; the in-tree version of CoinBackend has been removed in Sage ticket https://trac.sagemath.org/ticket/28175. SageMath 9.1 and later makes the package available as an optional Sage package (SPKG).
The current version of this package can also be installed on top of various Sage installations using pip. (Your installation of Sage must be based on Python 3; if your SageMath is version 9.2 or newer, it is.)
CBC can either be installed using its Sage package using
$ sage -i cbc
or any of the methods explained at https://github.com/coin-or/Cbc .
This package finds the CBC installation by means of pkgconfig.
Install this package from PyPI using
$ sage -pip install sage-numerical-backends-coin
or from GitHub using
$ sage -pip install git+https://github.com/sagemath/sage-numerical-backends-coin
(See .github/workflows/build.yml for details about package prerequisites on various systems.)
After a successful installation, Sage will automatically make this new backend the default MIP solver.
To select the 'Coin' solver explicitly as the default MIP backend, additionally use the following command.
sage: default_mip_solver('Coin')
To make these settings permanent, add this command to your ~/.sage/init.sage file.
Note that this setting will not affect doctesting (sage -t) because this file is ignored in doctesting mode.
To run the (limited) testsuite of this package, use:
$ sage setup.py test
To run the Sage testsuite with the default MIP solver set to the backend provided by this package, use:
$ sage setup.py check_sage_testsuite
The doctests can also be invoked using tox:
$ tox -e local
$ tox -e local-sage_testsuite
If you have docker installed, more tests can be run:
$ tox -e docker-sage_binary-cbc_coinbrew
See tox.ini for the available options.