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cbcpy

Native Python interface for Coin-or Branch and Cut Solver (Cbc).

Description

This project provide the build mechanism to automatically generate the wrapper code between Cbc C++ code and Python using SWIG.

This project was develop as part of the CBC Coin-or Sprint Aug 2019.

Binaries for the following platform are pre-compiled and available on pypi.

  • linux x86_64 / python 2.7
  • linux x86_64 / python 3.5
  • linux x86_64 / python 3.6
  • linux x86_64 / python 3.7
  • win x86 / python 2.7
  • win x86 / python 3.5
  • win x86 / python 3.6
  • win x86 / python 3.7
  • win x86_64 / python 3.5
  • win x86_64 / python 3.6
  • win x86_64 / python 3.7

Linux x86 is not supported.

Installation

Pre-compiled python packages are deployed to cbcpy Pypi repositories. To install cbcpy you should make use of pip command line:

pip install cbcpy

The packages include pre-compiled version of Cbc.

For Windows: You must install Visual C++ Redistributable for VS2015

Usage

Here a minimalistic python script making use of cbcpy. You may download p0033.mps from here.

import cbcpy as cbc
solver1 = cbc.OsiClpSolverInterface()
solver1.readMps("p0033.mps")
model = cbc.CbcModel(solver1)
model.branchAndBound()
numberColumns = model.solver().getNumCols()
p_solution = model.solver().getColSolution()
solution = cbc.doubleArray_frompointer(p_solution)

for i in range(numberColumns):
  value = solution[i]
  print("%s has value %s" % (i, value))

Documentation

Original documentation from Cbc project is available in python using the help() function.

# python
Python 2.7.16 (default, Jul 13 2019, 16:01:51) 
[GCC 8.3.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import cbcpy
>>> help(cbcpy)
Help on module cbcpy:

Troubleshooting

The specified module could not be found.

>>> import cbcpy
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Python37-32\lib\site-packages\cbcpy.py", line 15, in <module>
    import _cbcpy
ImportError: DLL load failed: The specified module could not be found.

This error might occur on Windows platform when the file msvcp140.dll cannot be found. You must install Visual C++ Redistributable for VS2015. For 32-bit download "vc_redist.x86.exe" file and for 64-bit download "vc_redist.x64.exe" file.

Support

To get community help for cbcpy, you may send email to the Cbc mailing list.

You may also get paid support by contacting Patrik Dufresne Service Logiciel.