CBC#

The COIN Branch and Cut solver (CBC) is an open-source mixed-integer program (MIP) solver written in C++. The driver is built on the MP library, which reformulates logical and other expressions that the solver does not accept natively.

Learn More | Modeling guide | Features | Options | Changes

Download CBC

How to use it#

How to install using amplpy:

# Install Python API for AMPL:
$ python -m pip install amplpy --upgrade

# Install AMPL & solver modules:
$ python -m amplpy.modules install cbc # install CBC

# Activate your license (e.g., free ampl.com/ce or ampl.com/academia licenses):
$ python -m amplpy.modules activate <your-license-uuid>

How to use:

from amplpy import AMPL
ampl = AMPL()
...
ampl.solve(solver="cbc", cbc_options="option1=value1 option2=value2")

Learn more about what we have to offer to implement and deploy Optimization in Python.

AMPL APIs give access to AMPL from a programming language:

ampl: option solver cbc; # change the solver
ampl: option cbc_options 'option1=value1 option2=value2'; # specify options
ampl: solve; # solve the problem

Resources#

Features#

Problem types and algorithms#

Problem types

  • LP

  • MILP

Received natively: linear constraints and ranges, SOS. Quadratic objectives are not supported; nonlinear functions are approximated piecewise-linearly; logical constraints become big-M rows.

All constructs: native constraints and expressions by driver.

LP: CLP simplex and barrier

CBC solves LPs with CLP. Barrier settings: bar:... options.

MIP: branch-and-cut

Cut generators: cut:... options, e.g., cut:gomorycuts.

Instrumentation#

For a generic summary of the options and features used most often, see Important features in the MP documentation.

For all models

Model export

Option tech:writemodel. Details

Basis input and output

Option alg:basis. Details

Multiple objectives

Emulated by MP. Option obj:multi. Details

Warm start

Option alg:start. Details

Solver options#

Full list of solver options:

More details on solver options: MP solver options.

Retrieving solutions#

The outcome of the last optimization is stored in the AMPL parameter solve_result_num and the relative message in solve_result.

display solve_result_num, solve_result;

CBC solve result codes can be obtained by running cbc -! or ampl: shell "cbc -!";:

Solve result table for cbc 2.10.12
          0- 99 solved: optimal for an optimization problem,
                feasible for a satisfaction problem 
        100-199 solved? solution candidate returned but error likely 
            150 solved? MP solution check failed (option sol:chk:fail) 
        200-299 infeasible 
        300-349 unbounded, feasible solution returned 
        350-399 unbounded, no feasible solution returned 
        400-449 limit, feasible: stopped, e.g., on iterations or Ctrl-C 
        450-469 limit, problem is either infeasible or unbounded.
                Disable dual reductions or run IIS finder for definitive answer.
        470-499 limit, no solution returned 
        500-999 failure, no solution returned 
            550 failure: numeric issue, no feasible solution

For general information, see MP result codes guide.

Changelog#