COUENNE#

The COIN Couenne solver (COUENNE, Convex Over and Under ENvelopes for Nonlinear Estimation) is a spatial branch & bound algorithm that implements linearization, bound reduction, and branching techniques for Mixed-integer, Nonlinear Programming (MINLP) problems. The purpose of Couenne is to find global optima of nonconvex MINLPs.

How to use it#

AMPL

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

Python

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 coin # install COUENNE

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

How to use:

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

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

Other APIs

AMPL APIs are interfaces that allow developers to access the features of the AMPL interpreter from within a programming language. We have APIs available for:

Solver options#

Full list of solver options:

COUENNE Options

More details on solver options: Features guide.

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;

COUENNE solve result codes:

          0- 99 solved: optimal for an optimization problem, feasible for a satisfaction problem
        100-199 solved? solution candidate returned but error likely
        200-299 infeasible
        300-399 unbounded
        400-499 limit
        500-999 failure, no solution returned