IPOPT¶

The COIN Ipopt solver (IPOPT) is an open-source solver for large-scale nonlinear continuous optimization. Ipopt uses an interior point method, together with a filter linear search procedure.

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How to use it¶

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

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 IPOPT

# 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="ipopt", ipopt_options="option1=value1 option2=value2")

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

Solver options¶

Full list of solver options:

IPOPT 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;

IPOPT 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

RAPOSa Options

IPOPT Options