The NEOS Server offers Couenne for the solution of mixed-integer
nonlinearly-constrained (MINLP) and global optimization problems.
Problems can be submitted to Couenne on the NEOS server in AMPL or GAMS
Couenne (Convex Over and Under ENvelopes for
Nonlinear Estimation) is a branch-and-bound algorithm to solve
mixed integer nonlinear programs (MINLPs) and global optimization problems.
Couenne aims to find global optima of nonconvex MINLPs. It implements
linearization, bound reduction, and branching methods within a
branch-and-bound framework. Its main components are:
Couenne was developed and is currently maintained by Pietro Belotti and
others. More details on the solver are available on the
Couenne page at COIN-OR.
The user must submit a model in AMPL
format. Examples are provided in the examples
section of the AMPL website.
The problem must be specified in a model file. A data file and commands
files may also be provided. If the commands file is specified, it must
contain the AMPL solve command; however, it must not contain
the model or data commands. The model and data
files are renamed internally by NEOS.
Options are specified in a file with one option per line with the format
of the name of the option followed by a space and the value.
Note: There is a minor bug in Couenne produces the message "infeasible solution" regardless
of the solve outcome (e.g., even when a solution is found). Details can be found