Bonmin

The NEOS Server offers Bonmin (Basic Open-source Nonlinear Mixed INteger programming) for the solution of mixed-integer nonlinearly-constrained optimization problems. Bonmin is also available open source under the Common Public License. Problems for Bonmin can be submitted on the NEOS server in AMPL or GAMS format.

Bonmin is an experimental open-source C++ code for solving general mixed-integer nonlinearly constrained problems. Bonmin features several algorithms

• B-BB is a NLP-based branch-and-bound algorithm,
• B-OA is an outer-approximation decomposition algorithm,
• B-QG is an implementation of Quesada and Grossmann's branch-and-cut algorithm,
• B-Hyb is a hybrid outer-approximation based branch-and-cut algorithm.

Bonmin was developed by a large team of researchers at IBM and Carnegie Mellon:

• Pierre Bonami
• Lorenz Biegler
• Andrew Conn
• Gerard Cornuejols
• Ignacio Grossmann
• Carl Laird
• Jon Lee
• Andrea Lodi
• Francois Margot
• Nicolas Sawaya
• Andreas Wächter

Using the NEOS Server for Bonmin/GAMS

The user must submit a model in GAMS format to solve an optimization problem. For security purposes, the model submitted must adhere to the following conventions:

• It must be self contained, i.e., no $include or $batinclude statements.
• It may not execute external programs, i.e., no $call or execute statements.
• No file creation, i.e. no put files or $echo except for a file named 'results.txt'. Other files created in the GAMS model file will be deleted.

If you are unfamiliar with GAMS, the GAMS Documentation includes a GAMS Tutorial and User's Guide. Examples of models in GAMS format can be found in the GAMS model library.

By default, the NEOS Server limits the amount of output generated in the listing file by turning off the symbol and unique element list, symbol cross references, and restricting the rows and columns listed to zero. This behavior can be changed by specifying the appropriate options in the model file. See the documentation on GAMS output for further information.

You may optionally submit an options file if you wish to override the default parameter settings for the solver. Currently, the NEOS Server can only use optfile=1 with GAMS input. Therefore, any model that specifies a different options file will not work as intended.