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NEOS Interfaces to Bonmin

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

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 Waechter

Information about Bonmin can be found on the Bonmin homepage on the COIN-OR website. Bonmin is a hybrid between two classical algorithms for mixed-integer nonlinear programming: an outer-approximation-based branch-and-cut-based algorithm and a pure branch-and-bound algorithm. The user can set options to declare which version of the algorithm should be employed through NEOS.

Using the NEOS Server with Bonmin

The user must submit a model in AMPL format to solve a mixed-integer nonlinearly constrained optimization problem. Examples of models in AMPL format are available from the MacMINLP library.

The mixed-integer nonlinear programming problem must be specified by a model file with the options of a data file and a commands file. If the commands file is specified, it must contain the AMPL solve command. The commands file must not contain the AMPL model or data commands. The model and data files are renamed internally by NEOS.

Bonmin has a variety of options that can be set to alter the behavior of the algorithm. The Bonmin User's Manual describes all the solver options available to the user. There are two ways to set options for Bonmin:

  • The AMPL commands file can be used to set options for Bonmin. To specify solver options, add
    option bonmin_options "OPTIONS";
    where OPTIONS is a list of one or more of the Bonmin options.
  • The user can specify the name of a local options file bonmin.opt, which includes the list of one or more of the Bonmin options.

Enter the location of the AMPL model (local file)
Model File:

Enter the location of the AMPL data file (local file)
Data File:

Enter the location of the AMPL commands file (local file)
Commands File:

Enter the location of the Bonmin options file (local file)
Options File:


Dry run: generate job XML instead of submitting it to NEOS
Short Priority: submit to higher priority queue with maximum CPU time of 5 minutes
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