MINTO

The NEOS Server offers MINTO for the solution of mixed-integer linear programs posed in AMPL format.

MINTO (Mixed INT Optimizer) is a mixed integer linear programming (MILP) solver that implements a branch-and-bound algorithm with linear programming relaxations. MINTO provides automatic constraint classification, preprocessing, primal heuristics, and constraint generation. It has built-in cut generation and can create knapsack cuts, GUB cuts, clique cuts, implication cuts, flow cuts, mixed integer rounding and Gomory cuts. The user can customize MINTO by implementing problem-specific application routines.

MINTO does not have its own linear programming (LP) solver. This version of MINTO uses the LP solver Clp, from the Coin-OR project to solve the relaxations.

The original authors of MINTO are: Martin Savelsbergh, Georgia Tech, and George Nemhauser, Georgia Tech. MINTO is currently maintained by Jeff Linderoth, University of Wisconsin, Madison.

References:

• Linderoth, J. T. and Ralphs, T. K. 2005. Noncommercial Software for Mixed-Integer Linear Programming. Integer Programming: Theory and Practice, John Karlof (ed.). CRC Press Operations Research Series, pp. 253-303.
• Nemhauser, G.L., Savelsbergh, M. W. P., and Sigismondi, G. S. 1994. MINTO, a Mixed INTeger Optimizer. Operations Research Letters 15: 47-58.
• Savelsbergh, M. W. P. and Nemhauser, G. L. 1998. Functional description of MINTO, a Mixed INTeger Optimizer (Version 3.0). Report COC-91-03D, Georgia Institute of Technology.
• Savelsbergh, M. W. P. and Nemhauser, G. L. 1995. A MINTO short course. Report COC-95-xx, Georgia Institute of Technology.

Using the NEOS Server for MINTO/AMPL

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.

The commands file may include option settings for the solver. To specify solver options, add

  option minto_options 'OPTIONS';

The commands file can contain any AMPL command or set options for MINTO. by modifying the variable 'mintoamp_options'. See the MINTO-AMPL options page to get a listing of the various options.

A few more items of note specific to the MINTO-AMPL solver

• The maximum CPU time for a job has been set to four hours
• The test problems submit to NEOS can and will be harvested. Problems deemed "interesting" are made available to the public (as MPS files) at COR@L
• The Osi and Clp COIN components used in the code are compiled from the COIN CVS tree on 8/3/05