The NEOS Server offers MINOS for the solution of nonlinearly constrained
optimization problems. Problems can be submitted to MINOS on the NEOS
server in AMPL or GAMS format.
MINOS is designed to solve "smooth" nonlinear programming (NLP)
problems. Smooth nonlinear functions can be accommodated in both the
objective and the constraints; nonlinear equation systems may also be solved
by omitting an objective. Nonsmooth nonlinearities are also accepted, but
MINOS is not designed for them and in general will not produce reliable
results when they are present. MINOS also offers a primal simplex method
for linear programming (LP) problems.
MINOS is suitable for large constrained problems with a linear or nonlinear
objective function and a mixture of linear and nonlinear constraints. It is
most efficient if the constraints are linear and there are not too many
degrees of freedom.
For linear programs, MINOS uses a stable implementation of the primal
simplex method. For linearly constrained problems, a reduced-gradient
method is employed with quasi-Newton approximations to the reduced Hessian.
For nonlinear constraints, MINOS implements a sequential linearly
constrained algorithm derived from Robinson's method. Step length control
is heuristic, but superlinear convergence is often achieved.
MINOS was developed by Bruce A. Murtagh and Michael Saunders.
Further details on MINOS can be found in the MINOS User's
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:
If you are unfamiliar with GAMS, the
GAMS Documentation includes a
GAMS Tutorial and
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.
<modelname>.optfile = 1 ;
optfile = 1