The NEOS Server offers the IBM
ILOG CPLEX Optimizer for the solution of linear programming (LP), mixed-integer
linear programming (MILP), and second-order conic programming (SOCP) problems.
Acceptable input formats for CPLEX on the NEOS server include AMPL, GAMS,
LP, MPS, and NL formats.
Details on CPLEX can be found on the IBM
Additional information on all IBM software available to academics can be
found on the IBM Academic Resources
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.
More details can be found on the
Note: An email address is required for any submissions that use CPLEX. This email address
will be forwarded to IBM and may be used by IBM for promotional purposes.
When using the XML-RPC interface, you must add the following line into the XML file that is sent to NEOS:
<modelname>.optfile = 1 ;
optfile = 1