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NEOS Interfaces to CPLEX

Sample Submissions
WWW Form - Email - XML-RPC

CPLEX

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 CPLEX website. Additional information on all IBM software available to academics can be found on the IBM Academic Resources webpage.


Using the NEOS Server for CPLEX/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:

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.

More details can be found on the GAMS/CPLEX webpage.

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:

<email>your.address@email.edu</email>

Web Submission Form
Model File
To submit an optimization problem specified in the GAMS modeling language to the NEOS Server, you need to specify the the absolute path to the GAMS file on your system.
Options File
The Options file is optional and requires that the statement <modelname>.optfile = 1 ; exist before the solve statement in your model file. At this time, only optfile = 1 is supported; however, options may also be specified within the model input file (see the GAMS documentation).
GDX File
Optional GDX file for inputs. This file will be renamed to in.gdx. The model must include "$GDXIN in.gdx" to load this file.
Return GDX output
Return log file
Comments
Enter any additional comments here (e.g. to identify the data for your own information). These comments will be returned with your results.
Additional Settings


E-Mail address:
Please do not click the 'Submit to NEOS' button more than once.