NEOS Interfaces to CPLEX

Sample Submissions
WWW Form - 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
Upload the GAMS model file.
Options File
The solver options file is optional. If provided, the statement <modelname>.optfile = 1 ; is required before the solve statement in your model file. Only optfile = 1 is supported, however, options also may be specified within the model input file (see the GAMS documentation).
Parameters File
A secondary parameters file may be uploaded to NEOS. This file is optional. Note that some settings are overwritten by NEOS default settings. (See GAMS Call and CL Parameters for more details.)
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.
GAMS Restart File
A GAMS restart file can be submitted to NEOS. (See GAMS Save and Restart for more details.)
Return GDX output
Check the box to have the solver return a compressed GDX file that contains all of the symbols in the model.
Return GAMS listing file
Check the box to include the GAMS listing file in returned output.
Return log file
The log file contains information generated by the algorithm during a solve. Check the box to have the log file included in the output returned.
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.
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