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NEOS Interfaces to Knitro

Sample Submissions
WWW Form - Email - XML-RPC


The NEOS Server offers Knitro for the solution of:

Problems can be submitted to Knitro on the NEOS server in AMPL or GAMS format.

Knitro natively offers several other interfaces in a variety of languages: (i) object-oriented interfaces for C++, C#, Java and Python; (ii) matrix-oriented interfaces for C, Fortran, Matlab, and R; (iii) links to modelling languages AIMS, AMPL, GAMS, and MPL; (iv) and links to Excel through Frontline Solvers.

Key features of Knitro include: (i) a large set of well-documented user options (see the Knitro documentation) and automatic tuner; (ii) (parallel) multi-start for global optimization; (iii) derivatives approximation and checker; and (iv) internal presolver.

Knitro was originally developed by Richard Byrd, Mary Beth Hribar, Jorge Nocedal and Richard Waltz with additional help from Guanghui Liu, Marcelo Marazzi, Todd Plantenga, and Jose Luis Morales. Since July 2015, Knitro has been developed by Artelys with Richard Waltz as lead developer.

Free trial and evaluations of Knitro are available on the Download page of the Artelys website. For more information on Knitro, see the Artelys Knitro Overview or directly contact Artelys.

Using the NEOS Server for Knitro/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.

Web Submission Form
Model File
Specify 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 ; exists 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
The GDX file is an optional file for inputs. It will be renamed in.gdx. The model must include "$GDXIN in.gdx" to load this file.
Return GDX output
Return log file
You may enter any additional comments here, for example, 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.