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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/AMPL

The user must submit a model in AMPL format. Examples are provided in the examples section of the AMPL website.

The problem must be specified in a model file. A data file and commands files may also be provided. If the commands file is specified, it must contain the AMPL solve command; however, it must not contain the model or data commands. The model and data files are renamed internally by NEOS.

The commands file may include option settings for the solver. To specify solver options, add

option knitro_options 'OPTIONS';
where OPTIONS is a list of one or more of the available solver options for AMPL.

Knitro offers both interior-point and active-set methods. The user may specify the algorithm by setting the Knitro/AMPL option "alg" to one of the following values:

Web Submission Form
Model File
Enter the location of the AMPL model (local file)
Data File
Enter the location of the AMPL data file (local file)
Commands File
Enter the location of the AMPL commands file (local file)
Additional Settings
Dry run: generate job XML instead of submitting it to NEOS
Short Priority: submit to higher priority queue with maximum CPU time of 5 minutes
E-Mail address:
Please do not click the 'Submit to NEOS' button more than once.