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NEOS Interfaces to Knitro

WWW Form & Sample Submissions


The NEOS Server offers Knitro for the solution of general nonconvex, nonlinearly constrained optimization problems that can be modeled in AMPL format. Knitro also can be used to solve simpler classes of problems, such as unconstrained problems, bound constrained problems, linear programming (LP) problems and quadratic programming (QP) problems.

Knitro was 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. For a detailed description of Knitro, see R. H. Byrd, J. Nocedal, and R. A. Waltz. 2006. KNITRO: An Integrated Package for Nonlinear Optimization. In: G. di Pillo and M. Roma, editors. Large-Scale Nonlinear Optimization. Springer-Verlag. p. 35-59.

Knitro is available from Artelys. For more information on Knitro, see the Knitro website.

Using the NEOS Server with Knitro

The user must submit a model in AMPL format to solve a nonlinear programming problem. The examples section of the AMPL website provides examples of models in AMPL format.

The nonlinear programming problem must be specified by a model file with the options of a data file and a commands file. If the commands file is specified, it must contain the AMPL solve command. The commands file must not contain the model or data commands. The model and data files are renamed internally by NEOS.

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:
0: automatic algorithm selection (default)
1: Interior/Direct algorithm
2: Interior/CG algorithm
3: Active algorithm
4: SQP algorithm

The commands file may include AMPL commands and option settings for Knitro. To specify solver options, add

option knitro_options "OPTIONS";

where OPTIONS is a list of one or more of the Knitro options. See the Knitro/AMPL Reference Manual for a list of the available Knitro options.

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.