The NEOS Server offers IPOPT for the solution of non-linear programs in AMPL format. IPOPT is an open source software package for large-scale non-linear optimization. It implements a primal-dual interior point algorithm, which uses a filter line search method to ensure global convergence. More information on IPOPT is available from the IPOPT home page. A technical report describing the algorithm can be downloaded here.
IPOPT has been developed by Andreas Wächter, Lorenz T. Biegler, Arvind Raghunathan, and Yi-Dong Lang.
The model is specified by a model file, and optionally, a data file and a commands file. If the command file is specified it must contain the AMPL solve command.
The commands file can contain any AMPL command, and may set options for IPOPT, for example
Printing directed to standard out is returned to the user with the output.
Having a rich, realistic testset is of paramount importance for the evolution of optimization solvers. Therefore, models submit to NEOS for solution with IPOPT may be used by the authors for testing and improvement of their code.
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