The NEOS Server offers IPOPT for the solution of nonlinear programs. Problems can be submitted to IPOPT on the NEOS server in AMPL or GAMS format.
IPOPT is an open-source software package for large-scale nonlinear optimization. It implements a primal-dual interior point algorithm, which uses a filter line-search method to ensure global convergence.
The main authors of IPOPT are Andreas Wächter and Carl Laird, with additional development by Lorenz T. Biegler, Arvind Raghunathan, and Yi-Dong Lang. For more information, see the IPOPT home page. A list of papers and publications describing the algorithm is available here.
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
solve
model
data
option ipopt_options 'OPTIONS';