AMPL <description><url>http://slack.iems.nwu.edu/ampl/ampl.html</url> <title_line>for forumulating, solving and understanding optimization problems <abstract> AMPL is a language and system for formulating, solving, and helping understand mathematical programming problems (of minimizing or maximizing a function subject to constraints). A flexible interface enables several solvers to be available at once and allows a user to switch between solvers and to select options that may improve solver performance. Once optimal solutions have been found, they are expressed in terms of the modeler's notation so that they can be viewed and analyzed. All of the general set and arithmetic expressions of AMPL can also be used for displaying data and results; a variety of options are available to format data for browsing on a screen, printing reports, or preparing input to other programs. <keywords>numerical library <keywords scheme=http://gams.nist.gov/>G2. Constrained optimization <category>numerical-opt <environment> Available platforms for AMPL include IBM RS/6000, AMDAHL(UNIX), CRAY(UNIX), DOS 386/486, HP 9000, SUN SPARC, and SGI. <contact>ampl@research.att.com <comments> Netlib has an AMPL area that contains bug reports, executables compiled by Symantec and WATCOM, sample models, and sample code that demonstrates how to interfaces optimization subroutines to AMPL. </urc>