"The General Algebraic Modeling System (GAMS) is a high-level modeling system for mathematical programming problems. It consists of a language compiler and a stable of integrated high-performance solvers. GAMS is tailored for complex, large scale modeling applications, and allows you build large maintainable models that can be adapted quickly to new situations." It can run on machines that vary in size from PC to supercomputers.

At this site you can read about GAMS, including solvers and supported platforms. They also offer extensive documentation (including FAQs and an index to their model library), information on contributed software, and material on workshops and courses.