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Two Ways to Run GAMS. GAMS / MPSGE Course: Yerevan, Armenia May 3 – 7, 2010. GAMS – Generalized Algebraic Modeling System Strength: “Optimization” History: Originated in 1990 at World Bank F inanced later by Oil-refineries
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Two Ways to Run GAMS GAMS / MPSGE Course: Yerevan, Armenia May 3 – 7, 2010
GAMS – Generalized Algebraic Modeling System • Strength: “Optimization” • History: • Originated in 1990 at World Bank • Financed later by Oil-refineries • Now used by economists, chemists, and other scientists who need optimization • Company is small (4-5 people), based in Georgetown, Washington, DC. Introduction to GAMS
GAMS is a “modular” system • Base GAMS is the general data-management and data-manipulation part. • GAMS “solvers” are separate plugin style software developed by outsiders, for example: • MINOS: Non-Linear Program (NLP) solver, by academics at Stanford U. • CONOPT: NLP developed by professor in Netherlands • PATH: Mixed-Complimentary Solver (MCP) developed at U. Wisconsin (Madison) Structure of GAMS
For 20 years, GAMS has been a “command-line” program • In 2005, GAMS developed “GAMS-IDE” – the “Integrated Development Environment” • IDE is a Graphical Interface for the Command-Line software Using GAMS: GUI or Command?
You get a “GUI” where you can edit the program • But files are placed in a strange location: • C:\users\lightm\Documents\gamsdir\projdir\trnsport.gms GAMS IDE
Pros: • Easy to get started • Point and click • Automatically organizes files / folders • Integrated text editor • Cons: • Hard to understand what happens in “background” • File locations are un-intuitive • Always need a “project dir” • Text-editor is weak GAMS IDE: PROs and CONs
Original GAMS uses a “command Line” (MS-DOS) • A separate Text Editor is required • Input and Output files are standard “text files” • No GUI • Must learn commands in MS-DOS Traditional GAMS
Pros: • Easier to see where files are • More powerful text editor • Doesn’t require the mouse • Cons: • Harder to get Started • Requires learning about your computer • Can’t easily use the mouse • Must learn to use a text editor • Must learn to use MS-Dos commands GAMS + Epsilon