Module 6700
Economic Modelling with the GAMS software

Instructor

Prof. Dr. Joachim Aurbacher
Institute of Farm and Agribusiness Management,
Justus Liebig University Giessen
Senckenbergstr. 3, 35390 Giessen
Tel.: +49 641 99 37260; Fax: +49 641 99 37269
E-Mail: joachim.aurbacher@agrar.uni-giessen.de

Course Description

Many programming models require powerful solver software. The GAMS software (General Algebraic Modelling System) is unique in the number of available solvers and its flexibility in data handling and model formulation. It is widely used in economic modelling applications both on firm and on sector levels. It is capable to solve linear, non-linear and mixed integer problems efficiently and can be coupled to other software. This module offers a sound introduction into the modelling language and key economic model types that are frequently solved with GAMS. The module is structured in lectures and exercises assigned to the students.

Course Outline

1. Introduction
   • Overview
   • Motivation to use GAMS
2. Getting in touch with GAMS
   • The IDE
   • General GAMS syntax
   • Data structures
   • Process control
   • Model formulation statements
   • The solver call
3. The output of GAMS
   • The log and listing files
4. Special GAMS syntax
   • Compile time and run time commands
   • The “dollar” syntax
   • Dynamic sets
   • Data input and output via text and csv files
   • Data input and output via Excel files
5. Examples for GAMS applications in research
   • Positive and normative approaches
   • Linear models on firm and household level
   • Nonlinear models
   • Integration of bio-economic and environmental issues
6. Advanced topics
   • Interpretation of results
   • Sensitivity analysis
   • Solver choice and other options

Teaching methods

Lectures and demonstrations (50%), exercises (50%)

Grading: Tutorship for Exercises (30%), final in-class exam (70%)

Credit points: 3 CP

Requirements: Good knowledge in the fundamentals of microeconomics

References

• Rosenthal, R.E., 2014. GAMS - A User's Guide, Washington DC. https://www.gams.com/latest/docs/UG_Tutorial.html
• McCarl, B.A., Meeraus, A., van der Eijk, P., Bussieck, M., Dirkse, S., Steacy, P., Nelissen, F., 2014. McCarl GAMS User Guide, Version 24.1. https://www.gams.com/mccarlGuide/gams_user_guide_2005.htm
• Hazell, P.B.R., Norton, R.D., 1986. Mathematical Programming for Economic Analysis in Agriculture, New York. http://www.ifpri.org/publication/mathematical-programming-economic-analysis-agriculture
• Ragsdale, C.T., 2011. Managerial Decision Modeling - International Edition, Cincinnati, OH.

Software: GAMS (download of free demo version at http://www.gams.com/), additionally MS-Office
Language: English
Organization: The course will be organized as a one-week block module.