ON THE DEVELOPMENT OF A GENERAL ALGEBRAIC MODELING SYSTEM IN A STRATEGIC PLANNING ENVIRONMENT

This article, On the Development of a General Algebraic Modeling System in a Strategic Planning Environment, was reprinted with permission from the 1982 volume of Mathematical Programming Study. It highlights and explains modeling activities at the World Bank. The Bank represents a strategic planning environment in which mathematical models have a potentially important role to play. Barriers to the effectiveness of models include extensive resource requirements, low reliability, and communication problems. In response, this paper examines requirements for successful modeling applications. It describes the resulting development of a General Algebraic Modeling System (GAMS), which employs a rigorous algebraic representation of data and equations, coupled with relational database-type facilities. The paper analyzes the data structure of this system in some detail, and draws comparisons to other modeling systems designed for large-scale linear programming problems. Selected aspects of the language are presented. The paper concludes with a case study of investment planning in the Egyptian Fertilizer Sector. In the case study, the model was used as a moderator, and was continuously modified as the planning process took place. GAMS was used as the basic modeling tool.