Tools for Disjunctive Programming

A. VECCHIETTI; I. GROSSMANN

Santa Fe (Argentina)

Workshop; II Panamerican Workshop on Catalysis & Process System Engineering; 1999

Panamerican Studies on System Engineering

This paper describes a number of key modeling issues for the development of tools for solving nonlinear discrete/continuous problems where logic/disjunctive constraints are included in the formulation. A generalized hybrid representation of these problems is presented. A comparison between Constraint Logic Programming (CLP) and Generalized Disjunctive Programming (GDP) is established together with some constraints transformation from CLP to GDP. The components and expressions of a modeling language for setting up disjunctions and logic constraints is proposed. The language allows the specification of problems of arbitrary complexity. A parser is developed for the analysis and translation of the logic sentences into files ready to be used by the solvers. An overview of the solution algorithms is also given together with several aspects about the implementation as a superset of GAMS mathematical programming language.  Examples illustrating the capabilities of the proposed system are described.