An interactive graphics-based linear, integer and goal program modelling environment

Model development packages have, in recent years, become a standard tool for the development of linear and integer programs. This can be seen by the popularity of such algebraic modelling languages as GAMS, AMPL, etc. Traditionally, they have been designed around text based systems, and therefore offer a formal and structured declarative language for model definition. However, with the onset of graphics-based operating systems, standard graphical screen objects can be utilised to offer a fully interactive and guided model development package. It is noted by Greenberg that providing analysis tools to the modeller offers a form of intelligent computer assistance. Therefore, it is a natural extension to the modelling package to provide an encapsulated environment for the investigation and development of linear, integer and goal programs. A complete interactive graphics-based environment for the process of developing, solving and analysing linear, integer and goal programs (named MoGLI) is presented. The specifications of the package are discussed for such an environment. User-interface screens for model definition are introduced and described, together with a formal algebraic modelling language developed primarily for model processing, although model definition can be performed in either mode. The integration of analysis tools such as preprocessing routines and infeasibility analysis routines is also described, together with standard model information screens.