General Equation Modeling Systems (GEMS)- a mathematical simulation language

This paper describes extensions of and improvements to an efficient numerical integration method, the Implicit Modeling Package (IMP), which was presented in the July 1974 issue of SIMULATION and subsequent ly in the July 1979 issue of SIMULATION. The exten sion described here is a simulation language, General Equation Modeling System (GEMS), for the solution of systems of algebraic and differential equations. GEMS provides a simple and convenient way to formulate complex mathematical models for simulation using the IMP algorithms. GEMS is well suited for the solution of sets of stiff, nonlinear algebraic and differential equations. The GEMS package is compared to ACSL (Advanced Continuous Simulation Language) using a set of nine benchmark problems.