Smooth

SMOOTH is a packaged network simulation language written in FORTRAN. It is based on the GASP TV and GERT IIIZ simulation languages and is capable of representing and analyzing models which include both continuous variables and discrete events. As a net work language, SMOOTH consists of a set of graphical symbols, users' input instructions, and a computer program. The basic symbols are nodes and branches: nodes perform specified functions on system varia bzes, while branches indicate precedence or function aZ relations between nodes. In using SMOOTH, the user models the system he wishes to study as a pair of interrelated networks and then describes the net works to the computer by means of the SMOOTH lan guage's input instructions. The SMOOTH computer pro gram analyzes the netzoork using simulation. No com puter programming or sophisticated mathematical tech nique is required on the part of the user. This paper discusses the concepts and symbols of SMOOTH and includes as an example a SMOOTH model of a lake ecosystem. SMOOTH has been used to study biological systems, environmental pollution by trace metals and insecticides, and problems in systems dy namics. It is the first network simulation language capable of analyzing models of a combined continuous discrete nature.