The structure of NDTRAN — A systems simulation language

NDTRAN is a systems simulation language that is based on the principles of modeling stated by J. Forrester in his work of systems dynamics (1961, 1968) and is written in ANSI/standard FORTRAN. Because of the large number of built-in diagnostics, it is extremely easy to use, even for a beginner. In addition, it has a number of features previously lacking in other simulation packages, such as extensive user-defined and default plotting routines along with a selection of integration routines to satisfy both the technical and nontechnical person. The authors describe the unique features of its implementation.