DARE IIIB — a CSSL-type batch-mode simulation language for CDC 6000-series computers

Abstract

This paper describes a batch-mode FORTRAN-based continuous-system simulation language possessing most of the desirable features specified by the Simulation Council's CSSL committee. Of course, there are already many continuous-system simulation languages, such as DSL/90 and CSMP (block- oriented), MIMIC, SL-1, CSSL III, etc.; however, to the writers' knowledge, only MIMIC and CSSL III are currently available for CDC-6000 series systems. MIMIC, while equation-oriented, is not as powerful as CSSL III, is somewhat rigid in format, and hard to modify. CSSL III usage involves a surcharge to the program originator, and is thus not attractive for educational applications. DARE IIIB, locally developed under NSF sponsorship, is a modern CSSL-type language, almost as powerful as CSSL III, that is available to any potential user for the cost of a magnetic tape. DARE IIIB is structured to permit convenient user modification, e.g., it is relatively easy to add new integration rules, run-time strategies, or special library subprograms. Problem equations are entered in a form close to ordinary mathematical notation; the associated proce dural language is FORTRAN. User-chosen variable names in the problem description are accommodated by a translation phase. Run-time data is entered via standard FORTRAN IV namelist data cards. A variety of output options are provided, including line- printer listings and plots, and CalComp plotter dis plays. Single- or multiple-run problems may be specified, with storage files used for saving output data for subsequent cross-plotting, reentry into future runs, etc. In addition to an internal collection of library functions, special functions may be specified in FORTRAN, and one-or-two variable table lookup function generation is provided. DARE IIIB provides a choice of several internal fixed- and variable-step integra tion rules; the user can insert his own run-time con trol subroutine for special application. The system is presently implemented on a CDC 6400 with 65K of core memory (SCOPE 3.2 operating system), and an off-line CalComp plotter. DARE IIIB can accommodate problems with 100 parameters, 200 state variables, and 350 output variables. This paper describes the major features of the lan guage, and presents basic user information, and several examples. Inquiries regarding this software package should be addressed to Professor John V. Wait.