Abstract
This paper describes a batch-mode FORTRAN-based continuous-system simulation Language that retains the features of the DARE family of languages 1,2,3 but is structured to facilitate implementation on a wide variety of computer systems. Except for a small set of necessarily system-dependent routines (for character packing and unpacking, job abortion, etc.) the system is coded entirely in FORTRAN IV. It is highly modular, and uses system-independent FORTRAN-based methods for writing and manipulating solution files on mass storage. The system has thus far been run on a CDC-6400 (requiring about 21,000 decimal words of core memory), and a DEC-10 (requiring about 17,000 words). This paper announces the availability of DARE P, which we plan to make available to interested users who would like to implement it on their particular system, without the usual high surcharge that often accompanies other similar software packages.
Our DARE IIIB, 3 which was specifically coded for the CDC-6000 series computers (including a COMPASS assembly-language translator overlay), was not portable. It has, nevertheless, been distributed and successfully used at many installations around the world. DARE P (Differential Analyzer REplacement- Portable) has been developed in response to requests for a version that would run on other computers. It is easy for the user to modify, e.g., he can easily add new integration rules, run-time strategies, or special library subprograms. DARE P can accommo date problems with 100 parameters and 200 state or output variables.
In DARE P problem equations are entered in a form close to ordinary mathematical notation; the associ ated procedural language is FORTRAN. User-chosen variable names in the problem description are accommo dated by a special translator overlay which translates DARE problem statements into FORTRAN IV subprograms and builds a communication file. Run-time data is entered via free-form data cards. A variety of out put options are provided, including line-printer listings and plots, and CalComp plotter displays.
Complete simulation studies may be directed by a FORTRAN-coded logic block. 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. DARE P includes an internal collection of library functions, and the user may add his own special functions written in FORTRAN and his own one- or two-variable table-lookup function- generators. DARE P provides a choice of several internal fixed- and variable-step integration routines.
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