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Introduction to Simfit and Simdem


Simfit is an Open Source package for

  • Simulation;
  • Curve Fitting;
  • Statistics; and
  • Graph plotting.

It can be downloaded from the Simfit website at

Simfit can be used in such areas as biology (growth curves), psychology (factor analysis), physiology (transport), pharamacology (dose response curves), pharmacy (pharmacokinetics), immunology (ligand binding), biochemistry (calibration), biophysics (kinetics), epidemiology (survival analysis), medical statistics (meta analysis), chemistry (chemical kinetics), physics (dynamical systems), and mathematics (numerical analysis).

Clipboard data can be analyzed, there is a fully featured pdf user manual with hyper-links, and macros to interface with MS Excel are provided.


The Simdem package is an Open Source implementation of the front-end to the Windows API that was created using Clearwin+ to enable Simfit to run in Windows. It is now included in the standard Silverfrost release.

Simdem consists of documentation, and 70 demonstration programs in standard Fortran to illustrate how to create controls for input/ouput, and graphics files in .eps, .emf, .bmp, .pcx, .jpg, .png, tif, and .svg formats, using only standard conforming Fortran code, with no direct references to winio@, or any other FTN95 library routines. The Simdem library implementation uses three DLLs as follows:

  1. w_menus.dll (standard Fortran);
  2. w_graphics.dll (standard Fortran); and
  3. w_clearwin.dll (FTN95 specific code and auxiliaries).

Users of FTN95 have only to supply references to these three DLLs in Plato, or on the command line to Slink, to be able to build fully featured executables with menus, dialogues, graphics, extensive file handling procedures, and a mini spreadsheet type numerical editor, without any need to use calls to winio@. This is because all the code required to transform standard Fortran calls into calls to the Windows API via winio@ are taken care of by w_clearwin.dll. Of course, the Simdem DLLs can also be used by executables that call winio@ directly, or link to any other DLLs, or static libraries.

For more detailed information see simdem.chm.



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