Data Fitting and Experimental Design in Dynamical Systems with EASY-FIT ModelDesign - User's Guide

K. Schittkowski, Report, Department of Computer Science, University of Bayreuth (2009)
Abstract: EASY-FIT ModelDesign is an interactive software system to identify parameters in explicit model functions, dynamical systems of equations, Laplace transformations, systems of ordinary differential equations, differential algebraic equations, or systems of one-dimensional time-dependent partial differential equations with or without algebraic equations. Proceeding from given experimental data, i.e., observation times and measurements, the minimum least squares distance of measured data from a fitting criterion is computed, that depends on the solution of the dynamical system. Moreover, it is possible to predetermine an optimal experimental design by fixing the model parameters. Additional design parameters, for example initial concentrations or input feeds, are used to minimize the size of confidence intervals. Weight optimization helps to identify relevant time values where experiments can be taken.

The software system is implemented in form of a database under Microsoft Office Access 2007 running under Windows XP or higher, and comes with the royalty-free runtime version. The underlying numerical algorithms are coded in Fortran and are executable independently from the interface. Model functions are either interpreted and evaluated symbolically by a program called PCOMP permitting automatic differentiation of nonlinear model functions, or by user-provided Fortran subroutines.

The documentation gives an extensive review of the applied techniques, the underlying numerical routines, the declaration of model functions, the data  definitions, and the generated output. The usage of the GUI and the  underlying Fortran codes is outlined, and a set of 1,300 test examples is described which is part of the database. The report comes with about 500 references.

To download the report, click here: easy_fit.pdf

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