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652. ABACUS: Interactive Program for Nonlinear Regression
Analysis
by William Damert, U.S. Department of Agriculture, 600 E. Mermaid Lane, Philadelphia, Pennsylvania 19118 ABACUS is a program for performing nonlinear regression analysis using the Gauss-Newton iteration algorithm on x-y data input from a file. The program is written for VAX/VMS FORTRAN-77 and is distributed with a function for fitting any number of GAUSSIAN peaks and with several other common functions. It is designed so the user may easily replace the functions provided with other mathematical formulas containing parameters to be determined. The program is command driven, with commands that allow the user to select the function and options, change parameters, draw a graph of the data points overlaid with the current function, perform iterations, allow parameters to vary or force them to stay fixed in value, set bounds on parameter values, and print reports. The program has dimensions set to allow variation of up to 100 parameters and executes quickly enough to be used interactively using a GAUSSIAN function or other easily evaluated function on problems of that size. The graphics calls adhere to the GKS standard, and users may link the program with their own GKS libraries for device independent graphics. In addition, the program includes graphics drivers for a Tektronix terminal. Documentation for users and documentation for persons wishing to modify the program or to add new functions are provided. Lines of Code: 5502 FORTRAN 77 (VAX) |