Robert Walraven Fall 1983 DECUS This submittal contains three sections: 1. Equation fitting routines. See my paper (FALL 1983 DECUS) for a discussion of these routines. NOTE: these routines are definitely not optimized for speed; they were written to illustrate the principles of fitting. If you want to modify them to speed up a particular fitting application, there are many clever things you can do. Just remember to verify your modified program by comparing results with these originals. a. LINFIT - a linear model fitting routine. b. NLFIT - a non-linear model fitting routine. c. MATINV - matrix inversion routine used by LINFIT and NLFIT. d. FPOLY - a polynomial function for LINFIT. e. FCHISQ - evaluates chi-squared for NLFIT. f. FEXP - one and two exponential with background FUNCTN for NLFIT. g. DFEXP - supplies derivatives of exponential functions for NLFIT. h. EXPFIT - demonstration program for fitting exponential data. i. EXPGEN - exponential data generator for EXPFIT. 2. Digital filter routines. I recommend you read my paper from FALL 1981 DECUS on Digital Filters if you want to use these routines. a. FLTLIB - A collection of assorted routines for digital filtering: 1) FILTER - non-recursive general digital filter. 2) LOWPAS - non-recursive 9-term low-pass digital filter. 3) H OF Z NR - computes transfer function for non-recursive filter. 4) COEFS - computes coefficients for recursive digital filters. 5) H OF Z R - computes transfer function for recursive filter. b. FLTREC - a recursive digital filter. c. FLTPLT - plots transfer function of digital filter. 3. 1st order differential equation solvers. a. ADBASH - Adam-Bashford method. b. KUTSIM - Kutta-simpson method. c. TESTAB - Demonstration program for ADBASH. d. TESTKS - Demonstration program for KUTSIM.