Fitpack
Researchers
Description
FITPACK is a collection of FORTRAN programs for CURVE and SURFACE FITTING with SPLINES and TENSOR PRODUCT SPLINES.Features included are automatic knot selection, error smoothing and data reduction. Besides the set of data points, the user merely has to provide a single parameter, called the smoothing factor, to control the tradeoff between closeness of fit and smoothness of fit. Confidence limits for this parameter are available if the statistical errors on the data can be estimated.
In addition to a standard routine for curve fitting over an interval and a routine for fitting a bivariate spline function to a set of scattered data on a rectangular domain, there are special programs for smoothing periodic functions, parametric curves and surfaces, functions with convexity constraints. data over the sphere and other non-rectangular approximation domains. Very efficient surface fitting routines are provided for applications with data given either on a rectangular, polar or spherical grid. Routines are included for evaluation, differentiation and integration of the spline approximations. FITPACK also contains an insertion algorithm and routines for calculating zeros and Fourier coefficients of cubic splines.
The mathematical fundamentals of FITPACK are described in the book:
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Curve and Surface Fitting with Splines, by P. Dierckx, Monographs on Numerical Analysis, Oxford University Press, 1993, (ISBN 0-19-853441-8, 286 pages, 56 line figures) |
In addition, potential FITPACK users will find there a lot of practical advice, illustrated with many examples, both purely academic as well as taken from real live.
The Fitpack routines are freely available via netlib.
Finally, it should be noted that this software has no connection with the FITPACK software package of Alan Cline.