Herman J. Woltring
GCVSPL is a Fortran package for spline smoothing and differentiation, by the late Herman J. Woltring. The methods were described in Woltring HJ (1986) A FORTRAN package for generalized, cross-validatory spline smoothing and differentiation. Adv. Engng. Softw. 8:104-113. Woltring has shown that spline smoothing is equivalent to a double Butterworth filter (see Release Notes). The differences are that with splines it is possible to process data with unequal sampling intervals and the boundary conditions are well defined. The original subroutine package is available, as well as versions for C and Matlab programmers. Also some front-end programs for UNIX and PC.
pdf gcvspl.memo (3 KB) - Release Notes (read first)
pdf gcvspl.f (46 KB) - Subroutine package - VMS Fortran version
pdf gcvspl.fortran (54 KB) - Subroutine package - Fortran 77 version
pdf gcvtst.fortran (6 KB) - Demo/Test Program - including Vaughan's falling golf ball data
