Parametric cubic spline‐fitting programs for open and closed curves Free

Three numerical recipes are given using Ahlberg’s algorithm for the parametric fitting by cubic splines of a set of n‐dimensional data points; subroutine SPLINE for an open curve, PSPLINE for a closed curve, and EPSPLINE for an axially symmetric surface (surface of revolution). Parametric routines are not troubled by intersections, and offer more flexibility in dealing with boundary conditions. One subroutine call is required for each data dimension. The execution speed of all programs is comparable to standard routines for an open curve.