C Library Functions - bspp2d (3)
calls bsplvb this is an extended version of bsplpp for use with tensor products converts the b-representation t, bcoef(.,j), n, k of some spline into its pp-representation break, coef(j,.,.), l, k , j=1, ..., m . from * a practical guide to splines * by c. de Boor
INPUT
t knot sequence, of length n+k bcoef(.,j) b-spline coefficient sequence, of length n ,j=1,...,m n length of bcoef and dimension of spline space spline(k,t) k order of the spline w a r n i n g [char46] . . the restriction k .le. kmax (= 20) is impo-
sed by the arbitrary dimension statement for biatx below, but is n o w h e r e c h e c k e d for. m number of data sets
CONTENTS
Work Area
Output
Method
WORK AREA
scrtch of size (k,k,m), needed to contain bcoeffs of a piece of
the spline and its k-1 derivatives for each of the m sets
OUTPUT
break breakpoint sequence, of length l+1, contains (in increas-
ing order) the distinct points in the sequence t(k),...,t(n+1) coef(mm,.,.) array of size (k,n), with coef(mm,i,j) = (i-1)st der-
ivative of mm-th spline at break(j) from the right, mm=1,.,m
METHOD
for each breakpoint interval, the k relevant b-coeffs of the spline are found and then differenced repeatedly to get the b-coeffs of all the derivatives of the spline on that interval. the spline and its first k-1 derivatives are then evaluated at the left end point of that interval, using bsplvb repeatedly to obtain the values of all b-splines of the appropriate order at that point.
| Nemo Release 3.1 | bspp2d (3) | June 29, 2025 |
