e01daf
e01daf
© Numerical Algorithms Group, 2002.
Purpose
E01DAF Interpolating functions, fitting bicubic spline, data on rectangular
grid
Synopsis
[px,py,lamda,mu,c,ifail] = e01daf(x,y,f<,ifail>)
Description
This routine determines a bicubic spline interpolant to the set
of data points (x ,y ,f ), for q=1,2,...,m ; r=1,2,...,m . The
q r q,r x y
spline is given in the B-spline representation
m m
x y
-- --
s(x,y)= > > c M (x)N (y),
-- -- ij i j
i=1 j=1
such that
s(x ,y )=f ,
q r q,r
where M (x) and N (y) denote normalised cubic B-splines, the
i j
former defined on the knots (lambda) to (lambda) and the
i i+4
latter on the knots (mu) to (mu) , and the c are the spline
j j+4 ij
coefficients.
Values of the computed spline can subsequently be obtained by
calling E02DEF or E02DFF.
Parameters
e01daf
Required Input Arguments:
x (:) real
y (:) real
f (:) real
Optional Input Arguments: <Default>
ifail integer -1
Output Arguments:
px integer
py integer
lamda (:) real
mu (:) real
c (:) real
ifail integer