interp

interp — interpolation

Calling sequence

[f0 [,f1 [,f2 [,f3]]]]=interp(xd,x,f,d)  

Parameters

xd : real vector
x,f,d : real vectors from spline
fi : vectors (derivatives)

Description

given three vectors (x,f,d) defining a spline function (see splin) with fi=S(xi), di = S'(xi) this function evaluates S (resp. S', S'', S''') at xd(i).

x: vector of xi (x(1) < x(2) < ...)
f: vector of S(xi)
d: vector of S'(xi)
f0: vector [S(xd(1),S(xd(2)),S(xd(3)),...]
f(1 2 3): vector of first, second, third derivative of S at xd=[xd(1),xd(2),...] i.e.

f1 = [S'(xd(1)),S'(xd(2)),...]

f2 = [S''(xd(1)),S''(xd(2)),...]

f0, f1, f2, f3 matrices have the same shape as xd. In versions 2.7 and earlier f1, f2, f3 were transposed.

See also

splin, smooth, interpln