Evaluate a B-spline or its derivatives.
Given the knots and coefficients of a B-spline representation, evaluate the value of the smoothing polynomial and its derivatives. This is a wrapper around the FORTRAN routines splev and splder of FITPACK.
x : array_like
tck : tuple
der : int
ext : int
y : ndarray or list of ndarrays
|[R14]||C. de Boor, “On calculating with b-splines”, J. Approximation Theory, 6, p.50-62, 1972.|
|[R15]||M.G. Cox, “The numerical evaluation of b-splines”, J. Inst. Maths Applics, 10, p.134-149, 1972.|
|[R16]||P. Dierckx, “Curve and surface fitting with splines”, Monographs on Numerical Analysis, Oxford University Press, 1993.|