CURVEDERIVEVAL: Compute the derivatives of a B-spline curve.
 
 usage: ck = curvederiveval (n, p, U, P, u, d) 

  INPUT: 

        n+1 = number of control points
        p   = spline order
        U   = knots
        P   = control points
        u   = evaluation point
        d   = derivative order

  OUTPUT:

        ck (k+1) =  curve differentiated k times

 Adaptation of algorithm A3.4 from the NURBS book, pg99

    Copyright (C) 2009 Carlo de Falco
    Copyright (C) 2010 Rafael Vazquez

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

Package: nurbs