NRBMEASURE: Compute the distance between two given points along a NURBS curve.
 
 Calling Sequence:
 
  [dist, ddistds, ddistde] = nrbmeasure (nrb)
  [dist, ddistds, ddistde] = nrbmeasure (nrb, s, e)
  [dist, ddistds, ddistde] = nrbmeasure (nrb, s, e, tol)
 
 INPUT:
 
   nrb	: a NURBS curve, see nrbmak.
   s   : starting point in the parametric domain.
   e   : ending point in the parametric domain.
   tol : tolerance for numerical quadrature, to be used in quad.
 
 OUTPUT:
 
   dist   : distance between the two points along the NURBS curve.
   ddistds: derivative of the distance function with respect to the point s.
   ddistde: derivative of the distance function with respect to the point e.
 
 Description:
 
   Compute the distance between two given points along a NURBS curve, using 
   quad for numerical integration. The points are given by their coordinates
   in the parametric domain.

 Examples:

  Compute the length of a circular arc constructed as a NURBS.

   c = nrbcirc (1, [0 0], 0, pi/2);
   s = 0; e = 1;
   l = nrbmeasure (c, s, e, 1e-7);

 Copyright (C) 2013 Carlo de Falco
 
   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