Fdvec.m

Performs arbitrary-order finite-difference differentiation of a user-supplied row or column vector. Uses central finite-difference stencils inthe middle and sided stencils of the same order of accuracy on the sides. Syntax:

                    dx=fdvec(x,npoints,order)

Parameters:

   x       - column or row vector to be differentiated

   npoints - number of points in the finite difference
             stencil

   order   - order of the derivative required