Usage: 
mh = lpderxest (x, h {,q {,p {,K} {,v}}})

Input: 
 x  n x 2, the data. In the first column the
independent, in the second column the
dependent variable.

 h  scalar, bandwidth. If not given, the rule of thumb
bandwidth computed by lpderrot is used.

 q  integer <=2, order of derivative. If not
given, q=1 (first derivative) is used.

 p  integer, order of polynomial. If not given,
p=q+1 is used for q<2, p=q is used for q=2.

 v  m x 1, values of the independent variable on
which to compute the regression. If not given,
x is used.

Output: 
 mh  n x 2 or m x 2 matrix, the first column is the
sorted first column of x or the sorted v, the
second column contains the derivative estimate
on the values of the first column. 