Perl package for numeric 1st and 2nd order differentiation

 Math::Derivative exports functions for performing numerical first
 and second order differentiation on data. The functions take
 references to two arrays containing the x and y ordinates of the data
 and return an array of the 1st or 2nd derivative at the given x
 ordinates. The 2nd derivative may optionally be given values to use
 for the first derivative at the start and end points of the data -
 otherwise 'natural' values are used.