Eigenunsupported
3.3.4

This class allows you to add a method df() to your functor, which will use numerical differentiation to compute an approximate of the derivative for the functor. Of course, if you have an analytical form for the derivative, you should rather implement df() by yourself.
More information on http://en.wikipedia.org/wiki/Numerical_differentiation
Currently only "Forward" and "Central" scheme are implemented.
Inherits _Functor.
Public Member Functions  
int  df (const InputType &_x, JacobianType &jac) const 

inline 
return the number of evaluation of functor