Hey Liam et al.

I wanted to use the numerical differentiation functions of GSL (specifically gsl_deriv_central or the GSLL equiv CENTRAL-DERIVATIVE).  Does anyone have some examples of it's usage?

i have tried this with my home brewed GSL bindings.  However, it is a bit trickier than most stuff I have played with since it involves a callback function.  The callback must be placed in a slot of a gsl_function object.  Both of these steps seem trivial enough, but I am getting some memory error that I am having trouble debugging (bringing back old nightmares of C).

Anyway, thanks for reading,
Zach