[Kst] Ways to evaluate expressions...

[Brisset, Nicolas]

Hi,

I was looking at how qtiplot does non-linear fitting (with gsl) to try
and develop a kst plugin, and it actually uses a math parser lib which
you may be interested in. It's at: http://muparser.sourceforge.net/ 
I would like to avoid the dependence on that one (gsl should be enough),
but I need to find out how to :
- compute the value of an expression at a given point (with some
numerical values assigned to the formal parameters being fitted)
- compute the (numerical) derivative of a function at a given point wrt
to a given variable

Any hint at how to do that with kst bits will be appreciated :-)

Nicolas