On May 16, 2011, at 9:09 PM, Stephen Pate wrote:

> Dear Rooters
> 
> 	I want to create a class, with the following characteristics:
> 
> (1) reads in private data at the time the class object is instantiated
> (2) has a member function that will calculate a chi-squared comparing that data to a model
> (3) has another member function that will perform a fit using the member chi-squared function, calling on minuit/migrad to do so
> 
> I would like to use the interpreter, not compiled code, at least in the beginning while I am developing my process.
> 
> (1) and (2) are standard things to do, but in trying to do (3) I run into the problem that the address of the member chi-squared function cannot be passed to the "SetFCN" or "SetFunction" call because it "is not defined in current scope".  I can call from one member function to another, no problem, but I can't pass the address of the member chi-squared function to the fitter interface.
> 
> 	All of the code works as long as I don't try to wrap it all into a class; it is only when placed inside a class that the call to "SetFCN" or "SetFunction" does not work.
> 
> 	There are many fitting interfaces in ROOT.  I have tried to do this using TVirtualFitter; I also tried a combination of ROOT::Math::Minimizer, ROOT::Math::Factory, and ROOT::Math::Functor; both methods were successful until placed inside a class.  It occurs to me that I have simply not tried the right interface yet, or that I need to do something additional to be able to get the address of the member function.  I hope someone can help me to do this.
> 
> 	I am using ROOT 5.28/00c on a MacBook Pro 10.6.7, i.e. everything is up-to-date.
> 
> 	thanks,
> 		Steve Pate
>