No TVirtualFitter::DoFit()?

Hi,

Is it really true that TVirtualFitter doesn’t have an interface to ask the derived class to actually do a fit? If this is really the case… why?

mike

The minization is started via TVirtualFitter::ExecuteCommand

Cheers,
philippe

But this requires you to know something about the derived class (namely, the interface… actually more than that, the very details of the implementation). It’s not good…

mike

Mike,

see my reply to your other post at:
savannah.cern.ch/bugs/index.php?20634

Rene

[quote=“brun”]Mike,

see my reply to your other post at:
savannah.cern.ch/bugs/index.php?20634

Rene[/quote]

I see. Ok. For the record, I’m trying to implement a general purpose likelihood surface scan in two dimensions. It takes a list of values of two fit parameters (e.g. as the bin centers of a TH2), fixes them, then minimizes with respect to all the others. From this I derive confidence levels. TMinuit::Contour() can already find such contours but it has troubles, particularly when one parameter is near a limit. Solving this for a particular case (involving a fit with TFractionFitter) is my pressing motivation as TMinuit::Contour() seems to find its way into an unphysical region. Anyway, I’d like to make my solution general (maybe it could be added to ROOT eventually) so that other minimizers could be used.

mike