How to get the fit status using MINOS technique

Roofit and RooStats
1

Hello everyone,

I need some help to access the resulting data after fitting an histogram. I don’t have any problem accessing to the status of the fit, using:

TFitResultPtr res = hist->Fit("myfit","LS","",xmin,xmax); int FinalStatus=int(res);

Where FinalStatus will be 0 if the fit is OK, and different if I get some errors.

However, when I try to get a better error calculation, using the parameter ‘E’ (MINOS technique), I always get ‘0’ in return:

TFitResultPtr res = hist->Fit("myfit","LES","",xmin,xmax); int FinalStatus=int(res);

i.e.: In this last case, FinalStatus is always zero, no matter the actual result of the fit.

Additionally, I read somewhere that I should define a gMinuit, and use “gMinuit->fCstatu”, but this is the old version of Minuit and I want to use the new Minuit2 package. There must be an easy way to access the status of the fit in the new package… any idea?

Thank you in advance,
J

2

Hi,

If Minos is successful you should get a zero status anyway. If Minos failed you should get a non zero status.
If you have an example showing this, cam you please post it, so I can investigate the problem

Best

Lorenzo