Re: [ROOT] TF1::RejectPoint and chi^2 in stats box

From: Rene Brun (Rene.Brun@cern.ch)
Date: Mon Apr 19 2004 - 18:46:47 MEST


Hi Gero,

Gero Flucke wrote:
> 
> On Mon, 19 Apr 2004, Rene Brun wrote:
> Hi Rene,
> I don't use the likelihood option 'l', but integral option 'I'.
> 

Sorry, the two characters look similar ::)
> 
> Do you need a small script to demonstrate the problem?

Yes, please send a short script. I cannot reproduce this problem.

Rene brun

> 
> Thanks
> 
>         Gero
> 
> > Rene Brun
> >
> > Gero Flucke wrote:
> > >
> > > Hi,
> > > fitting histograms with a non-contigous function via TF1::RejectPoint
> > > works rather well, but for me it seems that the chi^2 that is shown in the
> > > statistic box ignores the rejection. I tried to get the chi^2 directly
> > > after the fit via
> > >
> > > TF1* fitFunc = ...   // my TF1 defining the function
> > > TF1* histToFit = ... // the hist that I fit
> > > histToFit->Fit(fitFunc, "EMBRI");
> > > TVirtualFitter::Fitter(histToFit)
> > >     ->Chisquare(fitFunc->GetNpar(), fitFunc->GetParameters())
> > >
> > > but that gives the same result which is also printed on screen as FCN
> > > while fitting:
> > >
> > > FCN=761.11  FROM MINOS     STATUS=SUCCESSFUL    804 CALLS <snip>
> > >
> > > How can I get the 'real' chi^2?
> > >
> > > Cheers
> > >
> > >         Gero
> > >
> > > PS: 3.10_02 on linux
> > >
> > > -----------------------------------------------------------------------
> > > Gero Flucke
> > > 1a / 603
> > > DESY
> > > Notkestr. 85
> > > 22607 Hamburg
> > > +49-(0)40-8998-2454
> > >
> > > Privat / private:
> > > -----------------
> > > Von-Hutten-Str. 20
> > > 22761 Hamburg
> >
> 
> -----------------------------------------------------------------------
> Gero Flucke
> 1a / 603
> DESY
> Notkestr. 85
> 22607 Hamburg
> +49-(0)40-8998-2454
> 
> Privat / private:
> -----------------
> Von-Hutten-Str. 20
> 22761 Hamburg



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