Re: [ROOT] FitSlicesX/Y

From: Rene Brun (Rene.Brun@cern.ch)
Date: Thu May 18 2000 - 09:36:44 MEST


Hi Eddy,
Could you clarify your problem ? TH1::FitSlicesX/Y has a parameter "cut"
to reject slices with a number of entries (not the sum of weights) less than
cut.

Rene Brun

Eddy Offermann wrote:
> 
> Dear Fons and Rene
> 
> TH1::FitSlicesY and X are giving me troubles. I have a TH2D which
> contains fractions between -1 and 1.
> Unfortunately, nentries is an integer and I fail the (nentries ==0) test
> hpx->GetEntries() should not be cast to an integer, I wonder also
> why cut is an integer ??
> 
>    //Loop on all bins in Y, generate a projection along X
>    Int_t bin;
> ==>Int_t nentries;
>    for (bin=binmin;bin<=binmax;bin++) {
>       TH1D *hpx = ProjectionX("_temp",bin,bin,"e");
>       if (hpx == 0) continue;
>       nentries = Int_t(hpx->GetEntries());
>       if (nentries == 0 || nentries < cut) {delete hpx; continue;}
>       f1->SetParameters(parsave);
>       hpx->Fit(fname,option);
>       Int_t npfits = f1->GetNumberFitPoints();
>       if (npfits > npar && npfits >= cut) {
>          for (ipar=0;ipar<npar;ipar++) {
>             hlist[ipar]->Fill(fYaxis.GetBinCenter(bin),f1->GetParameter(ipar));
>             hlist[ipar]->SetBinError(bin,f1->GetParError(ipar));
>          }
>          hchi2->Fill(fYaxis.GetBinCenter(bin),f1->GetChisquare()/(npfits-npar));
>       }
>       delete hpx;
>    }
> 
> Best Regards, Eddy



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