*** Nick van Eijndhoven wrote :
>
> >
> Hi Rene,
> Last night I found a solution for the problem which for me is elegant
> enough and provides all flexibility.
> Here follows the essential part of my code, which not only subtracts the
> histos but also determines the errors.
> Since this is a rather simple thing to do, I would say there is no need
> for a new member function.
>
>
> siga1 = new TH1F("siga1","Signal A1",nbl,0.,2.);
> fp_fit = new TF1("fp_fit","pol0",0.3,2.);
>
> float err1,val1;
> float err2,val2;
> float err,val;
> float x,fx;
> for (int i=0; i<nbl; i++)
> {
> val1=cnvtlgc->GetBinContent(i+1)/nclgc;
> val2=pnvtlgc->GetBinContent(i+1)/nplgc;
> x=cnvtlgc->GetBinCenter(i+1);
> fx=fp_fit->Eval(x);
> val=val1-fx*val2;
> err1=cnvtlgc->GetBinError(i+1)/nclgc;
> err2=pnvtlgc->GetBinError(i+1)/nplgc;
> err=sqrt((err1*err1)+(err2*err2));
> siga1->Fill(x,val);
> siga1->SetBinError(i+1,err);
> }
>
I forgot to mention that of course the fp_fit represents a fit to another
histo, i.e. 'hist->Fit("fp_fit","rq0,"",0.3,2.)' which should of course
follow directly after the creation of fp_fit.
*----------------------------------------------------------------------*
Dr. Nick van Eijndhoven Department of Subatomic Physics
email : nick@fys.ruu.nl Utrecht University / NIKHEF
tel. +31-30-2532331 (direct) P.O. Box 80.000
tel. +31-30-2531492 (secr.) NL-3508 TA Utrecht
fax. +31-30-2518689 The Netherlands
WWW : http://www.fys.ruu.nl/~nick Office : Ornstein lab. 172
----------------------------------------------------------------------
tel. +41-22-7679751 (direct) CERN PPE Division / ALICE exp.
tel. +41-22-7675857 (secr.) CH-1211 Geneva 23
fax. +41-22-7679480 Switzerland
CERN beep : 13+7294 Office : B 160 1-012
*----------------------------------------------------------------------*
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