Re: TH1::FillError() function

From: Nick van Eijndhoven (Nick@phys.uu.nl)
Date: Wed Dec 02 1998 - 17:33:18 MET


Rene Brun wrote:
> 
> Faouzi Attallah wrote:
> >
> > Hi Everybody
> >
> > I would like to fill up a histogram (hf) with a user-weight-error,
> > such as
> >         hf->Fill(xval, xweight)  ;
> >         hf->FillError(xval, error) ;
> >
> > The problem is my *vector(xval, xweight, error) is not sorted to
> > allow any use of TH1::SetBinContent()/SetBinError()
> > Any suggestion ..
> >
> > Greetings,
> 
>  Hi Faouzi,
> The normal procedure to fill an histogram with weights and correct
> storage of the error bars is:
>    TH1F *hf = new TH1F("hf",...
>    hf->Sumw2();
>    hf->Fill(xval,xweight);
> 
> The error in bin I will be computed by taking sqrt((sum of xweight)^2)
> 
> Rene Brun

Hi Faouzi,
If I correctly understand what you want, you could use a
TGraphErrors object instead of a TH1F.
Here you can enter points (x,y) and the errors dx and dy as you
like and you can Draw(), Fit() etc....
-- 

                                              Cheers,

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