Re: TH1::FillError() function

Rene Brun (Rene.Brun@cern.ch)
Wed, 02 Dec 1998 17:02:16 +0100

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