Faouzi Attallah wrote: > > Hi Rene, > > On Wed, 2 Dec 1998, 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 > > > > You are right as long as its a statistical error, which is not my > case where , e.g., > error = xweight/sqrt(n) ; > n being the Number of averages in Schottky spectra. > Any other suggestion.. > > Greetings, > Faouzi Hi Faouzi, If your problem is simply to draw a list of unordered points n,x[n],y[n] with associated errors ex[n],ey[n], you should use the TGraphErrors class. See an example in $ROOTSYS/tutorials/gerrors2.C Rene Brun
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