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, _/_/ _/ _/ _/_/_/_/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/_/ _/ _/_/ _/ _/ _/ _/ _/ _/ _/ _/_/_/_/ _/ _/ *----------------------------------------------------------------------* Dr. Nick van Eijndhoven Department of Subatomic Physics email : nick@phys.uu.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.phys.uu.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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