Hi Sylvie,
This problem was fixed a long time ago. your code will work if you move to
3.10/07, 4.00/08 or 4.01/04
Rene Brun
On Fri,
3 Dec 2004, Sylvie Brunet wrote:
>
> Hi,
>
> I try to plot a 2D histogram using the COLZ option.
> If I use at the sametime the option sumw2 for my histogram, the resulting
> plot has not the right scale (i.e. the color of one bin doesn't
> represent the number of entries in that bin.) If I try histo->GetSum()
> however, I get the right numbers.
>
> If I don't use sumw2, all is ok.
>
> I'm using version 3.05/05
>
> ----
>
> To reproduce the feature:
> -------------------------
>
> gStyle->SetPalette(1)
> gStyle->SetOptStat(0)
> TH2D *TH2b0 = new TH2D("TH2b0","Double tags MC B0B0bar",50,1.73,2.0,50,1.73,2.0);
> TH2b0->Sumw2()
> TH2b0->Fill(1.9, 1.8)
> TH2b0->Draw("COLZ")
>
> You'll see that the entry reprent less than one (= 0.5 ?) according to the
> color scale.
>
> GetSum is ok however:
>
> root [10] TH2b0->GetSum()
> (const Stat_t)1.00000000000000000e+00
>
> (if you don't put the TH2b0->Sumw2() line all will be ok)
>
> Is that understood?
>
> Thanks,
>
> Sylvie
>
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