Hi Norbert,
Instead of:
root[0] hRecon = new TH1F("hRecon","hRecon",50,0,60);
root[1] f2 = new TFile("/data4/calfiles/mt6125eve08_A.cal.root");
do
root[0] f2 = new TFile("/data4/calfiles/mt6125eve08_A.cal.root");
root[1] hRecon = new TH1F("hRecon","hRecon",50,0,60);
The problem is that TTree::Draw looks for an histogram named "hRecon"
in the current directory.
Rene Brun
Norbert Danneberg wrote:
>
> Hi ,
>
> I have a problem using the TTree:Draw in root 2.24/01.
>
> I create a new Histogram:
> root[0] hRecon = new TH1F("hRecon","hRecon",50,0,60);
>
> open a file
> root[1] f2 = new TFile("/data4/calfiles/mt6125eve08_A.cal.root")
>
> now I want to draw part of the tree into the histogram.
> root[2] Events->Draw("TotalEnergy>>hRecon")
>
> Root creates a new canvas which contains a histogram with the data,
> but the axis range is not from 0 to 60 as defined for the histo
> "hRecon",
> but automaticly choosen by TTree::Draw()
>
> But when I try to draw the histogram with
> root[3] hRecon->Draw()
>
> the histogram is empty.
>
> Thanks,
> Norbert
>
> --
>
> Norbert Danneberg
>
> ETH Zurich - Institute for Particle Physics
> Laboratory for Nuclear Physics Phone.: +41-1-633-2034
> Hoenggerberg Fax.: +41-1-633-1067
> CH-8093 Zurich
>
> ETH Zurich - Institute for Particle Physics
> Paul Scherrer Institute Phone.: +41-56-310-3284
> CH-5232 Villigen PSI Fax.: +41-56-310-4362
>
> email: Norbert.Danneberg@psi.ch
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