Frank,
TCutg in TH2::ProjectionX,Y,etc was implemented only in version 4.01.
Rene Brun
On
Thu, 9 Dec 2004, Frank Delaunay wrote:
> Dear Rooters,
>
> I am running ROOT version 4.00.08 on intel 686 with Linux.
>
> I want to make a Projection of a TH2F histogram using a TCutG to project
> only a small region of the histogram.
> The TH2F is in file, which I first open. I draw the TH2F and draw the
> TCutG. I retrieve the cut in the interpreter and change its name.
> Then I make a ProjectionX using the name of the cut in the option, and I
> draw the TH1D projection. Nothing crashes, but the drawn TH1D is actually
> the projection of the whole TH2F and not only the region enclosed in the
> TCutG.
>
> The series of commands is:
>
> root [0] f = new TFile("../root-files/mcp1_yvsx_run1.root")
> (class TFile*)0x8de9e30
> root [1] mcp1_xvsy->Draw()
> <TCanvas::MakeDefCanvas>: created default TCanvas with name c1
> root [2] TCutG *cut = (TCutG*)c1->FindObject("CUTG")
> root [3] cut->SetName("cut")
> root [4] TH1D *px
> root [5] px = mcp1_xvsy->ProjectionX("px",0,1024,"[cut]")
> (const class TH1D*)0x903ed60
> root [6] px->Draw()
>
> Thanks for any help,
> Franck Delaunay
>
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