Re: [ROOT] project a sub range of a histogram

From: Rene Brun (Rene.Brun@cern.ch)
Date: Wed Dec 01 2004 - 18:32:25 MET


You can get ROOT 4.01/04 binaries for RH7.3/gcc2.96 from
http://root.cern.ch/root/Version401.html

As I said in my mail, the [cutg] option was implemented only in 4.01/04.

If you have problems installing the binaries (or compiling from source) on your
platform, please let us know.

Rene Brun

ddas@veccal.ernet.in wrote:
> 
> Hi rene
> 
> thanks, I am using linux 7.3 ------------
> 
> Reading specs from /usr/lib/gcc-lib/i386-redhat-linux/2.96/specs
> gcc version 2.96 20000731 (Red Hat Linux 7.3 2.96-110)
> 
> with this version of gcc. will it work?
> earlier i had problems in indtalling 4.00 and so still working with 3.10 the old version.
> regards
> 
> > To use the [cut] option in Projections, you must use a recent
> > version like
> > 4.01/04
> >
> > Rene Brun
> >
> > ddas@veccal.ernet.in wrote:
> > >
> > >  Hello
> > >  does anybody know how to project subrange of a 2D histogram.
> > >  I tried using TCutG but somehow could not get the result.
> > >  I wanted to change by Projection X from value1 to value2 and
> > then plot that part only.
> > >  Also if somebody can explain what this SetPoint means.
> > >
> > >  Example:
> > >
> > >  {
> > >     TCanvas *c = new TCanvas("c","example",0,0,700,600);
> > >     c->Divide(1,2);
> > >
> > >     TCutG *gcut = new TCutG("gcut",8);
> > >     gcut->SetPoint(0,-0.646552,0.932203);
> > >     gcut->SetPoint(1,-1.26437,0.105932);
> > >     gcut->SetPoint(2,-0.574713,-1.10169);
> > >     gcut->SetPoint(3,0.948276,-0.338983);
> > >     gcut->SetPoint(4,1.07759,0.720339);
> > >     gcut->SetPoint(5,-0.316092,-0.0847458);
> > >     gcut->SetPoint(6,-0.45977,0.402542);
> > >     gcut->SetPoint(7,-0.646552,0.932203);
> > >
> > >     TFile f("hsimple.root")
> > >     TH2F *hpxpy = (TH2F*)f.Get("hpxpy");
> > >     TH1D *hppx = hpxpy->ProjectionX("",1,40,"[gcut]");
> > >
> > >     c->cd(1);
> > >     hpxpy->SetFillColor(kBlue);
> > >     hpxpy->DrawCopy("box");
> > >     hpxpy->SetFillColor(kRed);
> > >     hpxpy->Draw("same box [gcut]");
> > >
> > >     c->cd(2);
> > >     hppx->Draw();
> > >  }
> > >
> > >  thanks again
> > >  debasish.
> > >
> > >
> >
> >



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