Re: Drawing part of a TGraphErrors

Dear Olivier,

1. feb. 2007 kl. 17.42 Olivier Couet wrote:

> May be something like that would be simpler:
>
> {
> Int_t n=20;
> Double_t x[n],y[n];
> for (Int_t i=0; i < n; i++) {
> x[i]=i*0.1;
> y[i]=10*sin(x[i]+0.2);
> }
> TGraph *gr1 = new TGraph (n,x,y);
> TAxis *axis = gr1->GetXaxis();
>
> axis->SetLimits(0.,5.); // along X
> gr1->GetHistogram()->SetMaximum(20.); // along
> gr1->GetHistogram()->SetMinimum(-20.); // Y
>
> gr1->Draw("AC*");
> }
>

Thanks so much for your suggestion, but unfortunately it doesn't help me. The data file I am reading to get the TGraphErrors contains zeroes, and if I plot the whole graph also the zero points appear with markers. This I would like to avoid, and therefore I tried to use the DrawGraph function, which is perfect for a TGraph.

Cheers, Cecilie

> From: owner-roottalk_at_pcroot.cern.ch [mailto:owner-
> roottalk_at_pcroot.cern.ch] On Behalf Of Ann-Cecilie Larsen
> Sent: Monday, February 19, 2007 5:24 PM
> To: RootTalk
> Subject: [ROOT] Drawing part of a TGraphErrors
>
> Dear Rooters,
>
> I am trying to plot only a part of a graph with error bars using
> the following statements in my macro:
>
> // make graph
> TGraphErrors *gr_fg3 = new TGraphErrors
> (n,energy,fg3,xerr,fgerr3); // for fg
> // creating histogram (just for the axis)
> TH2F *h1 = new TH2F("h1"," ",10,0.0,8.0,10,0.0,1.0);
> h1->Draw(); // draw axis
> gr_fg3->SetMarkerStyle(21);
> gr_fg3->SetMarkerSize(0.6);
> gr_fg3.DrawGraph(8,&gr_fg3->GetX()[5],&gr_fg3->GetY()[5],"P"); //
> draw fg data
>
> But the error bars disappear in the pad... Is there another
> function than DrawGraph that should be used with the TGraphErrors?
>
> Cheers, Cecilie
>
> ====================================
> Ann-Cecilie Larsen
> Oslo Cyclotron Laboratory (http://ocl.uio.no/)
> Department of Physics, University of Oslo
> P.O.Box 1048 Blindern
> N-0316 Oslo, Norway
> Phone: +47 22 85 64 63 Fax: +47 22 85 64 22
> E-mail: a.c.larsen_at_fys.uio.no
> ====================================
>
>
Received on Mon Feb 19 2007 - 19:31:09 CET