problem saving Graphs

From: Jose Lazoflores <Jose.Lazo-Flores_at_cern.ch>
Date: Sun, 13 May 2007 16:56:30 +0200


Hello all,

I am trying to save graphs and histograms to a root file. The histograms are saved correctly, but the graphs are not. Here is how I do it:

  TCanvas *myc = new TCanvas("myc","Slice Test Data",0,0,760,480);   myc->SetTickx();
  myc->SetTicky();

// Define a root file in which to save graphs and histograms.
  TFile *hfile = gROOT->FindObject("test.root"); if (hfile) hfile->Close();   hfile = new TFile("test.root","RECREATE","For graphs and corresponding histos");
  TH1F *sum6 = new TH1F("sum6","Sum 6 histogram",100,6e4,1e4);

  sum7->SetFillColor(48);

   gr = new TGraph(n, tmparray, myarray[5]);

   gr->SetLineColor(colornb[2]);
   gr->SetMarkerColor(colornb[2]);  
   gr->SetMarkerStyle(8);
   gr->SetMarkerSize(0.3);
   gr->SetTitle("Sum 6");
   gr->GetXaxis()->SetTitle("Time [s]");
   gr->GetYaxis()->SetTitle("Reading");
   gr->Draw("APL");
   gr->Write("Sum 6");

// fill and draw the histogram

  int value =0;
  for (int i=0; i<lines; i++) {
    if(myarray[5][i]!=0) {

      value = myarray[5][i];
      sum6->Fill(value);

    }
  }
  sum6->Draw();
  hfile->Write();

myarray[][] is a 2D array of the data I am graphing/plotting. With the above code, the histogram is saved correctly and I can open them with TBrowser and view its contents. The graph is present in the root file but it is empty when I try to view it. How do I do this properly?

Thanks,

Jose. Received on Sun May 13 2007 - 16:56:46 CEST

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