TGraph2DErrors Class Troubles

From: Danilo Piparo <Danilo.Piparo_at_mib.infn.it>
Date: Wed, 15 Jun 2005 17:16:27 +0200 (CEST)

Hello,
I encountered the following problems working with TGraph2DErrors class:

1.I don't know how to display points errorbars drawing a TGraph2DErrors object.

2.I fitted a TGraph2DErrors with a TF2 function (fit params are ok). I can't correctly display the function in the same Canvas where the TGraph2DErrors object is.

        Could Anyone help?

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Here is the Code of the Macro I used:

double getXmin(TGraph* g)
{

  double s = g->GetN () ;
  double* asseX = new double[s] ;
  asseX = g->GetX () ;
  double minimo = asseX[0] ;
  //delete [] asseX ;
  return (minimo) ;
}

double getXmax(TGraph* g)
{

  double s = g->GetN () ;
  double* asseX = new double[s] ;
  asseX = g->GetX () ;
  double massimo = asseX[s-1] ;
  //delete [] asseX ;
  return (massimo) ;
}

int primo()
{

  TFile f ("output_gra.root") ;
  f.cd () ;

  TGraph2DErrors * pluto = new TGraph2DErrors () ;   TGraph * pippo ;
  int r = 0 ;
  double * point ;
  double * epoint ;

  for (int phi=0 ; phi<90 ; ++phi)
    {

      char nome[80] ;
      sprintf (nome,"piccoRing_%d",phi) ;
      pippo = (TGraphErrors* ) f.Get (nome) ;
      if (pippo)
        {    
	  int l = pippo->GetN () ;
	  point  = new double[l] ;
	  point  = pippo->GetY () ;
	  epoint = new double[l] ;
	  epoint = pippo->GetEY();

          double min = getXmin(pippo) ;
	  double max = getXmax(pippo) ; 
	  
	  
	  
	  for (int eta = 0 ; eta < max-min ; ++eta)
	    { 
// 	              std::cout << "r,eta,phi,point,ep = " 
// 	       	                << "r: " << r
// 	       	                << " point[" << eta << "] : " << 
point[eta]
// 				<< " epoint[" << eta << "] : " << 
epoint[eta]
// 	                               << std::endl ;
 	      pluto->SetPoint (r,
 	                       eta,phi,
 	                       point[eta]) ;
       	      pluto->SetPointError (r,0,0,epoint[eta]) ;
	      
	      ++r;
	    }
	  delete [] point;
       	  delete [] epoint;
 
        }    

    }   

  TCanvas c1 ;   

  TF2 *f1 = new TF2("f1","[0]+ [1]*x + [2]*y",0,35,0,40);

  f1->SetParameter(0,-0.003);
  f1->SetParameter(1,0);
  f1->SetParameter(2,0);

  pluto->Fit(f1);

  //D Maquillage

  pluto->GetXaxis()->SetTitle("eta");
  pluto->GetYaxis()->SetTitle("phi");
  pluto->GetZaxis()->SetTitle("peak");
  pluto->GetXaxis()->SetTitleOffset(1.45);
  pluto->GetYaxis()->SetTitleOffset(1.45);
  pluto->GetZaxis()->SetTitleOffset(1.45);
  pluto->SetTitle("Peak Vs eta-phi");
  pluto->SetMarkerStyle(6);
  pluto->SetMarkerSize(0.4);
  pluto->SetMarkerColor(46);
  

  f1->Draw("surf");
  pluto->Draw ("P0 same") ;

  c1.SetBorderMode(0);
  c1.Print ("piccoetaphi2D.eps","eps") ;
  c1.Print ("piccoetaphi2D.ps","ps") ;
  c1.Print ("piccoetaphi2D.gif","gif") ;

  TFile g ("piccoetaphi2D.root","RECREATE") ;   g.cd () ;
  pluto->Write () ;
  g.Close () ;
}

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Received on Wed Jun 15 2005 - 17:26:16 MEST