[ROOT] Problem with TH2::FillRandom ?

From: Laurent APHECETCHE (aphecetc@in2p3.fr)
Date: Fri Apr 21 2000 - 16:02:59 MEST 

Hi,

I am using the TH2::FillRandom method to fill histograms with some 2D
distribution.
 I was using so far the following (slightly modified here) macro, and
was happy with it (I was using quite old 2.21/08 HP-UX/CC Root version).
If I try now with Root 2.23/12 Linux RH6.1, I obtain strange result for
the Y-Projection of the histogram (h10_py)...
 Am I doing something obviously wrong or is there a problem with the
FillRandom method ?

Thanks,


---

{
  Float_t KPIMAX = 40 ;
  Int_t NCX=180 ;
  Int_t NCY=100 ;
  char fileout[80] ;

  TCanvas* c1 = new TCanvas("c1","c1",500,500) ;
  TF2* f2 = new
TF2("f2","y**[0]*exp(-y/[1])/(1+exp((y-[2])/[3]))*sin(x*3.141592653590e+00/180.0)",0,180,0,KPIMAX)
;

  f2->SetParameters(0.6,17,30,2) ;  
  f2->Draw("LEGO") ;
  c1->Update() ;
  c1->Clear() ;

  c1->Divide(2,2) ;

  TH2F* h2 = (TH2F*)f2->GetHistogram() ;
  h2->SetName("h2") ;

  h2->ProjectionX() ;
  h2->ProjectionY() ;

  c1->cd(1) ;
  h2_py->Draw() ;
  c1->cd(2) ;
  h2_px->Draw() ;
  
  TH2F* h10 = new TH2F("h10","h10",NCX,0,180,NCY,0,KPIMAX) ;
  h10->FillRandom("f2",1e5) ;

  h10->ProjectionX() ;
  h10->ProjectionY() ;

  c1->cd(3) ;
  h10_py->Draw() ;
  c1->cd(4) ;
  h10_px->Draw() ;
}                  

-- 
Dr. Laurent APHECETCHE (mailto:aphecetc@in2p3.fr) | TAPS/PHENIX/ALICE
SUBATECH-Ecole des Mines de Nantes-4 rue Alfred Kastler-44070 NANTES
cedex 03
TEL (+33/0) 2 51 85 84 17 - FAX (+33/0) 2 51 85 84 24 (France)
http://www-subatech.in2p3.fr/~photons -
http://www.phenix.bnl.gov/~aphecetc

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