[ROOT] problems reading TTrees

From: Jens Berger (jberger@bnl.gov)
Date: Mon Oct 14 2002 - 06:10:43 MEST 

Hi Roottalk,

I have problems to read Trees w/ events (similar to the Event.cxx example)
using this code running linux ROOT 3.02.07:
----------------------------------------------------------------------------
TROOT root("Analysis","Rich Analysis");


int main(int argc, char **argv)
{
 root.Reset();

 TString inFileList;
 TString outHistofile;
 int nEvents=0;
 int nFiles=0;

 if(argc > 1)
 {
  inFileList=argv[1];
  outHistofile=argv[2];

cout <<"dir:"<<inFileList<<" root:"<<outHistofile<<endl;
  for (int k = 1; k < argc; k++)
  {
   int c = *++argv[k];

   switch(c)
   {
    case 'n':
    k++;
    nEvents = atoi(argv[k]);
    printf("nr of events: %i\n",nEvents);
    break;

   } // switch
  } // for
 }
 else
 {
  printf ("usage: L3RICHTriggerEfficiency filelist.txt histo.root \n\n");
  printf ("       -n [Number of events(default:all)]\n");

  return 0;
 }



 // Histograms
 TH1F *hVz = new TH1F("hVz","Vertex z Pos",1000,-500,500);
 TH2F *hVyVx = new TH2F("hVyVx","Vertex y  vs.  Vertex x
Pos",20,-10,10,20,-10,10);
 TH1F *hVx = new TH1F("hVx","Vertex x Pos",50,-25,25);
 TH1F *hVy = new TH1F("hVy","Vertex y Pos",50,-25,25);


 TStopwatch timer;
 timer.Start();


 TChain *chain = new TChain("Tree");

 // Open the filelist and chain them
 FILE *fp = fopen(inFileList.Data(),"r");
 char* dataFile=new char[512] ;
 Int_t nlines = 0;
 Int_t ncols;
 while(1)
 {
  if(nFiles){ if(nlines>nFiles) break; }
  if( fscanf (fp, "%s", dataFile ) == EOF ) break ;
  if (nlines<10 || nlines%10==0) printf("add %d: %s\n",nlines,dataFile);
  chain->Add(dataFile);
  nlines++;
 }
 printf(" found %d datafiles\n",nlines);
 fclose(fp);


  Event *event = new Event();

  chain->SetBranchAddress("Event",&event);
  TClonesArray *primaries = event->GetfPrimaries();
  TClonesArray *globals = event->GetfGlobals();
  TClonesArray *l3globals = event->GetfL3Globals();

  Int_t nevent = chain->GetEntries();
  cout<<"Tree has:"<<nevent<<endl;

  Int_t nb = 0;
  for (Int_t eventCnt=0;eventCnt<nevent;eventCnt++)
  {
   printf("Tree -> Event:%d\n",eventCnt);

   chain->GetEntry(eventCnt);                  //read complete event in
memory
   cout<<"primaries:" << primaries->GetEntries() << endl;
   float VertexZ=event->GetVertexZ();
   cout<<"Vertex z:"<<VertexZ<<endl;

   for(int glcnt=0;glcnt<primaries->GetEntries();glcnt++)
   {
    cout<<"pt "<<((RTrack*)primaries->At(glcnt))->GetPt()<<endl;
   }
   hVz->Fill(VertexZ);

   event->ClearTracks();
  }

  cout << "llop finished!"<<endl;

----------------------------------------------------------------------------


The application crashes after the first event:

----------------------------------------------------------------------------
[play10] ~/<3>RICHAna/root/bin/L3RICHTriggerEfficiency/>
./L3RICHTriggerEfficiency testfiles.txt histo.root
dir:testfiles.txt root:histo.root
add 0: ./testfiles/st_physics_2318025_raw_0001.tree.root
add 1: ./testfiles/st_physics_2318025_raw_0002.tree.root
add 2: ./testfiles/st_physics_2318025_raw_0003.tree.root
add 3: ./testfiles/st_physics_2318025_raw_0004.tree.root
add 4: ./testfiles/st_physics_2318025_raw_0005.tree.root
add 5: ./testfiles/st_physics_2318025_raw_0006.tree.root
add 6: ./testfiles/st_physics_2318025_raw_0007.tree.root
add 7: ./testfiles/st_physics_2318025_raw_0008.tree.root
add 8: ./testfiles/st_physics_2318025_raw_0009.tree.root
 found 9 datafiles
Tree has:619
Tree -> Event:0
primaries:6
Vertex z:-19.1568
pt 0.668843
pt 0.546642
pt 1.2964
pt 0.682589
pt 2.09051
pt 0.755654
Tree -> Event:1
primaries:5
Vertex z:6.6122
pt 1.30538
pt 0.619923
pt 0.658819
pt 0.937802
pt 0.784645
Tree -> Event:2

......
Tree -> Event:71

 *** Break *** segmentation violation
Abort
[play10] ~/<3>RICHAna/root/bin/L3RICHTriggerEfficiency/>
----------------------------------------------------------------------------

You can find the main.C at:
http://www.star.bnl.gov/~jberger/tmp/RICHAna/root/bin/L3RICHTriggerEfficiency/

and the libs at:
http://www.star.bnl.gov/~jberger/tmp/RICHAna/root/lib/RICHAnaTree/

the events:
http://www.star.bnl.gov/~jberger/tmp/RICHAna/root/bin/L3RICHTriggerEfficiency/testfiles/*.root

The events have been created with:
http://www.star.bnl.gov/~jberger/tmp/RICHAna/v2P02gc/RICHAna/StRoot/StRichSpectraTupMaker/StRichSpectraTupMaker.cxx,
StRichSpectraTupMaker.h


Thanks, Jens.


----------------------------------------------------------------------
Jens Berger                  email IKF : jberger@ikf.uni-frankfurt.de
                             email BNL : jberger@bnl.gov
----------------------------------------------------------------------
Institut Kernphysik Frankfurt (IKF):
August-Euler-Str. 06                 office phone: +49-(0)69-798-24254
60486 Frankfurt/Main FRG             office fax  : +49-(0)69-798-24212
----------------------------------------------------------------------
Brookhaven National Laboratory (BNL):
Physics Department
c/o STAR Group
Building 510A                        office phone: +1-(1)631-344-8336
Upton, New York 11973                office fax  : +1-(1)631-344-4206
----------------------------------------------------------------------

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