[ROOT] Event list

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Using : 3.03/02, Compiled for solarisCC5, Solaris 5.9

Hi all,

I would like some some help with using TEventList and TChain.

Skeleton of code to create list :


int MakeList()
{
  //Compressed Scanning Data event class
  TChain *chain = new TChain("Crystal B");   //Chain the tree "Crystal B"
  
  chain->Add("/home/crash6/gamma/karl/ScanB1.root");
  if (chain == 0) return 0;
  chain->Add("/home/crash6/gamma/karl/ScanB2.root");
  if (chain == 0) return 0;

  Int_t nevents = Int_t(chain->GetEntries());
  printf("\n %d events",nevents);

  //===============================================
  // Specify address where to read the event object
  // The event was stored in a branch called "Prototype"
  //===============================================
  
  //object must be created before setting the branch address
  ProtoExoScan *Data = new ProtoExoScan();
  
  //Super branch
  chain->SetBranchAddress("ProtoType", &Data);

  //Make an event list and file to store it
  Int_t comp = 5;        // by default all files compressed
  TEventList *elist =
    new TEventList("elist","Events with # segments with E > THRESH = 1",5000);
  TFile *efile = new TFile("elist2.root","RECREATE",
			   "nSegs = 1 event list");
  efile->SetCompressionLevel(comp);
  
  //Loop over all chained events.....
  for (nGood = jentry=0; jentry < nevents; jentry++) {
    ientry = chain->LoadTree(jentry);//ientry :entry number in the current file
    
    //////////////////////////////////////////////////////
    //Examine ALL Data
    nb = chain->GetEntry(jentry); nbytes += nb;
    Data->GetData(&x, &y, &TrigE, &TrigT, &segE[0], &segT[0], &pulse[0][0]);
    
    if ( ((TrigE >= 6337) && (TrigE <= 6355)) ||
	 ((TrigE >=  550) && (TrigE <=  565)) ) {
	 
	elist->Enter(chain->GetChainEntryNumber(ientry));
    }	   
  elist->Write();
  efile->Close();
  return jentry;
}

======================================================================

This appears to work in the simple case :

int CheckList()
{
  //read in created list
  TFile *efile = new TFile("elist2.root","READ");
  TEventList *elist = (TEventList*) efile->Get("elist");

  //TEventList elist = efile->Get("elist");
  if (elist) elist->SetDirectory(0);
  
  nevents = Int_t(elist->GetN());
  printf("\n %d events in list",nevents);
  
  //Loop over all chained events.....
  for (jentry=0; jentry < 20; jentry++) {
    
    entry = elist->GetEntry(jentry);
    printf("\n %d %d",jentry,entry);

  }
  return jentry;
}

========================================================================

But I can't get it to work with a Chain : The following
hangs up at the end of the first root file.....

Suggestions ?

int ReadTree()
{
#ifdef __CINT__
  //Load class if needed
  if (!TClassTable::GetDict("ProtoExoScan")) {
    gSystem.Load("libProtoExoScan.so");
  }
#endif
  gROOT->SetBatch(kTRUE);
  
  //read in created list
  TFile *efile = new TFile("elist2.root","READ");
  TEventList *elist = (TEventList*) efile->Get("elist");
  //TEventList elist = efile->Get("elist");
  if (elist) elist->SetDirectory(0);

  //Compressed Scanning Data event class
  TChain *chain = new TChain("Crystal B");   //Chain the tree "Crystal B"
  
  chain->Add("/home/crash6/gamma/karl/ScanB1.root");
  if (chain == 0) return 0;
  chain->Add("/home/crash6/gamma/karl/ScanB2.root");
  if (chain == 0) return 0;
  chain->Add("/home/crash6/gamma/karl/ScanB3.root");
  if (chain == 0) return 0;
  chain->Add("/home/crash6/gamma/karl/ScanB4.root");
  if (chain == 0) return 0;

  Int_t nevents = Int_t(chain->GetEntries());
  printf("\n %d events in total",nevents);

  //chain->SetEventList(elist);
  
  nevents = Int_t(elist->GetN());
  printf("\n %d events in list",nevents);

  //===============================================
  // Specify address where to read the event object
  // The event was stored in a branch called "Prototype"
  //===============================================
  
  //object must be created before setting the branch address
  ProtoExoScan *Data = new ProtoExoScan();
  
  //Super branch : CompData
  chain->SetBranchAddress("ProtoType", &Data);

  Int_t entry, jentry, ientry;
  Int_t nbytes = 0;
  Int_t nb = 0;


  //Loop over all chained events.....
  for (nGood = jentry=0; jentry < nevents; jentry++) {
    ientry = chain->LoadTree(jentry);
    
    //////////////////////////////////////////////////////
    //Examine ALL Data
    entry = elist->GetEntry(jentry);

    nb = chain->GetEntry(entry); nbytes += nb;
    Data->GetData(&x, &y, &TrigE, &TrigT, &segE[0], &segT[0], &pulse[0][0]);
    
    //assign position...
    Data->GetPosition(&x, &y);
    hPosition->Fill(x,y);
    :
    blah blah blah
    :
    }
  }
  return jentry;
}


Cheers,

Karl
==========================================================================

CEA Saclay, DAPNIA/SPhN                Phone  : (33) 01 69 08 7553
Bat 703 - l'Orme des Merisiers         Fax    : (33) 01 69 08 7584
F-91191 Gif-sur-Yvette                 E-mail :  khauschild@cea.fr
France                                           karl_hauschild@yahoo.co.uk
                                       WWW: http://www-dapnia.cea.fr/Sphn

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