Problem using TChain

ROOT
1

Hi,

I need to read more than one data file (all of them with the same structure), so I would like to use TChain, but I have some problems.
What I usually do with only one file is:

TFile fIn = TFile::Open(“rfio:/castor/file.root”);
TTree * events = dynamic_cast<TTree>( fIn->Get( “Events” ) );
TBranch * solsBranch;
solsBranch = events->GetBranch(“TtSemiEvtSolutions_solutions__TtEventReco.obj” );
vector sols;
solsBranch -> SetAddress( & sols );

and then loop over the events:

int nev = events->GetEntries();
for( int ev = 0; ev < nev; ++ ev ) {
solsBranch -> GetEntry( ev );
cout << “sols.size” << " " << sols.size() << endl;
}

Now I tried to translate the previous commands using TChain, but the sols vector is always empty (sols.size=0). This is what I wrote:

TChain *fIn = new TChain(“Events”);
fIn->Add(“rfio:/castor/file.root”);
vector sols;
fIn->SetBranchAddress( “TtSemiEvtSolutions_solutions__TtEventReco.obj”, & sols );
int nev = fIn->GetEntries();
for( int ev = 0; ev < nev; ++ ev ) {
fIn -> GetEntry( ev );
cout << “sols.size” << " " << sols.size() << endl;
}

Any idea of what I am doing wrong?
I also tried using
fIn -> SetBranchStatus("*", 0);
fIn -> SetBranchStatus(“TtSemiEvtSolutions_solutions__TtEventReco.obj”, 1);
after SetBranchAddress, without success.
Ah, I am using Root 5.12.00e on a SLC3 machine.

Thanks a lot for any hint.
Cheers,
Laura

2

Hi,

There are some issue with setting the address of a sub-object (your case) where the hand coded address is over-written during the loading of a new file of TChain.

To work around the problem, you need to do TBranch *solsBranch; Int_t treenumber = -1; for( int ev = 0; ev < nev; ++ ev ) { Long64_t local = fIn -> LoadEntry( ev ); if (treenumber != fin->GetTreeNumber()) { fIn->SetBranchAddress( "TtSemiEvtSolutions_solutions__TtEventReco.obj", & sols, solsBranch ); treenumber = fin->GetTreeNumber(); } solsBranch -> GetEntry( local ); cout << "sols.size" << " " << sols.size() << endl; }

Cheers,
Philippe