Tree splitter macro problem

ROOT
1

Hello everybody. I found online a macro that splits a given tree with N entries into two identical ones with N/2 entries each. A year ago I used it without any problems but now I don’t seem to get it working.

the macro is:
void splitter(TFile *full_file){

      TTree* full_tree = full_file->Get("mytreecrrct");

      string full_file_name = full_file->GetName();
      int lastindex = full_file_name.find_last_of(".");
      TString rawname = full_file_name.substr(0, lastindex);

      half1_file_name = rawname+"_half1.root";
      half2_file_name = rawname+"_half2.root";

      TFile* half1_file = new TFile(half1_file_name, "RECREATE");
      TTree* half1_tree = full_tree->CloneTree(0);

      TFile* half2_file = new TFile(half2_file_name, "RECREATE");
      TTree* half2_tree = full_tree->CloneTree(0);

      TRandom *r3 = new TRandom3();

      for (int i=0; i<full_tree->GetEntries(); i++){
        full_tree->GetEntry(i);
        Double_t rndm = r3->Rndm();

        if (rndm < 0.5) {
          half1_tree->Fill();
        }
        else {
          half2_tree->Fill();
        }
      }
      half1_file->Write();
      half2_file->Write();

      cout << full_file_name << " entries " << full_tree->GetEntries() << endl;
      cout << half1_file_name << " entries " << half1_tree->GetEntries() << endl;
      cout << half2_file_name << " entries " << half2_tree->GetEntries() << endl;
      cout << "1+2 entries: " << half1_tree->GetEntries() + half2_tree->GetEntries() << endl;
      cout << " " << endl;
    }

void tree_splitter() {

          // had
   TFile* full_file_correctsol_had = new TFile("/afs/cern.ch/work/g/gbillis/TMVA/crrct_sol_total.root","READ");
   splitter(full_file_correctsol_had);

 }

and the output when I compile it in ROOT is :

/afs/cern.ch/work/g/gbillis/TMVA/./tree_splitter.C:26:11: error: cannot initialize a variable of type ‘TTree *’ with
an rvalue of type 'TObject '
TTree full_tree = full_file->Get(“mytreecrrct”);
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/afs/cern.ch/work/g/gbillis/TMVA/./tree_splitter.C:32:4: error: use of undeclared identifier 'half1_file_name’
half1_file_name = rawname+"_half1.root";
^
/afs/cern.ch/work/g/gbillis/TMVA/./tree_splitter.C:33:4: error: use of undeclared identifier 'half2_file_name’
half2_file_name = rawname+"_half2.root";
^
/afs/cern.ch/work/g/gbillis/TMVA/./tree_splitter.C:35:34: error: use of undeclared identifier 'half1_file_name’
TFile* half1_file = new TFile(half1_file_name, “RECREATE”);
^
/afs/cern.ch/work/g/gbillis/TMVA/./tree_splitter.C:38:34: error: use of undeclared identifier 'half2_file_name’
TFile* half2_file = new TFile(half2_file_name, “RECREATE”);
^
/afs/cern.ch/work/g/gbillis/TMVA/./tree_splitter.C:58:12: error: use of undeclared identifier 'half1_file_name’
cout << half1_file_name << " entries " << half1_tree->GetEntries() << endl;
^
/afs/cern.ch/work/g/gbillis/TMVA/./tree_splitter.C:59:12: error: use of undeclared identifier 'half2_file_name’
cout << half2_file_name << " entries " << half2_tree->GetEntries() << endl;

Can anyone help?

2

Try casting the tree, like

TTree *full_tree = (TTree *) full_file->Get(“mytreecrrct”);
3 
TTree *full_tree; full_file->GetObject("mytreecrrct", full_tree);
if (!full_tree) std::cout << "NO mytreecrrct!" << std::endl;
4

FYI:

5

Thank you everybody, the solution was that I missed the (TTree*). Now a new issue occurred. I have a tree that has 36965800 events and when I try to split it, the resulting files come with 2 trees names mytreewrng;27 and mytreewrng;28. The same thing did not happen when I split a much smaller file of 1000 events…anyone has any idea what is happening? I am mentioning the number of events because it is the only difference in the two files.

cheers
George

6