{
  std::cout<< "Entries:" <<  ptree->GetEntries()<< std::endl;
  ptree->BuildIndex("time");
  TTreeIndex *I=(TTreeIndex*)ptree->GetTreeIndex(); // get the tree index
  Long64_t* index=I->GetIndex(); //create an array of entries in sorted order

  TLeaf* time=ptree->GetBranch("event")->GetLeaf("time");
  for (int i=0;i<ptree->GetEntries();i++){
    ptree->GetEntry(index[i]); 
    std::cout <<time->GetValue() << std::endl; //print the time:  should be sorted
  }
}