Hello Rooters
I know this topic has already been discussed her but somehow I am missing
a point.
I have a tree which contains c-structures and TLorentzVectors. I would
like to copy all branches of the tree to another one but only a few
selected entries.
So, based on examples in the tutorials, I did:
gSystem->Load("libPhysics");
TFile* f = new TFile("oldfile.root");
TTree* tree_old = (TTree*) f->Get("tree");
info = new info_t; // info_t is a c-structure
kine = new kine_t; // kine_t is a c-structure
tdist = new tdist_t; // tdist_t is a c-structure
TLorentzVector* v4P1 = new TLorentzVector;
TLorentzVector* v4P2 = new TLorentzVector;
tree_old->SetBranchAddress("info", &info);
tree_old->SetBranchAddress("kine", &kine);
tree_old->SetBranchAddress("tdist", &tdist);
tree_old->SetBranchAddress("p1", &v4P1);
tree_old->SetBranchAddress("p2", &v4P2);
tree_old->SetBranchStatus("*", 1);
TFile *newfile = new TFile("newfile.root","recreate");
TTree *newtree = tree_old->CopyTree("complicated cut");
newtree->SetName("tree");
newfile->Write();
newfile->Close();
This fails! I compared the values in the c-structures in the old (using
the cut) and new tree, they are identical, so that's good. The
number of evens in the old tree after cut is the same than the
number of events in the new tree. However the components of the
TLorentzVectors are differents. I built the old tree in non-split mode for
the TLorentzVector using ROOT 3.00/06 on Linux Red Hat 6.2 and I am
trying to make the subselection using ROOT 3.02/00 on the same machine,
same OS.
What am I doing wrong?
Thanks
Matthieu Guillo
University of South Carolina
Thomas Jefferson National Laboratory
Office 71 trailer 16
Phone: 757-269-5551
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