TChain vs. TCastorFile and TTree

ROOT
1

Hi,
I’m trying to plot the same variable into a new histo, Draw(“variable>>histo”), opening the same file using TChain or TCastorFile:

void comp() {

TH1D *data, *mc;
TChain ss3(“Tree”);
TCastorFile *pipi0;
TTree *pipi0_tree;

TH1D *data = new TH1D(“data”, “data”, 50, .13, .14);
TH1D *mc = new TH1D(“mc”, “mc”, 50, .13, .14);

TCanvas *c1 = new TCanvas(“c1”, “c1”, 700, 700);
c1->Divide(2,2);

ss3.Add("/castor/cern.ch/user/b/bifani/pipi0/scmp/SS3-40/0.root");
c1_1->cd();
ss3.Draw(“mgg>>data”);

pipi0 = new TCastorFile("/castor/cern.ch/user/b/bifani/pipi0/scmp/SS3-40/0.root");
pipi0_tree = (TTree*) pipi0->Get(“Tree”);
c1_2->cd();
pipi0_tree->Draw(“mgg>>mc”);

c1_3->cd();
data->Draw();
c1_4->cd();
mc->Draw();

}

DATA histo filled with TChain opened file is ok.
MC histo filled with TCastorFile opened file is empty.

What is wrong in that macro?

s.

2

Could you change your macro as shown below

[code]void comp() {

TH1D *data, *mc;
TChain ss3(“Tree”);
TCastorFile *pipi0;
TTree *pipi0_tree;

TCanvas *c1 = new TCanvas(“c1”, “c1”, 700, 700);
c1->Divide(2,2);

ss3.Add("/castor/cern.ch/user/b/bifani/pipi0/scmp/SS3-40/0.root");
c1_1->cd();
TH1D *data = new TH1D(“data”, “data”, 50, .13, .14);
ss3.Draw(“mgg>>data”);

pipi0 = new TCastorFile("/castor/cern.ch/user/b/bifani/pipi0/scmp/SS3-40/0.root");
pipi0_tree = (TTree*) pipi0->Get(“Tree”);
c1_2->cd();
TH1D *mc = new TH1D(“mc”, “mc”, 50, .13, .14);
//TTree::Draw will take the “mc” histo in the current dir
pipi0_tree->Draw(“mgg>>mc”);

c1_3->cd();
data->Draw();
c1_4->cd();
mc->Draw();

}
[/code]
Rene