Hi,
You could use TTree::SetBranchStatus to disable each of the branches
that you not reading. Alternatively, if you have a proper prointer to the
needed branch (See for example the result TTree::MakeSelector or
TTree::MakeClass).
You just read those branches.
Cheers,
Philippe
-----Original Message-----
From: owner-roottalk_at_pcroot.cern.ch [mailto:owner-roottalk_at_pcroot.cern.ch]
On Behalf Of Boris Skorodumov
Sent: Wednesday, July 19, 2006 2:38 AM
To: RootTalk
Subject: [ROOT] Filling a calibrated histogram
Hello !
I am always using the same technique when i would like to get events(channels) from the tree and project them into calibrated histogram (energy).
This is just an short example:
......
f1 = new TFile(fp,"READ");
t = (TTree*)f1->Get("t"); t -> SetBranchAddress("var1", &var1); t -> SetBranchAddress("var2", &var2);
TH2D *energy = new TH2D("energy","",bin1,0,emax1,bin2,0,emax2); Int_t nevent = t -> GetEntries();
for (Int_t i = 0; i < nevent; i++) {
t -> GetEvent(i);
dE = some_number1*(de-0.5+gRandom->Rndm()) + some_number2; E = some_number3*(e-0.5+gRandom->Rndm()) + some_number4; Et = dE + E;
I am wondering, what other methods might be in use to make it even more easy to carry out ? Or maybe method to make it more efficient ?
Thank you,
Boris.
-- ____________________________________________________________________ Boris Skorodumov Office: (574) 631-3148 Physics Department Lab: (574) 631-7716 University of Notre Dame Fax: (574) 631-5952 Notre Dame, In, 46556 Web: http://www.nd.edu/~bskorodo ____________________________________________________________________Received on Wed Jul 19 2006 - 19:17:16 MEST
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