Hi Ilia, Most of the time, one loops sequentially on the ntuple entries. However a TNtuple, TTree allows direct access to any entry. You can design an algorithm where you compute randomly the entry number to be used or a set of random entries in your loop where you want to mix the entries. Rene Brun Ilia Ravinovich wrote: > > Hi experts, > > I have a created root N-tuple and and I have to calculate some variable > using variables from mixed entries in the N-tuple. How I can do it in the > following loop or using some different way ... > > Int_t nentries = (Int_t)ntuple_pair->GetEntries(); > > cout << " Entries= " << nentries << endl; > > for (Int_t i=0;i<nentries;i++) { > ntuple_pair->GetEntry(i); > } > > Thanks, > > Ilia > > ************************************************************************ > * * > * Ilia Ravinovich * > * Department of Particle Physics PPE Division * > * Weizmann Institute of Science Bld 892, 1D-015 * > * Rehovot 76100 CERN, 1211 Geneva * > * ISRAEL Switzerland * > * * > * PHONE : 972 8 9343187 41 22 7676437 * > * FAX : 972 8 9466253 41 22 7677910 * > * E-mail: Ilia.Ravinovich@weizmann.ac.il Ilia.Ravinovich@cern.ch * > * * > ************************************************************************
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