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// script illustrating the use of a Tree using the JetEvent class.
// The JetEvent class has several collections (TClonesArray)
// and other collections (TRefArray) referencing objects
// in the TClonesArrays.
// The JetEvent class is in $ROOTSYS/tutorials/JetEvent.h,cxx
// to execute the script, do
// .x jets.C
//
//Author: Rene Brun
#include "TFile.h"
#include "TTree.h"
#include "TRandom.h"
#include "TROOT.h"
#include "TSystem.h"
#ifdef __CINT__
#else
#include "JetEvent.h"
#endif
#include "Riostream.h"
void write(Int_t nev=100) {
//write nev Jet events
TFile f("JetEvent.root","recreate");
TTree *T = new TTree("T","Event example with Jets");
JetEvent *event = new JetEvent;
T->Branch("event","JetEvent",&event,8000,2);
for (Int_t ev=0;ev<nev;ev++) {
event->Build();
T->Fill();
}
T->Print();
T->Write();
}
void read() {
//read the JetEvent file
TFile f("JetEvent.root");
TTree *T = (TTree*)f.Get("T");
JetEvent *event = 0;
T->SetBranchAddress("event", &event);
Long64_t nentries = T->GetEntries();
for (Long64_t ev=0;ev<nentries;ev++) {
T->GetEntry(ev);
if (ev) continue; //dump first event only
cout << " Event: "<< ev
<< " Jets: " << event->GetNjet()
<< " Tracks: " << event->GetNtrack()
<< " Hits A: " << event->GetNhitA()
<< " Hits B: " << event->GetNhitB() << endl;
}
}
void pileup(Int_t nev=200) {
//make nev pilepup events, each build with LOOPMAX events selected
//randomly among the nentries
TFile f("JetEvent.root");
TTree *T = (TTree*)f.Get("T");
// Long64_t nentries = T->GetEntries();
const Int_t LOOPMAX=10;
JetEvent *events[LOOPMAX];
Int_t loop;
for (loop=0;loop<LOOPMAX;loop++) events[loop] = 0;
for (Long64_t ev=0;ev<nev;ev++) {
if (ev%10 == 0) printf("building pileup: %lld\n",ev);
for (loop=0;loop<LOOPMAX;loop++) {
Int_t rev = gRandom->Uniform(LOOPMAX);
T->SetBranchAddress("event", &events[loop]);
T->GetEntry(rev);
}
}
}
void jets(Int_t nev=100, Int_t npileup=200) {
gSystem->Load("libPhysics");
gROOT->ProcessLine(".L $ROOTSYS/tutorials/tree/JetEvent.cxx+");
write(nev);
read();
pileup(npileup);
}
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