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// $Id: example.cc 893 2015-11-06 09:10:35Z berta $
//
//----------------------------------------------------------------------
// Example on how to use this contribution
//
// run it with
// ./example < ../data/Pythia-Zp2jets-lhc-pileup-1ev.dat
//----------------------------------------------------------------------
//
//----------------------------------------------------------------------
// This file is part of FastJet contrib.
//
// It is free software; you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the
// Free Software Foundation; either version 2 of the License, or (at
// your option) any later version.
//
// It is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
// License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this code. If not, see <http://www.gnu.org/licenses/>.
//----------------------------------------------------------------------
#include "functions.hh"
//----------------------------------------------------------------------
int main(){
//----------------------------------------------------------
// read in input particles
vector<PseudoJet> hard_event, full_event;
read_event(hard_event, full_event);
// keep the particles up to 4 units in rapidity
hard_event = SelectorAbsRapMax(4.0)(hard_event);
full_event = SelectorAbsRapMax(4.0)(full_event);
cout << "# read an event with " << hard_event.size() << " signal particles and " << full_event.size() - hard_event.size() << " background particles with rapidity |y|<4" << endl;
// do the clustering with ghosts and get the jets
//----------------------------------------------------------
JetDefinition jet_def(antikt_algorithm, 0.7);
double ghost_area=0.01; // the density of ghosts can be changed through this variable
AreaDefinition area_def(active_area_explicit_ghosts,GhostedAreaSpec(4.0,1,ghost_area)); // in this step, the ghosts are added among the constituents of the jets
ClusterSequenceArea clust_seq_hard(hard_event, jet_def, area_def);
ClusterSequenceArea clust_seq_full(full_event, jet_def, area_def);
Selector sel_jets = SelectorNHardest(2) * SelectorAbsRapMax(3.0);
vector<PseudoJet> hard_jets = sel_jets(clust_seq_hard.inclusive_jets());
vector<PseudoJet> full_jets = sel_jets(clust_seq_full.inclusive_jets());
// create what we need for the background estimation
//----------------------------------------------------------
JetDefinition jet_def_for_rho(kt_algorithm, 0.4);
Selector rho_range = SelectorAbsRapMax(3.0);
ClusterSequenceArea clust_seq_rho(full_event, jet_def, area_def);
JetMedianBackgroundEstimator bge_rho(rho_range, jet_def_for_rho, area_def);
BackgroundJetScalarPtDensity *scalarPtDensity=new BackgroundJetScalarPtDensity();
bge_rho.set_jet_density_class(scalarPtDensity); // this changes the computation of pt of patches from vector sum to scalar sum. The scalar sum seems more reasonable.
bge_rho.set_particles(full_event);
// subtractor:
//----------------------------------------------------------
contrib::ConstituentSubtractor subtractor(&bge_rho);
// this sets the same background estimator to be used for deltaMass density, rho_m, as for pt density, rho:
subtractor.set_common_bge_for_rho_and_rhom(true); // for massless input particles it does not make any difference (rho_m is always zero)
cout << subtractor.description() << endl;
// shape variables:
//----------------------------------------------------------
JetWidth width;
// subtract and print the result
//----------------------------------------------------------
cout << setprecision(4);
cout << "# original hard jets" << endl;
for (unsigned int i=0; i<hard_jets.size(); i++){
const PseudoJet &jet = hard_jets[i];
cout << "pt = " << jet.pt()
<< ", rap = " << jet.rap()
<< ", mass = " << jet.m()
<< ", width = " << width(jet) << endl;
}
cout << endl;
cout << "# unsubtracted full jets" << endl;
for (unsigned int i=0; i<full_jets.size(); i++){
const PseudoJet &jet = full_jets[i];
cout << "pt = " << jet.pt()
<< ", rap = " << jet.rap()
<< ", mass = " << jet.m()
<< ", width = " << width(jet) << endl;
}
cout << endl;
cout << "# subtracted full jets" << endl;
for (unsigned int i=0; i<full_jets.size(); i++){
const PseudoJet &jet = full_jets[i];
PseudoJet subtracted_jet = subtractor(jet);
cout << "pt = " << subtracted_jet.pt()
<< ", rap = " << subtracted_jet.rap()
<< ", mass = " << subtracted_jet.m()
<< ", width = " << width(subtracted_jet) << endl;
}
cout << endl;
return 0;
}

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