fastjet_areas.cc File Reference

#include "fastjet/PseudoJet.hh"
#include "fastjet/ClusterSequenceArea.hh"
#include "fastjet/ClusterSequencePassiveArea.hh"
#include "fastjet/config.h"
#include "fastjet/SISConePlugin.hh"
#include <iostream>
#include <sstream>
#include <vector>

Include dependency graph for fastjet_areas.cc:

Go to the source code of this file.

Functions
void	print_jets (const fastjet::ClusterSequenceAreaBase &, const vector< fastjet::PseudoJet > &)
	a function that pretty prints a list of jets
int	main (int argc, char **argv)
	an example program showing how to use fastjet

---

Function Documentation

int main (  int  argc, char **  argv )

an example program showing how to use fastjet Definition at line 67 of file fastjet_areas.cc. References fastjet::Best, fastjet::AreaDefinition::description(), fastjet::JetDefinition::description(), fastjet::ClusterSequence::inclusive_jets(), fastjet::kt_algorithm, fastjet::passive_area, print_jets(), and fastjet::ClusterSequence::strategy_string(). { vector<fastjet::PseudoJet> input_particles; // read in input particles double px, py , pz, E; while (cin >> px >> py >> pz >> E) { // create a fastjet::PseudoJet with these components and put it onto // back of the input_particles vector input_particles.push_back(fastjet::PseudoJet(px,py,pz,E)); } // create an object that represents your choice of jet algorithm, and // the associated parameters double Rparam = 1.0; fastjet::Strategy strategy = fastjet::Best; fastjet::JetDefinition jet_def(fastjet::kt_algorithm, Rparam, strategy); //fastjet::JetDefinition jet_def(fastjet::cambridge_algorithm, Rparam, strategy); //fastjet::JetDefinition jet_def(fastjet::antikt_algorithm, Rparam, strategy); //fastjet::JetDefinition jet_def(new fastjet::SISConePlugin(1.0)); // create an object that specifies how we to define the area fastjet::AreaDefinition area_def; bool use_voronoi = false; if (!use_voronoi) { double ghost_etamax = 7.0; double ghost_area = 0.05; int active_area_repeats = 1; // alternative settings for more precision: // reducing ghost area gives better sensitivity to the exact edges of the jet //double ghost_area = 0.01; // increasing the repeats is useful in sparse events //int active_area_repeats = 100; // now create the object that holds info about ghosts, and from that // get an area definition fastjet::GhostedAreaSpec ghost_spec(ghost_etamax, active_area_repeats, ghost_area); area_def = fastjet::AreaDefinition(fastjet::passive_area,ghost_spec); } else { double effective_Rfact = 1.0; area_def = fastjet::VoronoiAreaSpec(effective_Rfact); } // run the jet clustering with the above jet definition fastjet::ClusterSequenceArea clust_seq(input_particles, jet_def, area_def); // you can also run the individual area classes directly //fastjet::ClusterSequencePassiveArea clust_seq(input_particles, jet_def, // area_def.ghost_spec()); // you may want to find out how much area in a given range (|y|<range) // is empty of real jets (or corresponds to pure "ghost" jets). //double range = 4.0; //cout << clust_seq.empty_area(range) << endl; //cout << clust_seq.n_empty_jets(range) << endl; // tell the user what was done cout << "Jet definition was: " << jet_def.description() << endl; cout << "Area definition was: " << area_def.description() << endl; cout << "Strategy adopted by FastJet was "<< clust_seq.strategy_string()<<endl<<endl; // extract the inclusive jets with pt > 5 GeV, sorted by pt double ptmin = 5.0; vector<fastjet::PseudoJet> inclusive_jets = clust_seq.inclusive_jets(ptmin); // print them out cout << "Printing inclusive jets with pt > "<< ptmin<<" GeV\n"; cout << "---------------------------------------\n"; print_jets(clust_seq, inclusive_jets); cout << endl; cout << "Number of unclustered particles: " << clust_seq.unclustered_particles().size() << endl; }

void print_jets (  const fastjet::ClusterSequenceAreaBase &  , const vector< fastjet::PseudoJet > &  )

a function that pretty prints a list of jets Definition at line 150 of file fastjet_areas.cc. References fastjet::ClusterSequenceAreaBase::area(), fastjet::ClusterSequenceAreaBase::area_error(), and fastjet::sorted_by_pt(). Referenced by main(), and run_jet_finder(). { // sort jets into increasing pt vector<fastjet::PseudoJet> jets = sorted_by_pt(unsorted_jets); printf(" ijet rap phi Pt area +- err\n"); for (size_t j = 0; j < jets.size(); j++) { double area = clust_seq.area(jets[j]); double area_error = clust_seq.area_error(jets[j]); printf("%5u %9.5f %8.5f %10.3f %8.3f +- %6.3f\n",j,jets[j].rap(), jets[j].phi(),jets[j].perp(), area, area_error); } }

---