#include "fastjet/PseudoJet.hh"
#include "fastjet/ClusterSequenceArea.hh"
#include <iostream>
#include <sstream>
#include <vector>
Include dependency graph for fastjet_subtraction.cc:
Go to the source code of this file.
Functions | |
void | print_jets (const fastjet::ClusterSequenceAreaBase &clust_seq, const vector< fastjet::PseudoJet > &unsorted_jets) |
a function that pretty prints a list of jets, and performs the subtraction in two different ways, using a generic ClusterSequenceAreaBase type object. | |
int | main (int argc, char **argv) |
an example program showing how to use fastjet |
int main | ( | int | argc, | |
char ** | argv | |||
) |
an example program showing how to use fastjet
Definition at line 61 of file fastjet_subtraction.cc.
References fastjet::Best, fastjet::ClusterSequence::inclusive_jets(), fastjet::kt_algorithm, print_jets(), fastjet::PseudoJet::rap(), fastjet::PseudoJet::set_user_index(), and fastjet::ClusterSequence::strategy_string().
00061 { 00062 00063 // since we use here simulated data we can split the hard event 00064 // from the full (i.e. with pileup added) one 00065 vector<fastjet::PseudoJet> hard_event, full_event; 00066 00067 // maximum rapidity that we accept for the input particles 00068 double etamax = 6.0; 00069 00070 // read in input particles. Keep the hard event generated by PYTHIA 00071 // separated from the full event, so as to be able to gauge the 00072 // "goodness" of the subtraction from the full event which also 00073 // includes pileup 00074 string line; 00075 int nsub = 0; 00076 while (getline(cin, line)) { 00077 istringstream linestream(line); 00078 // take substrings to avoid problems when there are extra "pollution" 00079 // characters (e.g. line-feed). 00080 if (line.substr(0,4) == "#END") {break;} 00081 if (line.substr(0,9) == "#SUBSTART") { 00082 // if more sub events follow, make copy of hard one here 00083 if (nsub == 1) hard_event = full_event; 00084 nsub += 1; 00085 } 00086 if (line.substr(0,1) == "#") {continue;} 00087 valarray<double> fourvec(4); 00088 linestream >> fourvec[0] >> fourvec[1] >> fourvec[2] >> fourvec[3]; 00089 fastjet::PseudoJet psjet(fourvec); 00090 psjet.set_user_index(0); 00091 // push event onto back of full_event vector 00092 if (abs(psjet.rap()) < etamax) {full_event.push_back(psjet);} 00093 } 00094 00095 // if we have read in only one event, copy it across here... 00096 if (nsub == 1) hard_event = full_event; 00097 00098 // if there was nothing in the event 00099 if (nsub == 0) { 00100 cerr << "Error: read empty event\n"; 00101 exit(-1); 00102 } 00103 00104 00105 // create an object that represents your choice of jet algorithm and 00106 // the associated parameters 00107 double R = 0.7; 00108 fastjet::Strategy strategy = fastjet::Best; 00109 fastjet::JetDefinition jet_def(fastjet::kt_algorithm, R, strategy); 00110 //fastjet::JetDefinition jet_def(fastjet::cambridge_algorithm, R, strategy); 00111 //fastjet::JetDefinition jet_def(fastjet::antikt_algorithm, R, strategy); 00112 00113 // create an object that specifies how we to define the (active) area 00114 double ghost_etamax = 6.0; 00115 int active_area_repeats = 1; 00116 double ghost_area = 0.01; 00117 fastjet::ActiveAreaSpec area_spec(ghost_etamax, active_area_repeats, 00118 ghost_area); 00119 fastjet::AreaDefinition area_def(area_spec); 00120 //fastjet::AreaDefinition area_def(fastjet::VoronoiAreaSpec(1.0)); 00121 00122 // run the jet clustering with the above jet definition. hard event first 00123 fastjet::ClusterSequenceArea clust_seq(hard_event, jet_def, area_def); 00124 //fastjet::ClusterSequencePassiveArea clust_seq(hard_event, jet_def); 00125 00126 00127 // extract the inclusive jets with pt > 5 GeV, sorted by pt 00128 double ptmin = 5.0; 00129 vector<fastjet::PseudoJet> inclusive_jets = clust_seq.inclusive_jets(ptmin); 00130 00131 // print them out 00132 cout << "" <<endl; 00133 cout << "Hard event only"<<endl; 00134 cout << "Number of input particles: "<<hard_event.size()<<endl; 00135 cout << "Strategy used: "<<clust_seq.strategy_string()<<endl; 00136 cout << "Printing inclusive jets with pt > "<< ptmin<<" GeV\n"; 00137 cout << "---------------------------------------\n"; 00138 print_jets(clust_seq, inclusive_jets); 00139 cout << endl; 00140 00141 00142 // repeat everything on the full event 00143 00144 // run the jet clustering with the above jet definition 00145 //fastjet::ClusterSequenceActiveArea clust_seq_full(full_event, jet_def, area_spec); 00146 fastjet::ClusterSequenceArea clust_seq_full(full_event, jet_def, area_def); 00147 //fastjet::ClusterSequencePassiveArea clust_seq_full(full_event, jet_def,0.9); 00148 00149 // extract the inclusive jets with pt > 20 GeV, sorted by pt 00150 ptmin = 20.0; 00151 inclusive_jets = clust_seq_full.inclusive_jets(ptmin); 00152 00153 // print them out 00154 cout << "Full event, with pileup, and its subtraction"<<endl; 00155 cout << "Number of input particles: "<<full_event.size()<<endl; 00156 cout << "Strategy used: "<<clust_seq_full.strategy_string()<<endl; 00157 cout << "Printing inclusive jets with pt > "<< ptmin<<" GeV (before subtraction)\n"; 00158 cout << "---------------------------------------\n"; 00159 print_jets(clust_seq_full, inclusive_jets); 00160 cout << endl; 00161 00162 00163 }
void print_jets | ( | const fastjet::ClusterSequenceAreaBase & | clust_seq, | |
const vector< fastjet::PseudoJet > & | unsorted_jets | |||
) |
a function that pretty prints a list of jets, and performs the subtraction in two different ways, using a generic ClusterSequenceAreaBase type object.