FastJet 3.0.2
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00001 //---------------------------------------------------------------------- 00002 /// \file 00003 /// \page Example05 05 - using e+e- algorithms 00004 /// 00005 /// illustrate the use of e^+ e^- algorithms 00006 /// 00007 /// They mostly differ from the pp algorithm by the fact that rather 00008 /// than using a radius parameter and inclusive jets, they use 00009 /// exclusive jets in one of the following ways: 00010 /// - a fixed number of them 00011 /// - with a dcut 00012 /// - with a ycut 00013 /// 00014 /// Note that natively, FastJet includes the kt (ee_kt_algorithm) and 00015 /// genkt (ee_genkt_algorithm) algorithms. Others (like Cambridge for 00016 /// e+ e-, Jade or SISCone in spherical coordinates) are available as 00017 /// plugins (see 03-plugin.cc) 00018 /// 00019 /// run it with : ./05-eplus_eminus < data/single-ee-event.dat 00020 /// 00021 /// Source code: 05-eplus_eminus.cc 00022 //---------------------------------------------------------------------- 00023 00024 //STARTHEADER 00025 // $Id: 05-eplus_eminus.cc 2684 2011-11-14 07:41:44Z soyez $ 00026 // 00027 // Copyright (c) 2005-2011, Matteo Cacciari, Gavin P. Salam and Gregory Soyez 00028 // 00029 //---------------------------------------------------------------------- 00030 // This file is part of FastJet. 00031 // 00032 // FastJet is free software; you can redistribute it and/or modify 00033 // it under the terms of the GNU General Public License as published by 00034 // the Free Software Foundation; either version 2 of the License, or 00035 // (at your option) any later version. 00036 // 00037 // The algorithms that underlie FastJet have required considerable 00038 // development and are described in hep-ph/0512210. If you use 00039 // FastJet as part of work towards a scientific publication, please 00040 // include a citation to the FastJet paper. 00041 // 00042 // FastJet is distributed in the hope that it will be useful, 00043 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00044 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00045 // GNU General Public License for more details. 00046 // 00047 // You should have received a copy of the GNU General Public License 00048 // along with FastJet. If not, see <http://www.gnu.org/licenses/>. 00049 //---------------------------------------------------------------------- 00050 //ENDHEADER 00051 00052 #include "fastjet/ClusterSequence.hh" 00053 #include <iostream> // needed for io 00054 #include <cstdio> // needed for io 00055 00056 using namespace std; 00057 00058 /// an example program showing how to use fastjet 00059 int main(){ 00060 00061 // read in input particles 00062 //---------------------------------------------------------- 00063 vector<fastjet::PseudoJet> input_particles; 00064 00065 double px, py , pz, E; 00066 while (cin >> px >> py >> pz >> E) { 00067 // create a fastjet::PseudoJet with these components and put it onto 00068 // back of the input_particles vector 00069 input_particles.push_back(fastjet::PseudoJet(px,py,pz,E)); 00070 } 00071 00072 00073 // create a jet definition for the kt algorithm (note that one 00074 // should not specify an R value here) 00075 //---------------------------------------------------------- 00076 fastjet::JetDefinition jet_def(fastjet::ee_kt_algorithm); 00077 00078 // run the jet clustering with the above jet definition 00079 //---------------------------------------------------------- 00080 fastjet::ClusterSequence clust_seq(input_particles, jet_def); 00081 00082 // get 3 exclusive jets 00083 //---------------------------------------------------------- 00084 int n = 3; 00085 vector<fastjet::PseudoJet> exclusive_jets = clust_seq.exclusive_jets(n); 00086 00087 00088 // tell the user what was done 00089 // - the description of the algorithm used 00090 // - extract the inclusive jets with pt > 5 GeV 00091 // show the output as 00092 // {index, rap, phi, pt, number of constituents} 00093 //---------------------------------------------------------- 00094 cout << "Ran " << jet_def.description() << endl; 00095 00096 // label the columns 00097 printf("%5s %15s\n","jet #", "E"); 00098 00099 // print out the details for each jet 00100 for (unsigned int i = 0; i < exclusive_jets.size(); i++) { 00101 printf("%5u %15.8f\n", 00102 i, exclusive_jets[i].perp()); 00103 } 00104 00105 return 0; 00106 }