| 1 | //STARTHEADER
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| 2 | // $Id$
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| 3 | //
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| 4 | // Copyright (c) 2007-2011, Matteo Cacciari, Gavin P. Salam and Gregory Soyez
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| 5 | // Copyright (c) ????-????, CMS [for the iterative-cone code itself]
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| 6 | //
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| 7 | //----------------------------------------------------------------------
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| 8 | // This file is part of FastJet. It contains code that has been
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| 9 | // obtained from the CMS collaboration, revision 1.14 of the
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| 10 | // CMSIterativeConeAlgorithm.cc file in CMSSW, see
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| 11 | // http://cmssw.cvs.cern.ch/cgi-bin/cmssw.cgi/CMSSW/RecoJets/JetAlgorithms/src/CMSIterativeConeAlgorithm.cc?hideattic=0&revision=1.14&view=markup
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| 12 | //
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| 13 | // Permission has been granted by the CMS collaboration to release it
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| 14 | // in FastJet under the terms of the GNU Public License(v2) (see the
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| 15 | // COPYING file in the main FastJet directory for details).
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| 16 | // Changes from the original file are listed below.
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| 17 | //
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| 18 | // FastJet is free software; you can redistribute it and/or modify
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| 19 | // it under the terms of the GNU General Public License as published by
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| 20 | // the Free Software Foundation; either version 2 of the License, or
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| 21 | // (at your option) any later version.
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| 22 | //
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| 23 | // The algorithms that underlie FastJet have required considerable
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| 24 | // development and are described in hep-ph/0512210. If you use
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| 25 | // FastJet as part of work towards a scientific publication, please
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| 26 | // include a citation to the FastJet paper.
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| 27 | //
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| 28 | // FastJet is distributed in the hope that it will be useful,
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| 29 | // but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 30 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 31 | // GNU General Public License for more details.
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| 32 | //
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| 33 | // You should have received a copy of the GNU General Public License
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| 34 | // along with FastJet. If not, see <http://www.gnu.org/licenses/>.
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| 35 | //----------------------------------------------------------------------
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| 36 | //ENDHEADER
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| 37 |
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| 38 | // List of changes compared to the original CMS code (revision 1.14 of
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| 39 | // CMSIterativeConeAlgorithm.cc)
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| 40 | //
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| 41 | // 2009-05-10 Gavin Salam <salam@lpthe.jussieu.fr>
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| 42 | //
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| 43 | // * added radius and seed threshold information in the plugin
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| 44 | // description
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| 45 | //
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| 46 | // 2009-01-06 Gregory Soyez <soyez@fastjet.fr>
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| 47 | //
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| 48 | // * Encapsulated the CMS code into a plugin for FastJet
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| 49 | // * inserted the deltaPhi and deltaR2 codes from
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| 50 | // DataFormats/Math/interface/deltaPhi.h (rev 1.1)
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| 51 | // DataFormats/Math/interface/deltaR.h (rev 1.2)
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| 52 | // * Adapted the code to use PseusoJet rather than 'InputItem'
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| 53 | // and 'InputCollection'
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| 54 | // * use the FastJet clustering history structures instead of
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| 55 | // the ProtoJet one used by CMS.
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| 56 |
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| 57 |
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| 58 | // fastjet stuff
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| 59 | #include "fastjet/ClusterSequence.hh"
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| 60 | #include "fastjet/CMSIterativeConePlugin.hh"
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| 61 |
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| 62 | // other stuff
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| 63 | #include <vector>
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| 64 | #include <list>
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| 65 | #include <sstream>
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| 66 | #include "SortByEt.h"
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| 67 |
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| 68 | FASTJET_BEGIN_NAMESPACE // defined in fastjet/internal/base.hh
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| 69 |
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| 70 | using namespace std;
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| 71 | using namespace cms;
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| 72 |
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| 73 | //------------------------------------------------------
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| 74 | // some tools
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| 75 | //------------------------------------------------------
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| 76 | template <class T>
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| 77 | T deltaPhi (T phi1, T phi2) {
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| 78 | T result = phi1 - phi2;
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| 79 | while (result > M_PI) result -= 2*M_PI;
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| 80 | while (result <= -M_PI) result += 2*M_PI;
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| 81 | return result;
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| 82 | }
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| 83 |
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| 84 | template <class T>
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| 85 | T deltaR2 (T eta1, T phi1, T eta2, T phi2) {
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| 86 | T deta = eta1 - eta2;
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| 87 | T dphi = deltaPhi (phi1, phi2);
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| 88 | return deta*deta + dphi*dphi;
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| 89 | }
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| 90 |
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| 91 | //------------------------------------------------------
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| 92 | bool CMSIterativeConePlugin::_first_time = true;
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| 93 |
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| 94 | string CMSIterativeConePlugin::description () const {
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| 95 | ostringstream desc;
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| 96 | desc << "CMSIterativeCone plugin with R = " << theConeRadius << " and seed threshold = " << theSeedThreshold;
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| 97 | return desc.str();
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| 98 | }
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| 99 |
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| 100 | void CMSIterativeConePlugin::run_clustering(ClusterSequence & clust_seq) const {
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| 101 | // print a banner if we run this for the first time
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| 102 | _print_banner(clust_seq.fastjet_banner_stream());
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| 103 |
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| 104 | //make a list of input objects ordered by ET
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| 105 | //cout << "copying the list of particles" << endl;
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| 106 | list<PseudoJet> input;
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| 107 | for (unsigned int i=0 ; i<clust_seq.jets().size() ; i++) {
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| 108 | input.push_back(clust_seq.jets()[i]);
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| 109 | }
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| 110 | NumericSafeGreaterByEt<PseudoJet> compCandidate;
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| 111 | //cout << "sorting" << endl;
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| 112 | input.sort(compCandidate);
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| 113 |
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| 114 | //find jets
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| 115 | //cout << "launching the main loop" << endl;
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| 116 | while( !input.empty() && (input.front().Et() > theSeedThreshold )) {
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| 117 | //cone centre
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| 118 | double eta0=input.front().eta();
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| 119 | double phi0=input.front().phi();
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| 120 | //protojet properties
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| 121 | double eta=0;
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| 122 | double phi=0;
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| 123 | double et=0;
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| 124 | //list of towers in cone
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| 125 | list< list<PseudoJet>::iterator> cone;
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| 126 | for(int iteration=0;iteration<100;iteration++){
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| 127 | //cout << "iterating" << endl;
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| 128 | cone.clear();
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| 129 | eta=0;
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| 130 | phi=0;
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| 131 | et=0;
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| 132 | for(list<PseudoJet>::iterator inp=input.begin();
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| 133 | inp!=input.end();inp++){
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| 134 | const PseudoJet tower = *inp;
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| 135 | if( deltaR2(eta0,phi0,tower.eta(),tower.phi()) <
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| 136 | theConeRadius*theConeRadius) {
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| 137 | double tower_et = tower.Et();
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| 138 | cone.push_back(inp);
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| 139 | eta+= tower_et*tower.eta();
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| 140 | double dphi=tower.phi()-phi0;
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| 141 | if(dphi>M_PI) dphi-=2*M_PI;
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| 142 | else if(dphi<=-M_PI) dphi+=2*M_PI;
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| 143 | phi+=tower_et*dphi;
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| 144 | et +=tower_et;
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| 145 | }
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| 146 | }
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| 147 | eta=eta/et;
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| 148 | phi=phi0+phi/et;
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| 149 | if(phi>M_PI)phi-=2*M_PI;
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| 150 | else if(phi<=-M_PI)phi+=2*M_PI;
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| 151 |
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| 152 | if(fabs(eta-eta0)<.001 && fabs(phi-phi0)<.001) break;//stable cone found
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| 153 | eta0=eta;
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| 154 | phi0=phi;
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| 155 | }
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| 156 |
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| 157 | //cout << "make the jet final" << endl;
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| 158 |
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| 159 | //make a final jet and remove the jet constituents from the input list
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| 160 | // InputCollection jetConstituents;
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| 161 | // list< list<InputItem>::iterator>::const_iterator inp;
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| 162 | // for(inp=cone.begin();inp!=cone.end();inp++) {
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| 163 | // jetConstituents.push_back(**inp);
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| 164 | // input.erase(*inp);
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| 165 | // }
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| 166 | // fOutput->push_back (ProtoJet (jetConstituents));
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| 167 | //
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| 168 | // IMPORTANT NOTE:
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| 169 | // while the stability of the stable cone is tested using the Et
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| 170 | // scheme recombination, the final jet uses E-scheme
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| 171 | // recombination.
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| 172 | //
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| 173 | // The technique used here is the same as what we already used for
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| 174 | // SISCone except that we act on the 'cone' list.
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| 175 | // We successively merge the particles that make up the cone jet
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| 176 | // until we have all particles in it. We start off with the zeroth
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| 177 | // particle.
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| 178 | list< list<PseudoJet>::iterator>::const_iterator inp;
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| 179 | inp = cone.begin();
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| 180 | int jet_k = (*inp)->cluster_hist_index();
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| 181 | // gps tmp
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| 182 | //float px=(*inp)->px(), py=(*inp)->py(), pz=(*inp)->pz(), E = (*inp)->E();
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| 183 |
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| 184 | // remove the particle from the list and jump to the next one
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| 185 | input.erase(*inp);
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| 186 | inp++;
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| 187 |
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| 188 | // now loop over the remaining particles
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| 189 | while (inp != cone.end()){
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| 190 | // take the last result of the merge
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| 191 | int jet_i = jet_k;
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| 192 | // and the next element of the jet
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| 193 | int jet_j = (*inp)->cluster_hist_index();
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| 194 | // and merge them (with a fake dij)
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| 195 | double dij = 0.0;
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| 196 |
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| 197 | // create the new jet by hand so that we can adjust its user index
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| 198 | // Note again the use of the E-scheme recombination here!
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| 199 | PseudoJet newjet = clust_seq.jets()[jet_i] + clust_seq.jets()[jet_j];
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| 200 |
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| 201 | // gps tmp to try out floating issues
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| 202 | //px+=(*inp)->px(), py+=(*inp)->py(), pz+=(*inp)->pz(), E += (*inp)->E();
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| 203 | //PseudoJet newjet(px,py,pz,E);
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| 204 |
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| 205 | clust_seq.plugin_record_ij_recombination(jet_i, jet_j, dij, newjet, jet_k);
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| 206 |
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| 207 | // remove the particle from the list and jump to the next one
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| 208 | input.erase(*inp);
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| 209 | inp++;
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| 210 | }
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| 211 |
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| 212 | // we have merged all the jet's particles into a single object, so now
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| 213 | // "declare" it to be a beam (inclusive) jet.
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| 214 | // [NB: put a sensible looking d_iB just to be nice...]
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| 215 | double d_iB = clust_seq.jets()[jet_k].perp2();
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| 216 | clust_seq.plugin_record_iB_recombination(jet_k, d_iB);
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| 217 |
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| 218 |
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| 219 | } //loop over seeds ended
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| 220 |
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| 221 | }
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| 222 |
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| 223 | // print a banner for reference to the 3rd-party code
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| 224 | void CMSIterativeConePlugin::_print_banner(ostream *ostr) const{
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| 225 | if (! _first_time) return;
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| 226 | _first_time=false;
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| 227 |
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| 228 | // make sure the user has not set the banner stream to NULL
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| 229 | if (!ostr) return;
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| 230 |
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| 231 | (*ostr) << "#-------------------------------------------------------------------------" << endl;
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| 232 | (*ostr) << "# You are running the CMS Iterative Cone plugin for FastJet " << endl;
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| 233 | (*ostr) << "# Original code by the CMS collaboration adapted by the FastJet authors " << endl;
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| 234 | (*ostr) << "# If you use this plugin, please cite " << endl;
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| 235 | (*ostr) << "# G. L. Bayatian et al. [CMS Collaboration], " << endl;
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| 236 | (*ostr) << "# CMS physics: Technical design report. " << endl;
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| 237 | (*ostr) << "# in addition to the usual FastJet reference. " << endl;
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| 238 | (*ostr) << "#-------------------------------------------------------------------------" << endl;
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| 239 |
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| 240 | // make sure we really have the output done.
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| 241 | ostr->flush();
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| 242 | }
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| 243 |
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| 244 | FASTJET_END_NAMESPACE // defined in fastjet/internal/base.hh
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