FastJet 3.0.2
ATLASConePlugin.cc
00001 //STARTHEADER
00002 // $Id: ATLASConePlugin.cc 2777 2011-11-25 15:01:56Z soyez $
00003 //
00004 // Copyright (c) 2007-2011, Matteo Cacciari, Gavin P. Salam and Gregory Soyez
00005 //
00006 //----------------------------------------------------------------------
00007 // This file is part of FastJet.
00008 //
00009 //  FastJet is free software; you can redistribute it and/or modify
00010 //  it under the terms of the GNU General Public License as published by
00011 //  the Free Software Foundation; either version 2 of the License, or
00012 //  (at your option) any later version.
00013 //
00014 //  The algorithms that underlie FastJet have required considerable
00015 //  development and are described in hep-ph/0512210. If you use
00016 //  FastJet as part of work towards a scientific publication, please
00017 //  include a citation to the FastJet paper.
00018 //
00019 //  FastJet is distributed in the hope that it will be useful,
00020 //  but WITHOUT ANY WARRANTY; without even the implied warranty of
00021 //  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00022 //  GNU General Public License for more details.
00023 //
00024 //  You should have received a copy of the GNU General Public License
00025 //  along with FastJet. If not, see <http://www.gnu.org/licenses/>.
00026 //----------------------------------------------------------------------
00027 //ENDHEADER
00028 
00029 // fastjet stuff
00030 #include "fastjet/ClusterSequence.hh"
00031 #include "fastjet/ATLASConePlugin.hh"
00032 
00033 // SpartyJet stuff
00034 #include "CommonUtils.hh"
00035 #include "JetConeFinderTool.hh"
00036 #include "JetSplitMergeTool.hh"
00037 
00038 // other stuff
00039 #include <vector>
00040 #include <sstream>
00041 
00042 FASTJET_BEGIN_NAMESPACE      // defined in fastjet/internal/base.hh
00043 
00044 using namespace std;
00045 
00046 bool ATLASConePlugin::_first_time = true;
00047 
00048 string ATLASConePlugin::description () const {
00049   ostringstream desc;
00050   desc << "ATLASCone plugin with R = "<< _radius 
00051        << ", seed threshold = " << _seedPt
00052        << ", overlap threshold f = " << _f;
00053   return desc.str();
00054 }
00055 
00056 void ATLASConePlugin::run_clustering(ClusterSequence & clust_seq) const {
00057   // print a banner if we run this for the first time
00058   _print_banner(clust_seq.fastjet_banner_stream());
00059 
00060 
00061   // transfer the list of PseudoJet into a atlas::Jet::jet_list_t
00062   //  jet_list_t is a vector<Jet*>
00063   // We set the index of the 4-vect to trace the constituents at the end
00064   //------------------------------------------------------------------
00065   // cout << "ATLASConePlugin: transferring vectors from ClusterSequence" << endl;
00066   atlas::JetConeFinderTool::jetcollection_t jets_ptr;
00067   vector<atlas::Jet*> particles_ptr;
00068 
00069   for (unsigned int i=0 ; i<clust_seq.jets().size() ; i++) {
00070     const PseudoJet & mom = clust_seq.jets()[i];
00071     
00072     // first create the particle
00073     atlas::Jet *particle = new atlas::Jet(mom.px(), mom.py(), mom.pz(), mom.E(), i);
00074     particles_ptr.push_back(particle);
00075 
00076     // then add it to the list of particles we'll use for the clustering
00077     atlas::Jet *jet = new atlas::Jet;
00078     jet->set_index(particle->index());
00079     jet->addConstituent(particle);
00080 
00081     // and finally add that one to the list of jets
00082     jets_ptr.push_back(jet);
00083   }
00084   // cout << "ATLASCone: " << jets_ptr.size() << " particles to cluster" << endl;
00085 
00086   // search the stable cones
00087   //------------------------------------------------------------------
00088   // cout << "ATLASConePlugin: searching for stable cones" << endl;
00089   atlas::JetConeFinderTool stable_cone_finder;
00090 
00091   // set the parameters
00092   stable_cone_finder.m_coneR  = _radius;
00093   stable_cone_finder.m_seedPt = _seedPt;
00094 
00095   // really do the search.
00096   // Note that the list of protocones is returned 
00097   // through the argument
00098   stable_cone_finder.execute(jets_ptr);
00099   // cout << "ATLASCone: " << jets_ptr.size() << " stable cones found" << endl;
00100 
00101   // perform the split-merge
00102   //------------------------------------------------------------------
00103   // cout << "ATLASConePlugin: running the split-merge" << endl;
00104   atlas::JetSplitMergeTool split_merge;
00105   
00106   // set the parameters
00107   split_merge.m_f = _f;
00108 
00109   // do the work
00110   // again, the list of jets is returned through the argument
00111   split_merge.execute(&jets_ptr);
00112   // cout << "ATLASCone: " << jets_ptr.size() << " jets after split--merge" << endl;
00113 
00114   // build the FastJet jets (a la SISConePlugin)
00115   //------------------------------------------------------------------
00116   // cout << "ATLASConePlugin: backporting jets to the ClusterSequence" << endl;
00117   for (atlas::Jet::jet_list_t::iterator jet_it = jets_ptr.begin() ;
00118          jet_it != jets_ptr.end(); jet_it++){
00119     // iterate over the constituents, starting from the first one
00120     // that we just take as a reference
00121     atlas::Jet::constit_vect_t::iterator constit_it = (*jet_it)->firstConstituent();
00122     // cout << " atlas: jet has " << (*jet_it)->getConstituentNum() << " constituents" << endl;
00123     int jet_k = (*constit_it)->index();
00124     constit_it++;
00125     
00126     // loop over the remaining particles
00127     while (constit_it != (*jet_it)->lastConstituent()){
00128       // take the last result of the merge
00129       int jet_i = jet_k;
00130       // and the next element of the jet
00131       int jet_j = (*constit_it)->index();
00132       // and merge them (with a fake dij)
00133       double dij = 0.0;
00134 
00135       // create the new jet by hand so that we can adjust its user index
00136       // Note again the use of the E-scheme recombination here!
00137       PseudoJet newjet = clust_seq.jets()[jet_i] + clust_seq.jets()[jet_j];
00138       clust_seq.plugin_record_ij_recombination(jet_i, jet_j, dij, newjet, jet_k);
00139 
00140       // jump to the next constituent
00141       constit_it++;
00142     }
00143 
00144     // we have merged all the jet's particles into a single object, so now
00145     // "declare" it to be a beam (inclusive) jet.
00146     // [NB: put a sensible looking d_iB just to be nice...]
00147     double d_iB = clust_seq.jets()[jet_k].perp2();
00148     clust_seq.plugin_record_iB_recombination(jet_k, d_iB);
00149   }
00150     
00151   // cout << "ATLASConePlugin: Bye" << endl;
00152   clear_list(particles_ptr);
00153   clear_list(jets_ptr);
00154 }
00155 
00156 // print a banner for reference to the 3rd-party code
00157 void ATLASConePlugin::_print_banner(ostream *ostr) const{
00158   if (! _first_time) return;
00159   _first_time=false;
00160 
00161   // make sure the user has not set the banner stream to NULL
00162   if (!ostr) return;  
00163 
00164   (*ostr) << "#-------------------------------------------------------------------------" << endl;
00165   (*ostr) << "# You are running the ATLAS Cone plugin for FastJet                       " << endl;
00166   (*ostr) << "# Original code from SpartyJet; interface by the FastJet authors          " << endl;
00167   (*ostr) << "# If you use this plugin, please cite                                     " << endl;
00168   (*ostr) << "#   P.A. Delsart, K. Geerlings, J. Huston, B. Martin and C. Vermilion,    " << endl;
00169   (*ostr) << "#   SpartyJet, http://projects.hepforge.org/spartyjet                     " << endl;
00170   (*ostr) << "# in addition to the usual FastJet reference.                             " << endl;
00171   (*ostr) << "#-------------------------------------------------------------------------" << endl;
00172 
00173   // make sure we really have the output done.
00174   ostr->flush();
00175 }
00176 
00177 
00178 FASTJET_END_NAMESPACE      // defined in fastjet/internal/base.hh
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