source: HiSusy/trunk/Delphes/Delphes-3.0.9/external/fastjet/plugins/NestedDefs/NestedDefsPlugin.cc @ 5

Last change on this file since 5 was 5, checked in by zerwas, 11 years ago

update to Delphes-3.0.9

File size: 5.0 KB
Line 
1//STARTHEADER
2// $Id: NestedDefsPlugin.cc 859 2012-11-28 01:49:23Z pavel $
3//
4// Copyright (c) 2007-2011, Matteo Cacciari, Gavin P. Salam and Gregory Soyez
5//
6//----------------------------------------------------------------------
7// This file is part of FastJet.
8//
9//  FastJet is free software; you can redistribute it and/or modify
10//  it under the terms of the GNU General Public License as published by
11//  the Free Software Foundation; either version 2 of the License, or
12//  (at your option) any later version.
13//
14//  The algorithms that underlie FastJet have required considerable
15//  development and are described in hep-ph/0512210. If you use
16//  FastJet as part of work towards a scientific publication, please
17//  include a citation to the FastJet paper.
18//
19//  FastJet is distributed in the hope that it will be useful,
20//  but WITHOUT ANY WARRANTY; without even the implied warranty of
21//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
22//  GNU General Public License for more details.
23//
24//  You should have received a copy of the GNU General Public License
25//  along with FastJet. If not, see <http://www.gnu.org/licenses/>.
26//----------------------------------------------------------------------
27//ENDHEADER
28
29// TODO
30// ? Maybe one could provide additional recomb. dists as an "extra".;
31
32// fastjet stuff
33#include "fastjet/ClusterSequence.hh"
34#include "fastjet/NestedDefsPlugin.hh"
35
36// other stuff
37#include <vector>
38#include <sstream>
39
40FASTJET_BEGIN_NAMESPACE      // defined in fastjet/internal/base.hh
41
42using namespace std;
43
44string NestedDefsPlugin::description () const {
45  ostringstream desc;
46 
47  desc << "NestedDefs: successive application of " ;
48  unsigned int i=1;
49  for (list<JetDefinition>::const_iterator it=_defs.begin();it!=_defs.end();it++){
50    desc << "Definition " << i++ << " [" << it->description() << "] - ";
51  }
52
53  return desc.str();
54}
55
56void NestedDefsPlugin::run_clustering(ClusterSequence & clust_seq) const {
57  vector<PseudoJet> momenta;
58
59  // build the initial list of particles
60  momenta = clust_seq.jets();
61  unsigned int step_n = momenta.size();
62
63  // initialise the conversion table, which works as follows
64  // conversion_table[step_cs_jet_index] = main_cs_jet_index
65  vector<unsigned int> conversion_table(2*step_n);
66  vector<unsigned int> new_conversion_table;
67  for (unsigned int i=0;i<step_n;i++)
68    conversion_table[i]=i;
69
70  // Now the steps go as follows:
71  // for each definition in the list,
72  //  - do the clustering,
73  //  - copy the history into the main one
74  //  - update the list of momenta and the index conversion table
75  list<JetDefinition>::const_iterator def_iterator = _defs.begin();
76  unsigned int def_index=0;
77  bool last_def=false;
78
79  while (def_iterator!=_defs.end()){
80    last_def = (def_index == (_defs.size()-1));
81
82    // do the clustering
83    ClusterSequence step_cs(momenta, *def_iterator);
84
85    // clear the momenta as we shall fill them again
86    momenta.clear();
87    new_conversion_table.clear();
88
89    // retrieve the history
90    const vector<ClusterSequence::history_element> & step_history = step_cs.history();
91
92    // copy the history
93    // note that we skip the initial steps which are just the
94    // declaration of the particles.
95    vector<ClusterSequence::history_element>::const_iterator
96      hist_iterator = step_history.begin();
97
98    for (unsigned int i=step_n;i!=0;i--)
99      hist_iterator++;
100
101    while (hist_iterator != step_history.end()){
102      // check if it is a recombination with the beam or a simple recombination
103      if (hist_iterator->parent2 == ClusterSequence::BeamJet){
104        // save this jet for future clustering
105        // unless we've reached the last def in which case, record the clustering
106        unsigned int step_jet_index = step_cs.history()[hist_iterator->parent1].jetp_index;
107        if (last_def){
108          clust_seq.plugin_record_iB_recombination(conversion_table[step_jet_index], 
109                                                   hist_iterator->dij);
110        } else {
111          momenta.push_back(step_cs.jets()[step_jet_index]);
112          new_conversion_table.push_back(conversion_table[step_jet_index]);
113        }
114      } else {
115        // record combination
116        // note that we set the recombination distance to 0 except for the last alg
117        unsigned int step_jet1_index = step_cs.history()[hist_iterator->parent1].jetp_index;
118        unsigned int step_jet2_index = step_cs.history()[hist_iterator->parent2].jetp_index;
119        PseudoJet newjet = step_cs.jets()[hist_iterator->jetp_index];
120        int jet_k;
121        clust_seq.plugin_record_ij_recombination(conversion_table[step_jet1_index], 
122                                                 conversion_table[step_jet2_index],
123                                                 last_def ? hist_iterator->dij : 0.0,
124                                                 newjet, jet_k);
125
126        // save info in the conversion table for tracking purposes
127        conversion_table[hist_iterator->jetp_index]=jet_k;
128      }
129
130      // go to the next history element
131      hist_iterator++;
132    }
133
134    // finalise this step:
135    //  - update nr of particles
136    //  - update conversion table
137    step_n = momenta.size();
138    for (unsigned int i=0;i<step_n;i++)
139      conversion_table[i] = new_conversion_table[i];
140
141    // go to the next alg
142    def_index++;
143    def_iterator++;
144  }
145
146}
147
148FASTJET_END_NAMESPACE      // defined in fastjet/internal/base.hh
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