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ClusterSequencePassiveArea.cc
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2 // $Id: ClusterSequencePassiveArea.cc 2687 2011-11-14 11:17:51Z soyez $
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28 
29 #include "fastjet/ClusterSequencePassiveArea.hh"
30 #include "fastjet/ClusterSequenceVoronoiArea.hh"
31 
32 FASTJET_BEGIN_NAMESPACE // defined in fastjet/internal/base.hh
33 
34 
35 using namespace std;
36 
37 //----------------------------------------------------------------------
38 /// global routine for initialising and running a passive area that is
39 /// correct in general, but that chooses an optimal approach for
40 /// various special cases.
41 void ClusterSequencePassiveArea::_initialise_and_run_PA (
42  const JetDefinition & jet_def_in,
43  const GhostedAreaSpec & area_spec,
44  const bool & writeout_combinations) {
45 
46  if (jet_def_in.jet_algorithm() == kt_algorithm) {
47  // first run the passive area
48  ClusterSequenceVoronoiArea csva(_jets,jet_def_in,VoronoiAreaSpec(1.0));
49  // now set up and transfer relevant information
50  // first the clustering sequence
51  transfer_from_sequence(csva);
52  // then the areas
53  _resize_and_zero_AA();
54  for (unsigned i = 0; i < _history.size(); i++) {
55  int ijetp = _history[i].jetp_index;
56  if (ijetp != Invalid) {
57  _average_area[i] = csva.area(_jets[ijetp]);
58  _average_area_4vector[i] = csva.area_4vector(_jets[ijetp]);
59  }
60  }
61 
62  } else if (jet_def_in.jet_algorithm() == cambridge_algorithm) {
63  // run a variant of the cambridge algorithm that has been hacked
64  // to deal with passive areas
65  JetDefinition tmp_jet_def = jet_def_in;
66  tmp_jet_def.set_jet_finder(cambridge_for_passive_algorithm);
67  tmp_jet_def.set_extra_param(sqrt(area_spec.mean_ghost_kt()));
68  _initialise_and_run_AA(tmp_jet_def, area_spec, writeout_combinations);
69  _jet_def = jet_def_in;
70 
71  } else if (jet_def_in.jet_algorithm() == antikt_algorithm) {
72  // for the antikt algorithm, passive and active are identical
73  _initialise_and_run_AA(jet_def_in, area_spec, writeout_combinations);
74 
75  } else if (jet_def_in.jet_algorithm() == plugin_algorithm &&
76  jet_def_in.plugin()->supports_ghosted_passive_areas()) {
77  // for some plugin algorithms, one can "prime" the algorithm with information
78  // about the ghost scale, and then an "AA" run will actually give a passive
79  // area
80  double ghost_sep_scale_store = jet_def_in.plugin()->ghost_separation_scale();
81  jet_def_in.plugin()->set_ghost_separation_scale(sqrt(area_spec.mean_ghost_kt()));
82  _initialise_and_run_AA(jet_def_in, area_spec, writeout_combinations);
83 
84  // restore the original ghost_sep_scale
85  jet_def_in.plugin()->set_ghost_separation_scale(ghost_sep_scale_store);
86 
87  } else {
88  // for a generic algorithm, just run the 1GhostPassiveArea
89  _initialise_and_run_1GPA(jet_def_in, area_spec, writeout_combinations);
90  }
91 }
92 
93 //----------------------------------------------------------------------
94 // dispatch to most relevant empty area calculation...
95 double ClusterSequencePassiveArea::empty_area (const Selector & selector) const {
96  if (jet_def().jet_algorithm() == kt_algorithm) {
97  // run the naive algorithm
98  return ClusterSequenceAreaBase::empty_area(selector);
99  } else {
100  return ClusterSequence1GhostPassiveArea::empty_area(selector);
101  }
102 }
103 
104 
105 FASTJET_END_NAMESPACE // defined in fastjet/internal/base.hh
106