FastJet  3.3.0
ClusterSequencePassiveArea.cc
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30 
31 #include "fastjet/ClusterSequencePassiveArea.hh"
32 #include "fastjet/ClusterSequenceVoronoiArea.hh"
33 
34 FASTJET_BEGIN_NAMESPACE // defined in fastjet/internal/base.hh
35 
36 
37 using namespace std;
38 
39 //----------------------------------------------------------------------
40 /// global routine for initialising and running a passive area that is
41 /// correct in general, but that chooses an optimal approach for
42 /// various special cases.
43 void ClusterSequencePassiveArea::_initialise_and_run_PA (
44  const JetDefinition & jet_def_in,
45  const GhostedAreaSpec & area_spec,
46  const bool & writeout_combinations) {
47 
48  if (jet_def_in.jet_algorithm() == kt_algorithm) {
49  // first run the passive area
50  ClusterSequenceVoronoiArea csva(_jets,jet_def_in,VoronoiAreaSpec(1.0));
51  // now set up and transfer relevant information
52  // first the clustering sequence
53  transfer_from_sequence(csva);
54  // then the areas
55  _resize_and_zero_AA();
56  for (unsigned i = 0; i < _history.size(); i++) {
57  int ijetp = _history[i].jetp_index;
58  if (ijetp != Invalid) {
59  _average_area[i] = csva.area(_jets[ijetp]);
60  _average_area_4vector[i] = csva.area_4vector(_jets[ijetp]);
61  }
62  }
63 
64  } else if (jet_def_in.jet_algorithm() == cambridge_algorithm) {
65  // run a variant of the cambridge algorithm that has been hacked
66  // to deal with passive areas
67  JetDefinition tmp_jet_def = jet_def_in;
68  tmp_jet_def.set_jet_finder(cambridge_for_passive_algorithm);
69  tmp_jet_def.set_extra_param(sqrt(area_spec.mean_ghost_kt()));
70  _initialise_and_run_AA(tmp_jet_def, area_spec, writeout_combinations);
71  _jet_def = jet_def_in;
72 
73  } else if (jet_def_in.jet_algorithm() == antikt_algorithm) {
74  // for the antikt algorithm, passive and active are identical
75  _initialise_and_run_AA(jet_def_in, area_spec, writeout_combinations);
76 
77  } else if (jet_def_in.jet_algorithm() == plugin_algorithm &&
78  jet_def_in.plugin()->supports_ghosted_passive_areas()) {
79  // for some plugin algorithms, one can "prime" the algorithm with information
80  // about the ghost scale, and then an "AA" run will actually give a passive
81  // area
82  double ghost_sep_scale_store = jet_def_in.plugin()->ghost_separation_scale();
83  jet_def_in.plugin()->set_ghost_separation_scale(sqrt(area_spec.mean_ghost_kt()));
84  _initialise_and_run_AA(jet_def_in, area_spec, writeout_combinations);
85 
86  // restore the original ghost_sep_scale
87  jet_def_in.plugin()->set_ghost_separation_scale(ghost_sep_scale_store);
88 
89  } else {
90  // for a generic algorithm, just run the 1GhostPassiveArea
91  _initialise_and_run_1GPA(jet_def_in, area_spec, writeout_combinations);
92  }
93 }
94 
95 //----------------------------------------------------------------------
96 // dispatch to most relevant empty area calculation...
97 double ClusterSequencePassiveArea::empty_area (const Selector & selector) const {
98  if (jet_def().jet_algorithm() == kt_algorithm) {
99  // run the naive algorithm
100  return ClusterSequenceAreaBase::empty_area(selector);
101  } else {
102  return ClusterSequence1GhostPassiveArea::empty_area(selector);
103  }
104 }
105 
106 
107 FASTJET_END_NAMESPACE // defined in fastjet/internal/base.hh
108 
the longitudinally invariant kt algorithm
any plugin algorithm supplied by the user
Class that encodes information about cuts and other selection criteria that can be applied to PseudoJ...
Definition: Selector.hh:149
like the k_t but with distance measures dij = min(1/kti^2,1/ktj^2) Delta R_{ij}^2 / R^2 diB = 1/kti^2...
the longitudinally invariant variant of the cambridge algorithm (aka Aachen algoithm).