1 | //STARTHEADER |
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2 | // $Id: ClusterSequenceActiveAreaExplicitGhosts.cc 859 2012-11-28 01:49:23Z pavel $ |
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3 | // |
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4 | // Copyright (c) 2005-2011, Matteo Cacciari, Gavin P. Salam and Gregory Soyez |
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5 | // |
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6 | //---------------------------------------------------------------------- |
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7 | // This file is part of FastJet. |
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8 | // |
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9 | // FastJet is free software; you can redistribute it and/or modify |
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10 | // it under the terms of the GNU General Public License as published by |
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11 | // the Free Software Foundation; either version 2 of the License, or |
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12 | // (at your option) any later version. |
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13 | // |
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14 | // The algorithms that underlie FastJet have required considerable |
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15 | // development and are described in hep-ph/0512210. If you use |
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16 | // FastJet as part of work towards a scientific publication, please |
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17 | // include a citation to the FastJet paper. |
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18 | // |
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19 | // FastJet is distributed in the hope that it will be useful, |
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20 | // but WITHOUT ANY WARRANTY; without even the implied warranty of |
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21 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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22 | // GNU General Public License for more details. |
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23 | // |
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24 | // You should have received a copy of the GNU General Public License |
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25 | // along with FastJet. If not, see <http://www.gnu.org/licenses/>. |
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26 | //---------------------------------------------------------------------- |
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27 | //ENDHEADER |
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28 | |
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29 | #include "fastjet/ClusterSequenceActiveAreaExplicitGhosts.hh" |
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30 | #include<limits> |
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31 | |
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32 | using namespace std; |
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33 | |
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34 | FASTJET_BEGIN_NAMESPACE // defined in fastjet/internal/base.hh |
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35 | |
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36 | // save some typing |
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37 | typedef ClusterSequenceActiveAreaExplicitGhosts ClustSeqActAreaEG; |
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38 | |
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39 | |
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40 | LimitedWarning ClustSeqActAreaEG::_warnings; |
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41 | |
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42 | //---------------------------------------------------------------------- |
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43 | /// |
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44 | void ClustSeqActAreaEG::_add_ghosts ( |
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45 | const GhostedAreaSpec & ghost_spec) { |
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46 | |
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47 | // add the ghosts to the jets |
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48 | ghost_spec.add_ghosts(_jets); |
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49 | |
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50 | // now add labelling... |
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51 | for (unsigned i = _initial_hard_n; i < _jets.size(); i++) { |
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52 | //_jets[i].set_user_index(1); |
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53 | _is_pure_ghost.push_back(true); |
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54 | } |
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55 | |
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56 | // and record some info from the ghost_spec |
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57 | _ghost_area = ghost_spec.actual_ghost_area(); |
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58 | _n_ghosts = ghost_spec.n_ghosts(); |
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59 | } |
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60 | |
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61 | |
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62 | //---------------------------------------------------------------------- |
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63 | // return the area of a jet |
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64 | double ClustSeqActAreaEG::area (const PseudoJet & jet) const { |
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65 | return _areas[jet.cluster_hist_index()]; |
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66 | } |
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67 | |
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68 | |
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69 | //---------------------------------------------------------------------- |
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70 | // return the total area |
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71 | double ClustSeqActAreaEG::total_area () const { |
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72 | return _n_ghosts * _ghost_area; |
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73 | } |
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74 | |
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75 | |
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76 | //---------------------------------------------------------------------- |
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77 | // return the extended area of a jet |
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78 | PseudoJet ClustSeqActAreaEG::area_4vector (const PseudoJet & jet) const { |
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79 | return _area_4vectors[jet.cluster_hist_index()]; |
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80 | } |
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81 | |
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82 | //---------------------------------------------------------------------- |
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83 | bool ClustSeqActAreaEG::is_pure_ghost(const PseudoJet & jet) const |
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84 | { |
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85 | return _is_pure_ghost[jet.cluster_hist_index()]; |
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86 | } |
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87 | |
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88 | //---------------------------------------------------------------------- |
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89 | bool ClustSeqActAreaEG::is_pure_ghost(int hist_ix) const |
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90 | { |
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91 | return hist_ix >= 0 ? _is_pure_ghost[hist_ix] : false; |
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92 | } |
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93 | |
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94 | //---------------------------------------------------------------------- |
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95 | double ClustSeqActAreaEG::empty_area(const Selector & selector) const { |
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96 | // make sure that the selector applies jet by jet |
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97 | if (! selector.applies_jet_by_jet()){ |
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98 | throw Error("ClusterSequenceActiveAreaExplicitGhosts: empty area can only be computed from selectors applying jet by jet"); |
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99 | } |
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100 | |
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101 | vector<PseudoJet> unclust = unclustered_particles(); |
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102 | double area_local = 0.0; |
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103 | for (unsigned iu = 0; iu < unclust.size(); iu++) { |
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104 | if (is_pure_ghost(unclust[iu]) && selector.pass(unclust[iu])) { |
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105 | area_local += _ghost_area; |
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106 | } |
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107 | } |
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108 | return area_local; |
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109 | } |
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110 | |
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111 | //====================================================================== |
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112 | // sort out the areas |
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113 | void ClustSeqActAreaEG::_post_process() { |
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114 | |
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115 | // first check for danger signals. |
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116 | // Establish largest ghost transverse momentum |
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117 | _max_ghost_perp2 = 0.0; |
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118 | for (int i = 0; i < _initial_n; i++) { |
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119 | if (_is_pure_ghost[i] && _jets[i].perp2() > _max_ghost_perp2) |
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120 | _max_ghost_perp2 = _jets[i].perp2(); |
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121 | } |
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122 | |
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123 | // now find out if any of the particles are close to danger |
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124 | double danger_ratio = numeric_limits<double>::epsilon(); |
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125 | danger_ratio = danger_ratio * danger_ratio; |
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126 | _has_dangerous_particles = false; |
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127 | for (int i = 0; i < _initial_n; i++) { |
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128 | if (!_is_pure_ghost[i] && |
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129 | danger_ratio * _jets[i].perp2() <= _max_ghost_perp2) { |
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130 | _has_dangerous_particles = true; |
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131 | break; |
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132 | } |
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133 | } |
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134 | |
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135 | if (_has_dangerous_particles) _warnings.warn("ClusterSequenceActiveAreaExplicitGhosts: \n ghosts not sufficiently soft wrt some of the input particles\n a common cause is (unphysical?) input particles with pt=0 but finite rapidity"); |
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136 | |
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137 | // sort out sizes |
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138 | _areas.resize(_history.size()); |
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139 | _area_4vectors.resize(_history.size()); |
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140 | _is_pure_ghost.resize(_history.size()); |
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141 | |
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142 | // copy(_jets.begin(), _jets.begin()+_initial_n, _area_4vectors.begin()); |
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143 | // for (int i = 0; i < _initial_n; i++) { |
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144 | // if (_is_pure_ghost[i]) { |
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145 | // _areas[i] = _ghost_area; |
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146 | // // normalise pt to be _ghost_area (NB we make use of fact that |
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147 | // // for initial particles, jet and clust_hist index are the same). |
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148 | // _area_4vectors[i] *= (_ghost_area/_jets[i].perp()); |
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149 | // } else { |
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150 | // _areas[i] = 0; |
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151 | // _area_4vectors[i].reset(0,0,0,0); |
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152 | // } |
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153 | // } |
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154 | |
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155 | // First set up areas for the initial particles (ghost=_ghost_area, |
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156 | // real particles = 0); recall that _initial_n here is the number of |
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157 | // particles including ghosts |
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158 | for (int i = 0; i < _initial_n; i++) { |
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159 | if (_is_pure_ghost[i]) { |
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160 | _areas[i] = _ghost_area; |
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161 | // normalise pt to be _ghost_area (NB we make use of fact that |
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162 | // for initial particles, jet and clust_hist index are the same). |
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163 | //_area_4vectors[i] = (_ghost_area/_jets[i].perp()) * _jets[i]; |
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164 | |
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165 | // NB: we use reset_momentum here, to ensure that the area 4 |
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166 | // vectors do not acquire any structure (the structure would not |
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167 | // be meaningful for an area, and it messes up the use count (-> |
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168 | // memory leaks if the user call delete_self_when_unused). |
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169 | _area_4vectors[i].reset_momentum(_jets[i]); |
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170 | _area_4vectors[i] *= (_ghost_area/_jets[i].perp()); |
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171 | } else { |
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172 | _areas[i] = 0; |
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173 | _area_4vectors[i] = PseudoJet(0.0,0.0,0.0,0.0); |
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174 | } |
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175 | } |
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176 | |
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177 | // next follow the branching through and set up the areas |
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178 | // and ghost-nature at each step of the clustering (rather than |
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179 | // each jet). |
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180 | for (unsigned i = _initial_n; i < _history.size(); i++) { |
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181 | if (_history[i].parent2 == BeamJet) { |
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182 | _is_pure_ghost[i] = _is_pure_ghost[_history[i].parent1]; |
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183 | _areas[i] = _areas[_history[i].parent1]; |
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184 | _area_4vectors[i] = _area_4vectors[_history[i].parent1]; |
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185 | } else { |
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186 | _is_pure_ghost[i] = _is_pure_ghost[_history[i].parent1] && |
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187 | _is_pure_ghost[_history[i].parent2] ; |
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188 | _areas[i] = _areas[_history[i].parent1] + |
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189 | _areas[_history[i].parent2] ; |
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190 | _jet_def.recombiner()->recombine(_area_4vectors[_history[i].parent1], |
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191 | _area_4vectors[_history[i].parent2], |
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192 | _area_4vectors[i]); |
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193 | // _area_4vectors[i] = _area_4vectors[_history[i].parent1] + |
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194 | // _area_4vectors[_history[i].parent2] ; |
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195 | } |
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196 | |
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197 | } |
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198 | |
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199 | } |
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200 | |
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201 | FASTJET_END_NAMESPACE |
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202 | |
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