1 | //STARTHEADER |
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2 | // $Id: ClusterSequence_N2.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 | |
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30 | // The plain N^2 part of the ClusterSequence class -- separated out |
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31 | // from the rest of the class implementation so as to speed up |
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32 | // compilation of this particular part while it is under test. |
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33 | |
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34 | #include "fastjet/internal/ClusterSequence_N2.icc" |
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35 | |
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36 | #include<iostream> |
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37 | |
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38 | FASTJET_BEGIN_NAMESPACE // defined in fastjet/internal/base.hh |
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39 | |
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40 | |
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41 | using namespace std; |
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42 | |
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43 | |
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44 | //************************************************************************* |
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45 | // |
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46 | // THINGS FOR E+E- |
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47 | // |
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48 | //************************************************************************* |
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49 | |
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50 | |
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51 | //---------------------------------------------------------------------- |
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52 | template<> inline void ClusterSequence::_bj_set_jetinfo( |
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53 | EEBriefJet * const jetA, const int _jets_index) const { |
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54 | |
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55 | double E = _jets[_jets_index].E(); |
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56 | double scale = E*E; // the default energy scale for the kt alg |
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57 | double p = jet_def().extra_param(); // in case we're ee_genkt |
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58 | switch (_jet_algorithm) { |
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59 | case ee_kt_algorithm: |
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60 | assert(_Rparam > 2.0); // force this to be true! [not best place, but works] |
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61 | // recall that _invR2 is artificially set to 1 for this alg |
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62 | // so that we automatically have dij = scale * 2(1-cos theta_ij) |
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63 | // Normally, _Rparam should be automatically set to 4 from JetDefinition |
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64 | break; |
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65 | case ee_genkt_algorithm: |
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66 | if (p <= 0 && scale < 1e-300) scale = 1e-300; // same dodgy safety as genkt |
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67 | scale = pow(scale,p); |
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68 | break; |
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69 | default: |
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70 | throw Error("Unrecognised jet algorithm"); |
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71 | } |
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72 | jetA->kt2 = scale; // "kt2" might one day be renamed as "scale" or some such |
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73 | |
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74 | double norm = _jets[_jets_index].modp2(); |
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75 | if (norm > 0) { |
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76 | norm = 1.0/sqrt(norm); |
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77 | jetA->nx = norm * _jets[_jets_index].px(); |
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78 | jetA->ny = norm * _jets[_jets_index].py(); |
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79 | jetA->nz = norm * _jets[_jets_index].pz(); |
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80 | } else { |
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81 | jetA->nx = 0.0; |
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82 | jetA->ny = 0.0; |
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83 | jetA->nz = 1.0; |
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84 | } |
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85 | jetA->_jets_index = _jets_index; |
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86 | // initialise NN info as well |
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87 | jetA->NN_dist = _R2; |
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88 | jetA->NN = NULL; |
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89 | } |
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90 | |
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91 | //---------------------------------------------------------------------- |
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92 | // returns the angular distance between the two jets |
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93 | template<> double ClusterSequence::_bj_dist( |
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94 | const EEBriefJet * const jeta, |
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95 | const EEBriefJet * const jetb) const { |
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96 | double dist = 1.0 |
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97 | - jeta->nx*jetb->nx |
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98 | - jeta->ny*jetb->ny |
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99 | - jeta->nz*jetb->nz; |
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100 | dist *= 2; // distance is _2_*min(Ei^2,Ej^2)*(1-cos theta) |
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101 | return dist; |
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102 | } |
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103 | |
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104 | |
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105 | |
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106 | // get explicit copies of the two N2 cluster cases we need |
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107 | // plain BriefJet |
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108 | void ClusterSequence::_simple_N2_cluster_BriefJet() { |
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109 | _simple_N2_cluster<BriefJet>(); |
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110 | } |
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111 | |
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112 | |
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113 | // e+e- BriefJet |
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114 | void ClusterSequence::_simple_N2_cluster_EEBriefJet() { |
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115 | _simple_N2_cluster<EEBriefJet>(); |
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116 | } |
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117 | |
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118 | // //---------------------------------------------------------------------- |
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119 | // /// Force instantiation of desired versions of _simple_N2_cluster |
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120 | // /// |
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121 | // /// This is not very elegant... |
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122 | // void ClusterSequence::_dummy_N2_cluster_instantiation() { |
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123 | // _simple_N2_cluster<BriefJet>(); |
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124 | // _simple_N2_cluster<EEBriefJet>(); |
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125 | // } |
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126 | |
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127 | FASTJET_END_NAMESPACE |
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128 | |
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