1 | //FJSTARTHEADER
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2 | // $Id: Filter.cc 4442 2020-05-05 07:50:11Z soyez $
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3 | //
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4 | // Copyright (c) 2005-2020, 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. They are described in the original FastJet paper,
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16 | // hep-ph/0512210 and in the manual, arXiv:1111.6097. If you use
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17 | // FastJet as part of work towards a scientific publication, please
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18 | // quote the version you use and include a citation to the manual and
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19 | // optionally also to hep-ph/0512210.
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20 | //
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21 | // FastJet is distributed in the hope that it will be useful,
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22 | // but WITHOUT ANY WARRANTY; without even the implied warranty of
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23 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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24 | // GNU General Public License for more details.
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25 | //
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26 | // You should have received a copy of the GNU General Public License
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27 | // along with FastJet. If not, see <http://www.gnu.org/licenses/>.
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28 | //----------------------------------------------------------------------
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29 | //FJENDHEADER
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30 |
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31 | #include "fastjet/tools/Filter.hh"
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32 | #include "fastjet/tools/Recluster.hh"
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33 | #include "fastjet/tools/Subtractor.hh"
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34 | #include <fastjet/ClusterSequenceActiveAreaExplicitGhosts.hh>
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35 | #include <cassert>
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36 | #include <algorithm>
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37 | #include <sstream>
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38 | #include <typeinfo>
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39 |
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40 | using namespace std;
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41 |
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42 |
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43 | FASTJET_BEGIN_NAMESPACE // defined in fastjet/internal/base.hh
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44 |
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45 | //----------------------------------------------------------------------
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46 | // Filter class implementation
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47 | //----------------------------------------------------------------------
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48 |
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49 | // class description
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50 | string Filter::description() const {
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51 | if (!_initialised){
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52 | return "uninitialised Filter";
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53 | }
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54 |
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55 | ostringstream ostr;
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56 | ostr << "Filter with subjet_def = ";
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57 | if (_Rfiltfunc) {
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58 | ostr << "Cambridge/Aachen algorithm with dynamic Rfilt"
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59 | << " (recomb. scheme deduced from jet, or E-scheme if not unique)";
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60 | } else if (_Rfilt > 0) {
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61 | ostr << "Cambridge/Aachen algorithm with Rfilt = "
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62 | << _Rfilt
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63 | << " (recomb. scheme deduced from jet, or E-scheme if not unique)";
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64 | } else {
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65 | ostr << _subjet_def.description();
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66 | }
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67 | ostr<< ", selection " << _selector.description();
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68 | if (_subtractor) {
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69 | ostr << ", subtractor: " << _subtractor->description();
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70 | } else if (_rho != 0) {
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71 | ostr << ", subtracting with rho = " << _rho;
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72 | }
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73 | return ostr.str();
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74 | }
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75 |
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76 |
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77 | // core functions
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78 | //----------------------------------------------------------------------
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79 |
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80 | // return a vector of subjets, which are the ones that would be kept
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81 | // by the filtering
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82 | PseudoJet Filter::result(const PseudoJet &jet) const {
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83 | if (!_initialised){
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84 | //Q: do we throw or do we return an empty PJ?
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85 | throw Error("uninitialised Filter");
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86 | }
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87 |
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88 | // start by getting the list of subjets (including a list of sanity
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89 | // checks)
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90 | // NB: subjets is empty to begin with (see the comment for
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91 | // _set_filtered_elements_cafilt)
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92 | vector<PseudoJet> subjets;
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93 | //JetDefinition subjet_def;
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94 | bool ca_optimised = _set_filtered_elements(jet, subjets);
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95 |
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96 | // apply subtraction if needed:
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97 | if (_subtractor){
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98 | subjets = (*_subtractor)(subjets);
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99 | } else if (_rho!=0){
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100 | if (subjets.size()>0){
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101 | //const ClusterSequenceAreaBase *csab = subjets[0].validated_csab();
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102 | for (unsigned int i=0;i<subjets.size();i++){
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103 | //subjets[i]=csab->subtracted_jet(subjets[i], _rho);
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104 | subjets[i]=Subtractor(_rho)(subjets[i]);
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105 | }
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106 | }
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107 | }
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108 |
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109 | // now build the vector of kept and rejected subjets
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110 | vector<PseudoJet> kept, rejected;
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111 | // Note that in the following line we make a copy of the _selector
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112 | // to avoid issues with needing a mutable _selector
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113 | Selector selector_copy = _selector;
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114 | if (selector_copy.takes_reference()) selector_copy.set_reference(jet);
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115 | selector_copy.sift(subjets, kept, rejected);
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116 |
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117 | // gather the info under the form of a PseudoJet
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118 | return _finalise(jet, kept, rejected, ca_optimised);
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119 | }
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120 |
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121 |
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122 | // sets filtered_elements to be all the subjets on which filtering will work
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123 | //
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124 | // return true when the subjets have been optained using teh optimised
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125 | // method for C/A
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126 | bool Filter::_set_filtered_elements(const PseudoJet & jet,
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127 | vector<PseudoJet> & filtered_elements) const {
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128 | // create the recluster instance
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129 | Recluster recluster;
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130 | if ((_Rfilt>=0) || (_Rfiltfunc))
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131 | recluster = Recluster(cambridge_algorithm, (_Rfiltfunc) ? (*_Rfiltfunc)(jet) : _Rfilt, Recluster::keep_all);
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132 | else
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133 | recluster = Recluster(_subjet_def, false, Recluster::keep_all);
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134 |
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135 | // get the subjets
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136 | //JetDefinition subjet_def;
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137 | return recluster.get_new_jets_and_def(jet, filtered_elements);
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138 | }
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139 |
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140 | // gather the information about what is kept and rejected under the
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141 | // form of a PseudoJet with a special ClusterSequenceInfo
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142 | PseudoJet Filter::_finalise(const PseudoJet & /*jet*/,
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143 | vector<PseudoJet> & kept,
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144 | vector<PseudoJet> & rejected,
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145 | bool ca_optimisation_used) const {
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146 | PseudoJet filtered_jet;
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147 |
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148 | if (kept.size()+rejected.size()>0){
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149 | // figure out which recombiner to use
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150 | const JetDefinition::Recombiner &rec = (kept.size()>0)
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151 | ? *(kept[0].associated_cs()->jet_def().recombiner())
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152 | : *(rejected[0].associated_cs()->jet_def().recombiner());
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153 |
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154 | // create an appropriate structure and transfer the info to it
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155 | filtered_jet = join<StructureType>(kept, rec);
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156 | } else {
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157 | filtered_jet = join<StructureType>(kept);
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158 | }
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159 | StructureType *fs = (StructureType*) filtered_jet.structure_non_const_ptr();
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160 | fs->_rejected = rejected;
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161 |
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162 | // if we've used C/A optimisation, we need to get rid of the area
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163 | // information if it comes from a non-explicit-ghost clustering.
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164 | // (because in that case it can be erroneous due the lack of
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165 | // information about empty areas)
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166 | if ((ca_optimisation_used) && (kept.size()+rejected.size()>0)){
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167 | bool has_non_explicit_ghost_area = (kept.size()>0)
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168 | ? (kept[0].has_area() && (!(kept[0].validated_csab()->has_explicit_ghosts())))
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169 | : (rejected[0].has_area() && (!(rejected[0].validated_csab()->has_explicit_ghosts())));
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170 | if (has_non_explicit_ghost_area)
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171 | fs->discard_area();
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172 | }
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173 |
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174 | return filtered_jet;
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175 | }
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176 |
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177 |
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178 | FASTJET_END_NAMESPACE // defined in fastjet/internal/base.hh
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