1 | #ifndef __SISCONEPLUGIN_HH__ |
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2 | #define __SISCONEPLUGIN_HH__ |
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3 | |
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4 | #include "SISConeBasePlugin.hh" |
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5 | |
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6 | // forward declaration of the siscone classes we'll need |
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7 | namespace siscone{ |
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8 | class Csiscone; |
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9 | } |
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10 | |
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11 | |
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12 | FASTJET_BEGIN_NAMESPACE // defined in fastjet/internal/base.hh |
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13 | |
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14 | //---------------------------------------------------------------------- |
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15 | // |
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16 | /// @ingroup plugins |
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17 | /// \class SISConePlugin |
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18 | /// Implementation of the SISCone algorithm (plugin for fastjet v2.1 upwards) |
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19 | /// |
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20 | /// SISConePlugin is a plugin for fastjet (v2.1 upwards) that provides |
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21 | /// an interface to the seedless infrared safe cone jet finder by |
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22 | /// Gregory Soyez and Gavin Salam. |
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23 | /// |
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24 | /// SISCone uses geometrical techniques to exhaustively consider all |
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25 | /// possible distinct cones. It then finds out which ones are stable |
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26 | /// and sends the result to the Tevatron Run-II type split-merge |
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27 | /// procedure for overlapping cones. |
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28 | /// |
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29 | /// Four parameters govern the "physics" of the algorithm: |
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30 | /// |
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31 | /// - the cone_radius (this should be self-explanatory!) |
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32 | /// |
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33 | /// - the overlap_threshold is the parameter which dictates how much |
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34 | /// two jets must overlap (pt_overlap/min(pt1,pt2)) if they are to be |
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35 | /// merged |
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36 | /// |
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37 | /// - Not all particles are in stable cones in the first round of |
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38 | /// searching for stable cones; one can therefore optionally have the |
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39 | /// the jet finder carry out additional passes of searching for |
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40 | /// stable cones among particles that were in no stable cone in |
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41 | /// previous passes --- the maximum number of passes carried out is |
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42 | /// n_pass_max. If this is zero then additional passes are carried |
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43 | /// out until no new stable cones are found. |
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44 | /// |
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45 | /// - Protojet ptmin: protojets that are below this ptmin |
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46 | /// (default = 0) are discarded before each iteration of the |
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47 | /// split-merge loop. |
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48 | /// |
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49 | /// One parameter governs some internal algorithmic shortcuts: |
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50 | /// |
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51 | /// - if "caching" is turned on then the last event clustered by |
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52 | /// siscone is stored -- if the current event is identical and the |
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53 | /// cone_radius and n_pass_mass are identical, then the only part of |
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54 | /// the clustering that needs to be rerun is the split-merge part, |
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55 | /// leading to significant speed gains; there is a small (O(N) storage |
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56 | /// and speed) penalty for caching, so it should be kept off |
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57 | /// (default) if only a single overlap_threshold is used. |
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58 | /// |
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59 | /// The final jets can be accessed by requestion the |
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60 | /// inclusive_jets(...) from the ClusterSequence object. Note that |
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61 | /// these PseudoJets have their user_index() set to the index of the |
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62 | /// pass in which they were found (first pass = 0). NB: This does not |
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63 | /// currently work for jets that consist of a single particle. |
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64 | /// |
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65 | /// For further information on the details of the algorithm see the |
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66 | /// SISCone paper, arXiv:0704.0292 [JHEP 0705:086,2007]. |
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67 | /// |
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68 | /// For documentation about the implementation, see the |
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69 | /// siscone/doc/html/index.html file. |
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70 | // |
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71 | class SISConePlugin : public SISConeBasePlugin{ |
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72 | public: |
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73 | |
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74 | /// enum for the different split-merge scale choices; |
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75 | /// Note that order _must_ be the same as in siscone |
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76 | enum SplitMergeScale {SM_pt, ///< transverse momentum (E-scheme), IR unsafe |
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77 | SM_Et, ///< transverse energy (E-scheme), not long. boost invariant |
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78 | ///< original run-II choice [may not be implemented] |
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79 | SM_mt, ///< transverse mass (E-scheme), IR safe except |
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80 | ///< in decays of two identical narrow heavy particles |
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81 | SM_pttilde ///< pt-scheme pt = \sum_{i in jet} |p_{ti}|, should |
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82 | ///< be IR safe in all cases |
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83 | }; |
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84 | |
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85 | |
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86 | /// Main constructor for the SISCone Plugin class. |
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87 | /// |
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88 | /// Note: wrt version prior to 2.4 this constructor differs in that a |
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89 | /// the default value has been removed for overlap_threshold. The |
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90 | /// former has been removed because the old default of 0.5 was found |
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91 | /// to be unsuitable in high-noise environments; so the user should |
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92 | /// now explicitly think about the value for this -- we recommend |
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93 | /// 0.75. |
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94 | /// |
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95 | SISConePlugin (double cone_radius_in, |
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96 | double overlap_threshold_in, |
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97 | int n_pass_max_in = 0, |
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98 | double protojet_ptmin_in = 0.0, |
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99 | bool caching_in = false, |
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100 | SplitMergeScale split_merge_scale_in = SM_pttilde, |
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101 | double split_merge_stopping_scale_in = 0.0){ |
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102 | _cone_radius = cone_radius_in; |
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103 | _overlap_threshold = overlap_threshold_in; |
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104 | _n_pass_max = n_pass_max_in; |
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105 | _protojet_ptmin = protojet_ptmin_in; |
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106 | _caching = caching_in; |
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107 | _split_merge_scale = split_merge_scale_in; |
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108 | _split_merge_stopping_scale = split_merge_stopping_scale_in; |
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109 | _ghost_sep_scale = 0.0; |
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110 | _use_pt_weighted_splitting = false;} |
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111 | |
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112 | |
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113 | /// Backwards compatible constructor for the SISCone Plugin class |
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114 | SISConePlugin (double cone_radius_in, |
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115 | double overlap_threshold_in, |
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116 | int n_pass_max_in, |
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117 | double protojet_ptmin_in, |
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118 | bool caching_in, |
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119 | bool split_merge_on_transverse_mass_in){ |
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120 | _cone_radius = cone_radius_in; |
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121 | _overlap_threshold = overlap_threshold_in; |
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122 | _n_pass_max = n_pass_max_in; |
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123 | _protojet_ptmin = protojet_ptmin_in; |
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124 | _caching = caching_in; |
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125 | _split_merge_stopping_scale = 0.0; |
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126 | _split_merge_scale = split_merge_on_transverse_mass_in ? SM_mt : SM_pttilde; |
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127 | _ghost_sep_scale = 0.0;} |
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128 | |
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129 | /// backwards compatible constructor for the SISCone Plugin class |
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130 | /// (avoid using this in future). |
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131 | SISConePlugin (double cone_radius_in, |
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132 | double overlap_threshold_in, |
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133 | int n_pass_max_in, |
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134 | bool caching_in) { |
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135 | _cone_radius = cone_radius_in; |
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136 | _overlap_threshold = overlap_threshold_in; |
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137 | _n_pass_max = n_pass_max_in; |
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138 | _protojet_ptmin = 0.0; |
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139 | _caching = caching_in; |
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140 | _split_merge_scale = SM_mt; |
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141 | _split_merge_stopping_scale = 0.0; |
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142 | _ghost_sep_scale = 0.0; |
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143 | _use_pt_weighted_splitting = false;} |
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144 | |
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145 | /// minimum pt for a protojet to be considered in the split-merge step |
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146 | /// of the algorithm |
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147 | double protojet_ptmin () const {return _protojet_ptmin ;} |
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148 | |
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149 | /// return the scale to be passed to SISCone as the protojet_ptmin |
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150 | /// -- if we have a ghost separation scale that is above the |
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151 | /// protojet_ptmin, then the ghost_separation_scale becomes the |
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152 | /// relevant one to use here |
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153 | double protojet_or_ghost_ptmin () const {return std::max(_protojet_ptmin, |
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154 | _ghost_sep_scale);} |
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155 | |
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156 | /// indicates scale used in split-merge |
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157 | SplitMergeScale split_merge_scale() const {return _split_merge_scale;} |
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158 | /// sets scale used in split-merge |
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159 | void set_split_merge_scale(SplitMergeScale sms) {_split_merge_scale = sms;} |
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160 | |
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161 | /// indicates whether the split-merge orders on transverse mass or not. |
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162 | /// retained for backwards compatibility with 2.1.0b3 |
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163 | bool split_merge_on_transverse_mass() const {return _split_merge_scale == SM_mt ;} |
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164 | void set_split_merge_on_transverse_mass(bool val) { |
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165 | _split_merge_scale = val ? SM_mt : SM_pt;} |
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166 | |
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167 | /// indicates whether the split-merge orders on transverse mass or not. |
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168 | /// retained for backwards compatibility with 2.1.0b3 |
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169 | bool split_merge_use_pt_weighted_splitting() const {return _use_pt_weighted_splitting;} |
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170 | void set_split_merge_use_pt_weighted_splitting(bool val) { |
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171 | _use_pt_weighted_splitting = val;} |
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172 | |
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173 | // the things that are required by base class |
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174 | virtual std::string description () const; |
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175 | virtual void run_clustering(ClusterSequence &) const ; |
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176 | |
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177 | protected: |
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178 | virtual void reset_stored_plugin() const; |
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179 | |
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180 | private: |
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181 | double _protojet_ptmin; |
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182 | SplitMergeScale _split_merge_scale; |
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183 | |
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184 | bool _use_pt_weighted_splitting; |
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185 | |
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186 | // part needed for the cache |
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187 | // variables for caching the results and the input |
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188 | static std::auto_ptr<SISConePlugin > stored_plugin; |
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189 | static std::auto_ptr<std::vector<PseudoJet> > stored_particles; |
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190 | static std::auto_ptr<siscone::Csiscone > stored_siscone; |
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191 | }; |
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192 | |
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193 | |
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194 | //====================================================================== |
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195 | /// @ingroup extra_info |
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196 | /// \class SISConeExtras |
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197 | /// Class that provides extra information about a SISCone clustering |
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198 | class SISConeExtras : public SISConeBaseExtras { |
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199 | public: |
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200 | /// constructor |
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201 | // it just initialises the pass information |
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202 | SISConeExtras(int nparticles) |
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203 | : SISConeBaseExtras(nparticles){} |
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204 | |
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205 | /// access to the siscone jet def plugin (more convenient than |
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206 | /// getting it from the original jet definition, because here it's |
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207 | /// directly of the right type (rather than the base type) |
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208 | const SISConePlugin* jet_def_plugin() const { |
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209 | return dynamic_cast<const SISConePlugin*>(_jet_def_plugin); |
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210 | } |
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211 | |
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212 | private: |
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213 | // let us be written to by SISConePlugin |
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214 | friend class SISConePlugin; |
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215 | }; |
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216 | |
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217 | FASTJET_END_NAMESPACE // defined in fastjet/internal/base.hh |
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218 | |
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219 | #endif // __SISCONEPLUGIN_HH__ |
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220 | |
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