fastjet::SISConePlugin Class Reference
SISConePlugin is a plugin for fastjet (v2.1 upwards) that provides an interface to the seedless infrared safe cone jet finder by Gregory Soyez and Gavin Salam. More...
#include <SISConePlugin.hh>
Public Types | |
| enum | SplitMergeScale { SM_pt, SM_Et, SM_mt, SM_pttilde } |
| enum for the different split-merge scale choices; Note that order _must_ be the same as in siscone More... | |
Public Member Functions | |
| SISConePlugin (double cone_radius, double overlap_threshold, int n_pass_max=0, double protojet_ptmin=0.0, bool caching=false, SplitMergeScale split_merge_scale=SM_pttilde, double split_merge_stopping_scale=0.0) | |
| Main constructor for the SISCone Plugin class. | |
| SISConePlugin (double cone_radius, double overlap_threshold, int n_pass_max, double protojet_ptmin, bool caching, bool split_merge_on_transverse_mass) | |
| Backwards compatible constructor for the SISCone Plugin class. | |
| SISConePlugin (double cone_radius, double overlap_threshold, int n_pass_max, bool caching) | |
| backwards compatible constructor for the SISCone Plugin class (avoid using this in future). | |
| double | protojet_ptmin () const |
| minimum pt for a protojet to be considered in the split-merge step of the algorithm | |
| double | protojet_or_ghost_ptmin () const |
| return the scale to be passed to SISCone as the protojet_ptmin -- if we have a ghost separation scale that is above the protojet_ptmin, then the ghost_separation_scale becomes the relevant one to use here | |
| SplitMergeScale | split_merge_scale () const |
| indicates scale used in split-merge | |
| void | set_split_merge_scale (SplitMergeScale sms) |
| sets scale used in split-merge | |
| bool | split_merge_on_transverse_mass () const |
| indicates whether the split-merge orders on transverse mass or not. | |
| void | set_split_merge_on_transverse_mass (bool val) |
| bool | split_merge_use_pt_weighted_splitting () const |
| indicates whether the split-merge orders on transverse mass or not. | |
| void | set_split_merge_use_pt_weighted_splitting (bool val) |
| virtual std::string | description () const |
| plugin description | |
| virtual void | run_clustering (ClusterSequence &) const |
| really do the clustering work | |
Protected Member Functions | |
| virtual void | reset_stored_plugin () const |
| call the re-clustering itself | |
Private Attributes | |
| double | _protojet_ptmin |
| SplitMergeScale | _split_merge_scale |
| bool | _use_pt_weighted_splitting |
Static Private Attributes | |
| static std::auto_ptr < SISConePlugin > | stored_plugin |
| static std::auto_ptr < std::vector< PseudoJet > > | stored_particles |
| static std::auto_ptr < siscone::Csiscone > | stored_siscone |
Detailed Description
SISConePlugin is a plugin for fastjet (v2.1 upwards) that provides an interface to the seedless infrared safe cone jet finder by Gregory Soyez and Gavin Salam.SISCone uses geometrical techniques to exhaustively consider all possible distinct cones. It then finds out which ones are stable and sends the result to the Tevatron Run-II type split-merge procedure for overlapping cones.
Four parameters govern the "physics" of the algorithm:
- the cone_radius (this should be self-explanatory!)
- the overlap_threshold is the parameter which dictates how much two jets must overlap (pt_overlap/min(pt1,pt2)) if they are to be merged
- Not all particles are in stable cones in the first round of searching for stable cones; one can therefore optionally have the the jet finder carry out additional passes of searching for stable cones among particles that were in no stable cone in previous passes --- the maximum number of passes carried out is n_pass_max. If this is zero then additional passes are carried out until no new stable cones are found.
- Protojet ptmin: protojets that are below this ptmin (default = 0) are discarded before each iteration of the split-merge loop.
One parameter governs some internal algorithmic shortcuts:
- if "caching" is turned on then the last event clustered by siscone is stored -- if the current event is identical and the cone_radius and n_pass_mass are identical, then the only part of the clustering that needs to be rerun is the split-merge part, leading to significant speed gains; there is a small (O(N) storage and speed) penalty for caching, so it should be kept off (default) if only a single overlap_threshold is used.
The final jets can be accessed by requestion the inclusive_jets(...) from the ClusterSequence object. Note that these PseudoJets have their user_index() set to the index of the pass in which they were found (first pass = 0). NB: This does not currently work for jets that consist of a single particle.
For further information on the details of the algorithm see the SISCone paper, arXiv:0704.0292 [JHEP 0705:086,2007].
For documentation about the implementation, see the siscone/doc/html/index.html file.
Definition at line 67 of file SISConePlugin.hh.
Member Enumeration Documentation
enum for the different split-merge scale choices; Note that order _must_ be the same as in siscone
- Enumerator:
Definition at line 72 of file SISConePlugin.hh.
00072 {SM_pt, 00073 SM_Et, 00074 00075 SM_mt, 00076 00077 SM_pttilde 00078 00079 };
Constructor & Destructor Documentation
| fastjet::SISConePlugin::SISConePlugin | ( | double | cone_radius, | |
| double | overlap_threshold, | |||
| int | n_pass_max = 0, |
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| double | protojet_ptmin = 0.0, |
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| bool | caching = false, |
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| SplitMergeScale | split_merge_scale = SM_pttilde, |
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| double | split_merge_stopping_scale = 0.0 | |||
| ) | [inline] |
Main constructor for the SISCone Plugin class.
Note: wrt version prior to 2.4 this constructor differs in that a the default value has been removed for overlap_threshold. The former has been removed because the old default of 0.5 was found to be unsuitable in high-noise environments; so the user should now explicitly think about the value for this -- we recommend 0.75.
Definition at line 91 of file SISConePlugin.hh.
Referenced by reset_stored_plugin().
00097 { 00098 _cone_radius = cone_radius; 00099 _overlap_threshold = overlap_threshold; 00100 _n_pass_max = n_pass_max; 00101 _protojet_ptmin = protojet_ptmin; 00102 _caching = caching; 00103 _split_merge_scale = split_merge_scale; 00104 _split_merge_stopping_scale = split_merge_stopping_scale; 00105 _ghost_sep_scale = 0.0; 00106 _use_pt_weighted_splitting = false;}
| fastjet::SISConePlugin::SISConePlugin | ( | double | cone_radius, | |
| double | overlap_threshold, | |||
| int | n_pass_max, | |||
| double | protojet_ptmin, | |||
| bool | caching, | |||
| bool | split_merge_on_transverse_mass | |||
| ) | [inline] |
Backwards compatible constructor for the SISCone Plugin class.
Definition at line 110 of file SISConePlugin.hh.
00115 { 00116 _cone_radius = cone_radius; 00117 _overlap_threshold = overlap_threshold; 00118 _n_pass_max = n_pass_max; 00119 _protojet_ptmin = protojet_ptmin; 00120 _caching = caching; 00121 _split_merge_stopping_scale = 0.0; 00122 _split_merge_scale = split_merge_on_transverse_mass ? SM_mt : SM_pttilde; 00123 _ghost_sep_scale = 0.0;}
| fastjet::SISConePlugin::SISConePlugin | ( | double | cone_radius, | |
| double | overlap_threshold, | |||
| int | n_pass_max, | |||
| bool | caching | |||
| ) | [inline] |
backwards compatible constructor for the SISCone Plugin class (avoid using this in future).
Definition at line 127 of file SISConePlugin.hh.
00130 { 00131 _cone_radius = cone_radius; 00132 _overlap_threshold = overlap_threshold; 00133 _n_pass_max = n_pass_max; 00134 _protojet_ptmin = 0.0; 00135 _caching = caching; 00136 _split_merge_scale = SM_mt; 00137 _split_merge_stopping_scale = 0.0; 00138 _ghost_sep_scale = 0.0; 00139 _use_pt_weighted_splitting = false;}
Member Function Documentation
| string fastjet::SISConePlugin::description | ( | ) | const [virtual] |
plugin description
Implements fastjet::SISConeBasePlugin.
Definition at line 36 of file SISConePlugin.cc.
References fastjet::SISConeBasePlugin::_split_merge_stopping_scale, fastjet::SISConeBasePlugin::_use_jet_def_recombiner, _use_pt_weighted_splitting, fastjet::SISConeBasePlugin::caching(), fastjet::SISConeBasePlugin::cone_radius(), fastjet::SISConeBasePlugin::n_pass_max(), fastjet::SISConeBasePlugin::overlap_threshold(), protojet_ptmin(), and split_merge_scale().
00036 { 00037 ostringstream desc; 00038 00039 const string on = "on"; 00040 const string off = "off"; 00041 00042 string sm_scale_string = "split-merge uses " + 00043 split_merge_scale_name(Esplit_merge_scale(split_merge_scale())); 00044 00045 desc << "SISCone jet algorithm with " ; 00046 desc << "cone_radius = " << cone_radius () << ", "; 00047 desc << "overlap_threshold = " << overlap_threshold () << ", "; 00048 desc << "n_pass_max = " << n_pass_max () << ", "; 00049 desc << "protojet_ptmin = " << protojet_ptmin() << ", "; 00050 desc << sm_scale_string << ", "; 00051 desc << "caching turned " << (caching() ? on : off); 00052 desc << ", SM stop scale = " << _split_merge_stopping_scale; 00053 00054 // add a note to the description if we use the pt-weighted splitting 00055 if (_use_pt_weighted_splitting){ 00056 desc << ", using pt-weighted splitting"; 00057 } 00058 00059 if (_use_jet_def_recombiner){ 00060 desc << ", using jet-definition's own recombiner"; 00061 } 00062 00063 // create a fake siscone object so that we can find out more about it 00064 Csiscone siscone; 00065 if (siscone.merge_identical_protocones) { 00066 desc << ", and (IR unsafe) merge_indentical_protocones=true" ; 00067 } 00068 00069 desc << ", SISCone code v" << siscone_version(); 00070 00071 return desc.str(); 00072 }
| double fastjet::SISConePlugin::protojet_or_ghost_ptmin | ( | ) | const [inline] |
return the scale to be passed to SISCone as the protojet_ptmin -- if we have a ghost separation scale that is above the protojet_ptmin, then the ghost_separation_scale becomes the relevant one to use here
Definition at line 149 of file SISConePlugin.hh.
Referenced by run_clustering().
00149 {return std::max(_protojet_ptmin, 00150 _ghost_sep_scale);}
| double fastjet::SISConePlugin::protojet_ptmin | ( | ) | const [inline] |
minimum pt for a protojet to be considered in the split-merge step of the algorithm
Definition at line 143 of file SISConePlugin.hh.
Referenced by description().
00143 {return _protojet_ptmin ;}
| void fastjet::SISConePlugin::reset_stored_plugin | ( | ) | const [protected, virtual] |
call the re-clustering itself
Implements fastjet::SISConeBasePlugin.
Definition at line 210 of file SISConePlugin.cc.
References SISConePlugin(), and stored_plugin.
Referenced by run_clustering().
00210 { 00211 stored_plugin.reset( new SISConePlugin(*this)); 00212 }
| void fastjet::SISConePlugin::run_clustering | ( | ClusterSequence & | ) | const [virtual] |
really do the clustering work
Implements fastjet::SISConeBasePlugin.
Definition at line 76 of file SISConePlugin.cc.
References fastjet::SISConeBaseExtras::_jet_def_plugin, fastjet::SISConeBaseExtras::_most_ambiguous_split, fastjet::SISConeBaseExtras::_pass, fastjet::SISConeBaseExtras::_protocones, fastjet::SISConeBasePlugin::_split_merge_stopping_scale, fastjet::SISConeBasePlugin::_use_jet_def_recombiner, _use_pt_weighted_splitting, fastjet::SISConeBasePlugin::caching(), fastjet::SISConeBasePlugin::cone_radius(), fastjet::PseudoJet::E(), fastjet::SISConeBasePlugin::ghost_separation_scale(), fastjet::have_same_momentum(), fastjet::ClusterSequence::jets(), fastjet::SISConeBasePlugin::n_pass_max(), fastjet::SISConeBasePlugin::overlap_threshold(), fastjet::ClusterSequence::plugin_associate_extras(), fastjet::ClusterSequence::plugin_record_iB_recombination(), fastjet::ClusterSequence::plugin_record_ij_recombination(), protojet_or_ghost_ptmin(), fastjet::PseudoJet::px(), fastjet::PseudoJet::py(), fastjet::PseudoJet::pz(), reset_stored_plugin(), fastjet::PseudoJet::set_user_index(), split_merge_scale(), stored_particles, stored_plugin, and stored_siscone.
00076 { 00077 00078 Csiscone local_siscone; 00079 Csiscone * siscone; 00080 00081 unsigned n = clust_seq.jets().size(); 00082 00083 bool new_siscone = true; // by default we'll be running it 00084 00085 if (caching()) { 00086 00087 // Establish if we have a cached run with the same R, npass and 00088 // particles. If not then do any tidying up / reallocation that's 00089 // necessary for the next round of caching, otherwise just set 00090 // relevant pointers so that we can reuse and old run. 00091 if (stored_siscone.get() != 0) { 00092 new_siscone = !(stored_plugin->cone_radius() == cone_radius() 00093 && stored_plugin->n_pass_max() == n_pass_max() 00094 && stored_particles->size() == n); 00095 if (!new_siscone) { 00096 for(unsigned i = 0; i < n; i++) { 00097 // only check momentum because indices will be correctly dealt 00098 // with anyway when extracting the clustering order. 00099 new_siscone |= !have_same_momentum(clust_seq.jets()[i], 00100 (*stored_particles)[i]); 00101 } 00102 } 00103 } 00104 00105 // allocate the new siscone, etc., if need be 00106 if (new_siscone) { 00107 stored_siscone .reset( new Csiscone ); 00108 stored_particles.reset( new std::vector<PseudoJet>(clust_seq.jets())); 00109 reset_stored_plugin(); 00110 } 00111 00112 siscone = stored_siscone.get(); 00113 } else { 00114 siscone = &local_siscone; 00115 } 00116 00117 // make sure stopping scale is set in siscone 00118 siscone->SM_var2_hardest_cut_off = _split_merge_stopping_scale*_split_merge_stopping_scale; 00119 00120 // set the specific parameters 00121 // when running with ghosts for passive areas, do not put the 00122 // ghosts into the stable-cone search (not relevant) 00123 siscone->stable_cone_soft_pt2_cutoff = ghost_separation_scale() 00124 * ghost_separation_scale(); 00125 // set the type of splitting we want (default=std one, true->pt-weighted split) 00126 siscone->set_pt_weighted_splitting(_use_pt_weighted_splitting); 00127 00128 if (new_siscone) { 00129 // transfer fastjet initial particles into the siscone type 00130 std::vector<Cmomentum> siscone_momenta(n); 00131 for(unsigned i = 0; i < n; i++) { 00132 const PseudoJet & p = clust_seq.jets()[i]; // shorthand 00133 siscone_momenta[i] = Cmomentum(p.px(), p.py(), p.pz(), p.E()); 00134 } 00135 00136 // run the jet finding 00137 //cout << "plg sms: " << split_merge_scale() << endl; 00138 siscone->compute_jets(siscone_momenta, cone_radius(), overlap_threshold(), 00139 n_pass_max(), protojet_or_ghost_ptmin(), 00140 Esplit_merge_scale(split_merge_scale())); 00141 } else { 00142 // rerun the jet finding 00143 // just run the overlap part of the jets. 00144 //cout << "plg rcmp sms: " << split_merge_scale() << endl; 00145 siscone->recompute_jets(overlap_threshold(), protojet_or_ghost_ptmin(), 00146 Esplit_merge_scale(split_merge_scale())); 00147 } 00148 00149 // extract the jets [in reverse order -- to get nice ordering in pt at end] 00150 int njet = siscone->jets.size(); 00151 00152 // allocate space for the extras object 00153 SISConeExtras * extras = new SISConeExtras(n); 00154 00155 for (int ijet = njet-1; ijet >= 0; ijet--) { 00156 const Cjet & jet = siscone->jets[ijet]; // shorthand 00157 00158 // Successively merge the particles that make up the cone jet 00159 // until we have all particles in it. Start off with the zeroth 00160 // particle. 00161 int jet_k = jet.contents[0]; 00162 for (unsigned ipart = 1; ipart < jet.contents.size(); ipart++) { 00163 // take the last result of the merge 00164 int jet_i = jet_k; 00165 // and the next element of the jet 00166 int jet_j = jet.contents[ipart]; 00167 // and merge them (with a fake dij) 00168 double dij = 0.0; 00169 00170 if (_use_jet_def_recombiner) { 00171 clust_seq.plugin_record_ij_recombination(jet_i, jet_j, dij, jet_k); 00172 } else { 00173 // create the new jet by hand so that we can adjust its user index 00174 PseudoJet newjet = clust_seq.jets()[jet_i] + clust_seq.jets()[jet_j]; 00175 // set the user index to be the pass in which the jet was discovered 00176 newjet.set_user_index(jet.pass); 00177 clust_seq.plugin_record_ij_recombination(jet_i, jet_j, dij, newjet, jet_k); 00178 } 00179 00180 } 00181 00182 // we have merged all the jet's particles into a single object, so now 00183 // "declare" it to be a beam (inclusive) jet. 00184 // [NB: put a sensible looking d_iB just to be nice...] 00185 double d_iB = clust_seq.jets()[jet_k].perp2(); 00186 clust_seq.plugin_record_iB_recombination(jet_k, d_iB); 00187 00188 // now record the pass of the jet in the extras object 00189 extras->_pass[clust_seq.jets()[jet_k].cluster_hist_index()] = jet.pass; 00190 } 00191 00192 // now copy the list of protocones into an "extras" objects 00193 for (unsigned ipass = 0; ipass < siscone->protocones_list.size(); ipass++) { 00194 for (unsigned ipc = 0; ipc < siscone->protocones_list[ipass].size(); ipc++) { 00195 PseudoJet protocone(siscone->protocones_list[ipass][ipc]); 00196 protocone.set_user_index(ipass); 00197 extras->_protocones.push_back(protocone); 00198 } 00199 } 00200 extras->_most_ambiguous_split = siscone->most_ambiguous_split; 00201 00202 // tell it what the jet definition was 00203 extras->_jet_def_plugin = this; 00204 00205 // give the extras object to the cluster sequence. 00206 clust_seq.plugin_associate_extras(std::auto_ptr<ClusterSequence::Extras>(extras)); 00207 }
| void fastjet::SISConePlugin::set_split_merge_on_transverse_mass | ( | bool | val | ) | [inline] |
Definition at line 160 of file SISConePlugin.hh.
00160 { 00161 _split_merge_scale = val ? SM_mt : SM_pt;}
| void fastjet::SISConePlugin::set_split_merge_scale | ( | SplitMergeScale | sms | ) | [inline] |
sets scale used in split-merge
Definition at line 155 of file SISConePlugin.hh.
00155 {_split_merge_scale = sms;}
| void fastjet::SISConePlugin::set_split_merge_use_pt_weighted_splitting | ( | bool | val | ) | [inline] |
| bool fastjet::SISConePlugin::split_merge_on_transverse_mass | ( | ) | const [inline] |
indicates whether the split-merge orders on transverse mass or not.
retained for backwards compatibility with 2.1.0b3
Definition at line 159 of file SISConePlugin.hh.
00159 {return _split_merge_scale == SM_mt ;}
| SplitMergeScale fastjet::SISConePlugin::split_merge_scale | ( | ) | const [inline] |
indicates scale used in split-merge
Definition at line 153 of file SISConePlugin.hh.
Referenced by description(), and run_clustering().
00153 {return _split_merge_scale;}
| bool fastjet::SISConePlugin::split_merge_use_pt_weighted_splitting | ( | ) | const [inline] |
indicates whether the split-merge orders on transverse mass or not.
retained for backwards compatibility with 2.1.0b3
Definition at line 165 of file SISConePlugin.hh.
00165 {return _use_pt_weighted_splitting;}
Member Data Documentation
double fastjet::SISConePlugin::_protojet_ptmin [private] |
Definition at line 177 of file SISConePlugin.hh.
Definition at line 178 of file SISConePlugin.hh.
bool fastjet::SISConePlugin::_use_pt_weighted_splitting [private] |
std::auto_ptr< std::vector< PseudoJet > > fastjet::SISConePlugin::stored_particles [static, private] |
std::auto_ptr< SISConePlugin > fastjet::SISConePlugin::stored_plugin [static, private] |
Definition at line 184 of file SISConePlugin.hh.
Referenced by reset_stored_plugin(), and run_clustering().
std::auto_ptr< Csiscone > fastjet::SISConePlugin::stored_siscone [static, private] |
The documentation for this class was generated from the following files:
- plugins/SISCone/fastjet/SISConePlugin.hh
- plugins/SISCone/SISConePlugin.cc
