FastJet  3.4.0
SISConeBasePlugin.hh
1 #ifndef __SISCONEBASEPLUGIN_HH__
2 #define __SISCONEBASEPLUGIN_HH__
3 
4 #include "fastjet/JetDefinition.hh"
5 #include "fastjet/ClusterSequence.hh"
6 #include <vector>
7 #include <memory>
8 #include <cmath>
9 
10 #include <sstream>
11 
12 // questionable whether this should be in fastjet namespace or not...
13 FASTJET_BEGIN_NAMESPACE // defined in fastjet/internal/base.hh
14 
15 //----------------------------------------------------------------------
16 //
17 /// \if internal_doc
18 /// @ingroup internal
19 /// \class SISConeBasePlugin
20 /// Implementation of the SISCone algorithm, base class (plugin for fastjet v2.1 upwards)
21 ///
22 /// SISConeBasePlugin is a plugin for fastjet (v2.1 upwards) that
23 /// provides a base interface to SISCone-type cone jet finder by
24 /// Gregory Soyez and Gavin Salam.
25 ///
26 /// This is a purely virtual class that needs to be overloaded
27 /// for the specific implementations of SISCone (i.e. regular or
28 /// spherical as of July 16th 2008).
29 ///
30 /// any derived plugin MUST overload the following methods:
31 /// description()
32 /// run_siscone_clustering()
33 /// reset_stored_plugin()
34 ///
35 /// For further details, see the derived plugins or
36 /// http://projects.hepforge.com/siscone
37 ///
38 /// \endif
39 //
40 class SISConeBasePlugin : public JetDefinition::Plugin {
41 public:
42  /// default ctor
43  SISConeBasePlugin (){
44  _use_jet_def_recombiner = false;
45  set_progressive_removal(false);
46  }
47 
48  /// copy constructor
49  SISConeBasePlugin (const SISConeBasePlugin & plugin) {
50  *this = plugin;
51  }
52 
53  /// set whether to use SISCone with progressive removal instead of
54  /// the default split_merge step.
55  ///
56  /// If progressive removal is enabled, the following SISCone
57  /// variables are not used:
58  ///
59  /// - overlap_threshold
60  /// - caching
61  /// - split_merge_stopping_scale
62  ///
63  /// The split_merge_scale choice is reinterpreted as the ordering
64  /// variable for progressive removal. It is also possible for the
65  /// user to supply his/her own function for the scale that orders
66  /// progressive removal, with set_user_scale(...)
67  void set_progressive_removal(bool progressive_removal_in=true){
68  _progressive_removal = progressive_removal_in;
69  }
70 
71  /// returns true if progressive_removal is enabled
72  bool progressive_removal() const{ return _progressive_removal;}
73 
74  /// the cone radius
75  double cone_radius () const {return _cone_radius ;}
76 
77  /// Fraction of overlap energy in a jet above which jets are merged
78  /// and below which jets are split.
79  double overlap_threshold () const {return _overlap_threshold ;}
80 
81  /// the maximum number of passes of stable-cone searching (<=0 is same
82  /// as infinity).
83  int n_pass_max () const {return _n_pass_max ;}
84 
85  /// set the "split_merge_stopping_scale": if the scale variable for
86  /// all protojets is below this, then stop the split-merge procedure
87  /// and keep only those jets found so far. This is useful in
88  /// determination of areas of hard jets because it can be used to
89  /// avoid running the split-merging on the pure ghost-part of the
90  /// event.
91  void set_split_merge_stopping_scale(double scale) {
92  _split_merge_stopping_scale = scale;}
93 
94  /// return the value of the split_merge_stopping_scale (see
95  /// set_split_merge_stopping_scale(...) for description)
96  double split_merge_stopping_scale() {return _split_merge_stopping_scale;}
97 
98  /// allow the user to decide if one uses the jet_def's own recombination scheme
99  void set_use_jet_def_recombiner(bool choice) {_use_jet_def_recombiner = choice;}
100 
101  /// indicate if the jet_def's recombination scheme is being used
102  bool use_jet_def_recombiner() const {return _use_jet_def_recombiner;}
103 
104  /// indicates whether caching is turned on or not.
105  bool caching() const {return _caching ;}
106 
107  /// the plugin mechanism's standard way of accessing the jet radius
108  virtual double R() const {return cone_radius();}
109 
110  /// return true since there is specific support for the measurement
111  /// of passive areas, in the sense that areas determined from all
112  /// particles below the ghost separation scale will be a passive
113  /// area.
114  virtual bool supports_ghosted_passive_areas() const {
115  return true;
116  }
117 
118  /// set the ghost separation scale for passive area determinations
119  /// _just_ in the next run (strictly speaking that makes the routine
120  /// a non const, so related internal info must be stored as a mutable)
121  virtual void set_ghost_separation_scale(double scale) const {
122  _ghost_sep_scale = scale;
123  }
124 
125  virtual double ghost_separation_scale() const {
126  return _ghost_sep_scale;
127  }
128 
129  // user-defined scale for progressive removal
130  //------------------------------------------------------------
131 
132  /// \class UserScaleBase
133  /// base class for user-defined ordering of stable cones (used for
134  /// prorgessive removal)
135  ///
136  /// derived classes have to implement the () operator that returns
137  /// the scale associated with a given jet.
138  ///
139  /// It is also highly recommended to implement the is_larger()
140  /// method whenever possible, in order to avoid rounding issues
141  /// known to lead to possible infrared unsafeties.
142  ///
143  /// The jets that are passed to this class will carry the structure
144  /// of type SISConePlugin::StructureType which allows to retreive
145  /// easily the following information:
146  ///
147  /// vector<PseudoJet> constituents = jet.constituents();
148  /// unsigned int n_constituents = jet.structure_of<SISConePlugin::UserScaleBase>().size();
149  /// int index = jet.structure_of<SISConePlugin::UserScaleBase>().constituent_index(index i);
150  /// const PseudoJet & p = jet.structure_of<SISConePlugin::UserScaleBase>().constituent(index i);
151  /// double scalar_pt = jet.structure_of<SISConePlugin::UserScaleBase>().pt_tilde();
152  ///
153  /// see SISConePlugin::StructureType below for further details
154  class UserScaleBase : public FunctionOfPseudoJet<double>{
155  public:
156  /// empty virtual dtor
157  virtual ~UserScaleBase(){}
158 
159  /// returns the scale associated with a given jet
160  ///
161  /// "progressive removal" iteratively removes the stable cone with
162  /// the largest scale
163  virtual double result(const PseudoJet & jet) const = 0;
164 
165  /// returns true when the scale associated with jet a is larger than
166  /// the scale associated with jet b
167  ///
168  /// By default this does a simple direct comparison but it can be
169  /// overloaded for higher precision [recommended if possible]
170  virtual bool is_larger(const PseudoJet & a, const PseudoJet & b) const;
171 
172  class StructureType; // defined below
173  };
174 
175  // template class derived from UserScaleBase::StryctureType that
176  // works for both SISCone jet classes
177  // implemented below
178  template<class Tjet>
180 
181  /// set a user-defined scale for stable-cone ordering in
182  /// progressive removal
183  void set_user_scale(const UserScaleBase *user_scale_in){ _user_scale = user_scale_in;}
184 
185  /// returns the user-defined scale in use (0 if none)
186  const UserScaleBase * user_scale() const{ return _user_scale;}
187 
188 
189  // the things that one MUST overload required by base class
190  //---------------------------------------------------------
191 
192  /// plugin description
193  virtual std::string description () const =0;
194 
195  /// really do the clustering work
196  virtual void run_clustering(ClusterSequence &) const = 0;
197 
198 protected:
199  double _cone_radius, _overlap_threshold;
200  int _n_pass_max;
201  bool _caching;//, _split_merge_on_transverse_mass;
202  double _split_merge_stopping_scale;
203  bool _use_jet_def_recombiner;
204  bool _progressive_removal;
205 
206  mutable double _ghost_sep_scale;
207 
208  // the part that HAS to be overloaded
209  /// call the re-clustering itself
210  virtual void reset_stored_plugin() const =0;
211 
212  const UserScaleBase * _user_scale;
213 
214 };
215 
216 
217 //======================================================================
218 /// @ingroup extra_info
219 /// \class SISConeBaseExtras
220 /// Class that provides extra information about a SISCone clustering
221 ///
222 /// This is only the base class that the "regular" and "spherical"
223 /// implementations of SISCone will have to overload. The only thing
224 /// that needs to be done for the derived classes is to define
225 /// '_jet_def_plugin', implement
226 /// jet_def_plugin();
227 /// and add the corresponding plugin class as a friend
229 public:
230 
231  /// constructor
232  // it just initialises the pass information
233  SISConeBaseExtras(int nparticles) : _pass(nparticles*2,-1) {}
234 
235  /// purely virtual destructor
236  inline virtual ~SISConeBaseExtras()=0;
237 
238  /// returns a reference to the vector of stable cones (aka protocones)
239  const std::vector<PseudoJet> & stable_cones() const {return _protocones;}
240 
241  /// an old name for getting the vector of stable cones (aka protocones)
242  const std::vector<PseudoJet> & protocones() const {return _protocones;}
243 
244  /// return the # of the pass at which a given jet was found; will
245  /// return -1 if the pass is invalid
246  int pass(const PseudoJet & jet) const {return _pass[jet.cluster_hist_index()];}
247 
248  /// return a brief summary of the contents of the extras object
249  /// (specifically, the number of protocones.
250  std::string description() const{
251  std::ostringstream ostr;
252  ostr << "This SISCone clustering found " << protocones().size()
253  << " stable protocones";
254  return ostr.str();
255  };
256 
257  /// return the smallest difference in squared distance encountered
258  /// during splitting between a particle and two overlapping
259  /// protojets.
260  inline double most_ambiguous_split() const {return _most_ambiguous_split;}
261 
262 protected:
263  std::vector<PseudoJet> _protocones;
264  std::vector<int> _pass;
265  double _most_ambiguous_split;
266  const SISConeBasePlugin * _jet_def_plugin;
267 };
268 
269 /// give the destructor its required implementation
270 inline SISConeBaseExtras::~SISConeBaseExtras(){}
271 
272 //----------------------------------------------------------------------
273 // implementation of the structure type associated with the UserScaleBase class
274 
275 /// \class SISConeBasePlugin::UserScaleBase::StructureType
276 /// the structure that allows to store the information contained
277 /// into a siscone::Cjet (built internally in SISCone from a stable
278 /// cone) into a PseudoJet
280 public:
281  /// base ctor (constructed from a ClusterSequence tin order to have
282  /// access to the initial particles
284  : _cs(cs){}
285 
286  /// empty virtual dtor
287  virtual ~StructureType(){}
288 
289  //--------------------------------------------------
290  // members inherited from the base class
291  /// the textual descripotion
292  virtual std::string description() const{
293  return "PseudoJet wrapping a siscone jet from a stable cone";
294  }
295 
296  /// this structure has constituents
297  virtual bool has_constituents() const {return true;}
298 
299  /// retrieve the constituents
300  ///
301  /// if you simply need to iterate over the constituents, it will be
302  /// faster to access them via constituent(i)
303  virtual std::vector<PseudoJet> constituents(const PseudoJet & /*reference*/) const{
304  std::vector<PseudoJet> constits;
305  constits.reserve(size());
306  for (unsigned int i=0; i<size();i++)
307  constits.push_back(constituent(i));
308  return constits;
309  }
310 
311  //--------------------------------------------------
312  // additional information relevant for this structure
313 
314  /// returns the number of constituents
315  virtual unsigned int size() const = 0;
316 
317  /// returns the index (in the original particle list) of the ith
318  /// constituent
319  virtual int constituent_index(unsigned int i) const = 0;
320 
321  /// returns the ith constituent (as a PseusoJet)
322  const PseudoJet & constituent(unsigned int i) const{
323  return _cs.jets()[constituent_index(i)];
324  }
325 
326  // /// returns the scalar pt of this stable cone
327  // virtual double pt_tilde() const = 0;
328 
329  /// returns the sm_var2 (signed ordering variable squared) for this stable cone
330  virtual double ordering_var2() const = 0;
331 
332 protected:
333  const ClusterSequence &_cs; ///< a reference to the CS (for access to the particles)
334 };
335 
336 
337 ///@ingroup internal
338 /// template class derived from UserScaleBase::StryctureType that
339 /// works for both SISCone jet classes
340 /// implemented below
341 template<class Tjet>
343 public:
344  UserScaleBaseStructureType(const Tjet &jet, const ClusterSequence &cs)
345  : UserScaleBase::StructureType(cs), _jet(jet){}
346 
347  /// empty virtual dtor
349 
350  //--------------------------------------------------
351  // additional information relevant for this structure
352 
353  /// returns the number of constituents
354  virtual unsigned int size() const{
355  return _jet.n;
356  }
357 
358  /// returns the index (in the original particle list) of the ith
359  /// constituent
360  virtual int constituent_index(unsigned int i) const{
361  return _jet.contents[i];
362  }
363 
364  // /// returns the scalar pt of this stable cone
365  // virtual double pt_tilde() const{
366  // return _jet.pt_tilde;
367  // }
368 
369  /// returns the sm_var2 (signed ordering variable squared) for this stable cone
370  virtual double ordering_var2() const{
371  return _jet.sm_var2;
372  }
373 
374 protected:
375  const Tjet &_jet; ///< a reference to the internal jet in SISCone
376 };
377 
378 
379 FASTJET_END_NAMESPACE // defined in fastjet/internal/base.hh
380 
381 #endif // __SISCONEBASEPLUGIN_HH__
382 
base class to store extra information that plugins may provide
deals with clustering
base class providing interface for a generic function of a PseudoJet
Contains any information related to the clustering that should be directly accessible to PseudoJet.
Class to contain pseudojets, including minimal information of use to jet-clustering routines.
Definition: PseudoJet.hh:68
int cluster_hist_index() const
return the cluster_hist_index, intended to be used by clustering routines.
Definition: PseudoJet.hh:830
Class that provides extra information about a SISCone clustering.
int pass(const PseudoJet &jet) const
return the # of the pass at which a given jet was found; will return -1 if the pass is invalid
const std::vector< PseudoJet > & protocones() const
an old name for getting the vector of stable cones (aka protocones)
double most_ambiguous_split() const
return the smallest difference in squared distance encountered during splitting between a particle an...
std::string description() const
return a brief summary of the contents of the extras object (specifically, the number of protocones.
const std::vector< PseudoJet > & stable_cones() const
returns a reference to the vector of stable cones (aka protocones)
SISConeBaseExtras(int nparticles)
constructor
template class derived from UserScaleBase::StryctureType that works for both SISCone jet classes impl...
virtual double ordering_var2() const
returns the sm_var2 (signed ordering variable squared) for this stable cone
virtual int constituent_index(unsigned int i) const
returns the index (in the original particle list) of the ith constituent
const Tjet & _jet
a reference to the internal jet in SISCone
virtual unsigned int size() const
returns the number of constituents
the structure that allows to store the information contained into a siscone::Cjet (built internally i...
virtual bool has_constituents() const
this structure has constituents
virtual std::vector< PseudoJet > constituents(const PseudoJet &) const
retrieve the constituents
const PseudoJet & constituent(unsigned int i) const
returns the ith constituent (as a PseusoJet)
virtual unsigned int size() const =0
returns the number of constituents
virtual std::string description() const
the textual descripotion
virtual int constituent_index(unsigned int i) const =0
returns the index (in the original particle list) of the ith constituent
StructureType(const ClusterSequence &cs)
base ctor (constructed from a ClusterSequence tin order to have access to the initial particles
virtual double ordering_var2() const =0
returns the sm_var2 (signed ordering variable squared) for this stable cone
const ClusterSequence & _cs
a reference to the CS (for access to the particles)
base class for user-defined ordering of stable cones (used for prorgessive removal)
virtual double result(const PseudoJet &jet) const =0
returns the scale associated with a given jet
virtual ~UserScaleBase()
empty virtual dtor