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CompositeJetStructure.hh
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2 // $Id: CompositeJetStructure.hh 2684 2011-11-14 07:41:44Z soyez $
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28 
29 
30 #ifndef __FASTJET_COMPOSITEJET_STRUCTURE_HH__
31 #define __FASTJET_COMPOSITEJET_STRUCTURE_HH__
32 
33 #include <fastjet/PseudoJet.hh>
34 #include <fastjet/PseudoJetStructureBase.hh>
35 
36 // to have access to the recombiner we need to include the JetDefinition header
37 #include <fastjet/JetDefinition.hh>
38 
39 FASTJET_BEGIN_NAMESPACE // defined in fastjet/internal/base.hh
40 
41 /// @ingroup extra_info
42 /// \class CompositeJetStructure
43 /// The structure for a jet made of pieces
44 ///
45 /// This stores the vector of the pieces that make the jet and provide
46 /// the methods to access them
48 public:
49  // basic class info
50  //-------------------------------------------------------------------
51  /// default ctor
52  CompositeJetStructure() : _area_4vector_ptr(0){};
53 
54  /// ctor with initialisation
55  CompositeJetStructure(const std::vector<PseudoJet> & initial_pieces,
56  const JetDefinition::Recombiner * recombiner = 0);
57 
58  /// default dtor
60  if (_area_4vector_ptr) delete _area_4vector_ptr;
61  };
62 
63  /// description
64  virtual std::string description() const;
65 
66  // things reimplemented from the base structure
67  //-------------------------------------------------------------------
68  /// true unless the jet has no pieces (see also the description of
69  /// constituents() below)
70  virtual bool has_constituents() const;
71 
72  /// return the constituents (i.e. the union of the constituents of each piece)
73  ///
74  /// If any of the pieces has no constituent, the piece itself is
75  /// considered as a constituent
76  /// Note that as a consequence, a composite jet with no pieces will
77  /// have an empty vector as constituents
78  virtual std::vector<PseudoJet> constituents(const PseudoJet &jet) const;
79 
80  //-------------------------------------------------------------------
81  // information related to the pieces of the jet
82  //-------------------------------------------------------------------
83  /// true if it has pieces (always the case)
84  virtual bool has_pieces(const PseudoJet & /*jet*/) const {return true;}
85 
86  /// returns the pieces
87  virtual std::vector<PseudoJet> pieces(const PseudoJet &jet) const;
88 
89  // area-related material
90 
91  /// check if it has a well-defined area
92  virtual bool has_area() const;
93 
94  /// return the jet (scalar) area.
95  virtual double area(const PseudoJet &reference) const;
96 
97  /// return the error (uncertainty) associated with the determination
98  /// of the area of this jet.
99  ///
100  /// Be conservative: return the sum of the errors
101  virtual double area_error(const PseudoJet &reference) const;
102 
103  /// return the jet 4-vector area.
104  virtual PseudoJet area_4vector(const PseudoJet &reference) const;
105 
106  /// true if this jet is made exclusively of ghosts.
107  ///
108  /// In this case, it will be true if all pieces are pure ghost
109  virtual bool is_pure_ghost(const PseudoJet &reference) const;
110 
111  // allow to modify the area information
112  // (for use in join())
113  //------------------------------------------------------------------------------
114  void set_area_information(PseudoJet *area_4vector_ptr){
115  _area_4vector_ptr = area_4vector_ptr;
116  }
117 
118 
119 protected:
120  std::vector<PseudoJet> _pieces; ///< the pieces building the jet
121  PseudoJet * _area_4vector_ptr; ///< pointer to the 4-vector jet area
122 };
123 
124 
125 
126 // helpers to "join" jets and produce a structure derived from
127 // CompositeJetStructure
128 //
129 // The template structure T must have a constructor accepting as
130 // argument the pieces and of the composite jet
131 // ------------------------------------------------------------------------
132 
133 /// build a "CompositeJet" from the vector of its pieces with an
134 /// extended structure of type T derived from CompositeJetStructure
135 template<typename T> PseudoJet join(const std::vector<PseudoJet> & pieces){
136  PseudoJet result(0.0,0.0,0.0,0.0);
137  for (unsigned int i=0; i<pieces.size(); i++){
138  const PseudoJet it = pieces[i];
139  result += it;
140  }
141 
142  T *cj_struct = new T(pieces);
144 
145  return result;
146 }
147 
148 
149 /// build a "CompositeJet" from a single PseudoJet with an extended
150 /// structure of type T derived from CompositeJetStructure
151 template<typename T> PseudoJet join(const PseudoJet & j1){
152  return join<T>(std::vector<PseudoJet>(1,j1));
153 }
154 
155 /// build a "CompositeJet" from two PseudoJet with an extended
156 /// structure of type T derived from CompositeJetStructure
157 template<typename T> PseudoJet join(const PseudoJet & j1, const PseudoJet & j2){
158  std::vector<PseudoJet> pieces;
159  pieces.push_back(j1);
160  pieces.push_back(j2);
161  return join<T>(pieces);
162 }
163 
164 /// build a "CompositeJet" from 3 PseudoJet with an extended structure
165 /// of type T derived from CompositeJetStructure
166 template<typename T> PseudoJet join(const PseudoJet & j1, const PseudoJet & j2,
167  const PseudoJet & j3){
168  std::vector<PseudoJet> pieces;
169  pieces.push_back(j1);
170  pieces.push_back(j2);
171  pieces.push_back(j3);
172  return join<T>(pieces);
173 }
174 
175 /// build a "CompositeJet" from 4 PseudoJet with an extended structure
176 /// of type T derived from CompositeJetStructure
177 template<typename T> PseudoJet join(const PseudoJet & j1, const PseudoJet & j2,
178  const PseudoJet & j3, const PseudoJet & j4){
179  std::vector<PseudoJet> pieces;
180  pieces.push_back(j1);
181  pieces.push_back(j2);
182  pieces.push_back(j3);
183  pieces.push_back(j4);
184  return join<T>(pieces);
185 }
186 
187 
188 // the same as above with an additional argument for a
189 // user-defined recombiner
190 //
191 // The template structure T must be derived from CompositeJetStructure
192 // and have a constructor accepting as arguments the pieces and a
193 // pointer to the recombination scheme
194 // ----------------------------------------------------------------------
195 
196 /// build a "CompositeJet" from the vector of its pieces with an
197 /// extended structure of type T derived from CompositeJetStructure
198 template<typename T> PseudoJet join(const std::vector<PseudoJet> & pieces,
199  const JetDefinition::Recombiner & recombiner){
200  PseudoJet result;
201  if (pieces.size()>0){
202  result = pieces[0];
203  for (unsigned int i=1; i<pieces.size(); i++){
204  recombiner.plus_equal(result, pieces[i]);
205  }
206  }
207 
208  T *cj_struct = new T(pieces, &recombiner);
210 
211  return result;
212 }
213 
214 /// build a "CompositeJet" from a single PseudoJet with an extended
215 /// structure of type T derived from CompositeJetStructure
216 template<typename T> PseudoJet join(const PseudoJet & j1,
217  const JetDefinition::Recombiner & recombiner){
218  return join<T>(std::vector<PseudoJet>(1,j1), recombiner);
219 }
220 
221 /// build a "CompositeJet" from two PseudoJet with an extended
222 /// structure of type T derived from CompositeJetStructure
223 template<typename T> PseudoJet join(const PseudoJet & j1, const PseudoJet & j2,
224  const JetDefinition::Recombiner & recombiner){
225  std::vector<PseudoJet> pieces;
226  pieces.push_back(j1);
227  pieces.push_back(j2);
228  return join<T>(pieces, recombiner);
229 }
230 
231 /// build a "CompositeJet" from 3 PseudoJet with an extended structure
232 /// of type T derived from CompositeJetStructure
233 template<typename T> PseudoJet join(const PseudoJet & j1, const PseudoJet & j2,
234  const PseudoJet & j3,
235  const JetDefinition::Recombiner & recombiner){
236  std::vector<PseudoJet> pieces;
237  pieces.push_back(j1);
238  pieces.push_back(j2);
239  pieces.push_back(j3);
240  return join<T>(pieces, recombiner);
241 }
242 
243 /// build a "CompositeJet" from 4 PseudoJet with an extended structure
244 /// of type T derived from CompositeJetStructure
245 template<typename T> PseudoJet join(const PseudoJet & j1, const PseudoJet & j2,
246  const PseudoJet & j3, const PseudoJet & j4,
247  const JetDefinition::Recombiner & recombiner){
248  std::vector<PseudoJet> pieces;
249  pieces.push_back(j1);
250  pieces.push_back(j2);
251  pieces.push_back(j3);
252  pieces.push_back(j4);
253  return join<T>(pieces, recombiner);
254 }
255 
256 
257 FASTJET_END_NAMESPACE // defined in fastjet/internal/base.hh
258 
259 #endif // __FASTJET_MERGEDJET_STRUCTURE_HH__