FastJet  3.1.0-beta.1
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Friends Groups Pages
GhostedAreaSpec.hh
1 //FJSTARTHEADER
2 // $Id: GhostedAreaSpec.hh 3433 2014-07-23 08:17:03Z salam $
3 //
4 // Copyright (c) 2005-2014, Matteo Cacciari, Gavin P. Salam and Gregory Soyez
5 //
6 //----------------------------------------------------------------------
7 // This file is part of FastJet.
8 //
9 // FastJet is free software; you can redistribute it and/or modify
10 // it under the terms of the GNU General Public License as published by
11 // the Free Software Foundation; either version 2 of the License, or
12 // (at your option) any later version.
13 //
14 // The algorithms that underlie FastJet have required considerable
15 // development. They are described in the original FastJet paper,
16 // hep-ph/0512210 and in the manual, arXiv:1111.6097. If you use
17 // FastJet as part of work towards a scientific publication, please
18 // quote the version you use and include a citation to the manual and
19 // optionally also to hep-ph/0512210.
20 //
21 // FastJet is distributed in the hope that it will be useful,
22 // but WITHOUT ANY WARRANTY; without even the implied warranty of
23 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
24 // GNU General Public License for more details.
25 //
26 // You should have received a copy of the GNU General Public License
27 // along with FastJet. If not, see <http://www.gnu.org/licenses/>.
28 //----------------------------------------------------------------------
29 //FJENDHEADER
30 
31 
32 #ifndef __FASTJET_GHOSTEDAREASPEC_HH__
33 #define __FASTJET_GHOSTEDAREASPEC_HH__
34 
35 #include<vector>
36 #include<string>
37 #include "fastjet/PseudoJet.hh"
38 #include "fastjet/internal/BasicRandom.hh"
39 #include "fastjet/Selector.hh"
40 #include "fastjet/LimitedWarning.hh"
41 
42 //
43 #define STATIC_GENERATOR 1
44 
45 FASTJET_BEGIN_NAMESPACE // defined in fastjet/internal/base.hh
46 
47 /// namespace to hold default parameters for the active area spec
48 namespace gas {
49  const double def_ghost_maxrap = 6.0;
50  const int def_repeat = 1;
51  const double def_ghost_area = 0.01;
52  const double def_grid_scatter = 1.0;
53  const double def_pt_scatter = 0.1;
54  const double def_mean_ghost_pt = 1e-100;
55 }
56 
57 //----------------------------------------------------------------------
58 /// @ingroup area_classes
59 /// \class GhostedAreaSpec
60 /// Parameters to configure the computation of jet areas using ghosts
61 ///
62 /// Class that defines the parameters that go into the measurement
63 /// of active jet areas.
64 class GhostedAreaSpec {
65 public:
66  /// default constructor
67  GhostedAreaSpec(): _ghost_maxrap (gas::def_ghost_maxrap),
68  _ghost_rap_offset(0.0),
69  _repeat (gas::def_repeat),
70  _ghost_area (gas::def_ghost_area),
71  _grid_scatter (gas::def_grid_scatter),
72  _pt_scatter (gas::def_pt_scatter),
73  _mean_ghost_pt(gas::def_mean_ghost_pt),
74  _fj2_placement(false) {_initialize();}
75 
76  /// explicit constructor
77  explicit GhostedAreaSpec(double ghost_maxrap_in,
78  int repeat_in = gas::def_repeat,
79  double ghost_area_in = gas::def_ghost_area,
80  double grid_scatter_in = gas::def_grid_scatter,
81  double pt_scatter_in = gas::def_pt_scatter,
82  double mean_ghost_pt_in = gas::def_mean_ghost_pt
83  ):
84  _ghost_maxrap(ghost_maxrap_in),
85  _ghost_rap_offset(0.0),
86  _repeat(repeat_in),
87  _ghost_area(ghost_area_in),
88  _grid_scatter(grid_scatter_in),
89  _pt_scatter(pt_scatter_in),
90  _mean_ghost_pt(mean_ghost_pt_in),
91  _fj2_placement(false) {_initialize();}
92 
93  /// explicit constructor
94  explicit GhostedAreaSpec(double ghost_minrap_in,
95  double ghost_maxrap_in,
96  int repeat_in = gas::def_repeat,
97  double ghost_area_in = gas::def_ghost_area,
98  double grid_scatter_in = gas::def_grid_scatter,
99  double pt_scatter_in = gas::def_pt_scatter,
100  double mean_ghost_pt_in = gas::def_mean_ghost_pt
101  ):
102  _ghost_maxrap (0.5*(ghost_maxrap_in - ghost_minrap_in)),
103  _ghost_rap_offset(0.5*(ghost_maxrap_in + ghost_minrap_in)),
104  _repeat(repeat_in),
105  _ghost_area(ghost_area_in),
106  _grid_scatter(grid_scatter_in),
107  _pt_scatter(pt_scatter_in),
108  _mean_ghost_pt(mean_ghost_pt_in),
109  _fj2_placement(false) {_initialize();}
110 
111 
112  /// constructor based on a Selector
113  explicit GhostedAreaSpec(const Selector & selector,
114  int repeat_in = gas::def_repeat,
115  double ghost_area_in = gas::def_ghost_area,
116  double grid_scatter_in = gas::def_grid_scatter,
117  double pt_scatter_in = gas::def_pt_scatter,
118  double mean_ghost_pt_in = gas::def_mean_ghost_pt
119  );
120 
121 
122  /// does the initialization of actual ghost parameters
123  void _initialize();
124 
125  // for accessing values set by the user
126  inline double ghost_rapmax () const {return _ghost_maxrap;}
127  inline double ghost_maxrap () const {return _ghost_maxrap;}
128  inline double ghost_etamax () const {return _ghost_maxrap;}
129  inline double ghost_maxeta () const {return _ghost_maxrap;}
130  inline double ghost_area () const {return _ghost_area ;}
131  inline double grid_scatter () const {return _grid_scatter;}
132  inline double pt_scatter () const {return _pt_scatter ;}
133  inline double mean_ghost_pt() const {return _mean_ghost_pt ;}
134  inline int repeat () const {return _repeat ;}
135  inline bool fj2_placement() const {return _fj2_placement;}
136 
137  inline double kt_scatter () const {return _pt_scatter ;}
138  inline double mean_ghost_kt() const {return _mean_ghost_pt ;}
139 
140  // for accessing values
141  inline double actual_ghost_area() const {return _actual_ghost_area;}
142  inline int n_ghosts() const {return _n_ghosts;}
143 
144  // when explicitly modifying values, sometimes call the initializer
145  inline void set_ghost_area (double val) {_ghost_area = val; _initialize();}
146  inline void set_ghost_rapmax (double val) {_ghost_maxrap = val; _initialize();}
147  inline void set_ghost_maxrap (double val) {_ghost_maxrap = val; _initialize();}
148  inline void set_ghost_etamax (double val) {_ghost_maxrap = val; _initialize();}
149  inline void set_ghost_maxeta (double val) {_ghost_maxrap = val; _initialize();}
150  inline void set_grid_scatter (double val) {_grid_scatter = val; }
151  inline void set_pt_scatter (double val) {_pt_scatter = val; }
152  inline void set_mean_ghost_pt(double val) {_mean_ghost_pt = val; }
153  inline void set_repeat (int val) {_repeat = val; }
154 
155  inline void set_kt_scatter (double val) {_pt_scatter = val; }
156  inline void set_mean_ghost_kt(double val) {_mean_ghost_pt = val; }
157 
158  /// if val is true, set ghost placement as it was in FastJet 2.X. The
159  /// main differences between FJ2 and FJ3 ghost placement are
160  ///
161  /// - in FJ2 the rapidity spacing was
162  /// ceil((maxrap-minrap)/sqrt(area)), while in FJ3 it is
163  /// int((maxrap-minrap)/sqrt(area) + 0.5) [similarly for phi].
164  /// The FJ3 option offers more stability when trying to specify a
165  /// spacing that exactly fits the extent.
166  ///
167  /// - in FJ2, the ghosts are placed at the corners of grid cells
168  /// (i.e. extending up to maxrap), while in FJ3 they are placed at
169  /// the centres of grid cells (i.e. extending roughly up to
170  /// maxrap-sqrt(area)). The FJ2 behaviour effectively skews the
171  /// total area coverage when maxrap is small, by an amount
172  /// sqrt(area)/(2*maxrap).
173  ///
174  /// FJ2 placement is now deprecated.
175  void set_fj2_placement(bool val);
176 
177  /// return nphi (ghosts layed out (-nrap, 0..nphi-1), (-nrap+1,0..nphi-1),
178  /// ... (nrap,0..nphi-1)
179  inline int nphi() const {return _nphi;}
180  inline int nrap() const {return _nrap;}
181 
182  /// get all relevant information about the status of the
183  /// random number generator, so that it can be reset subsequently
184  /// with set_random_status.
185  inline void get_random_status(std::vector<int> & __iseed) const {
186  _random_generator.get_status(__iseed);}
187 
188  /// set the status of the random number generator, as obtained
189  /// previously with get_random_status. Note that the random
190  /// generator is a static member of the class, i.e. common to all
191  /// instances of the class --- so if you modify the random for this
192  /// instance, you modify it for all instances.
193  inline void set_random_status(const std::vector<int> & __iseed) {
194  _random_generator.set_status(__iseed);}
195 
196  inline void checkpoint_random() {get_random_status(_random_checkpoint);}
197  inline void restore_checkpoint_random() {set_random_status(_random_checkpoint);}
198 
199  /// for a summary
200  std::string description() const;
201 
202  /// push a set of ghost 4-momenta onto the back of the vector of
203  /// PseudoJets
204  void add_ghosts(std::vector<PseudoJet> & ) const;
205 
206  /// very deprecated public access to a random number
207  /// from the internal generator
208  inline double random_at_own_risk() const {return _our_rand();}
209  /// very deprecated public access to the generator itself
210  inline BasicRandom<double> & generator_at_own_risk() const {
211  return _random_generator;}
212 
213 private:
214 
215  // quantities that determine nature and distribution of ghosts
216  double _ghost_maxrap;
217  double _ghost_rap_offset;
218  int _repeat ;
219  double _ghost_area ;
220  double _grid_scatter;
221  double _pt_scatter ;
222  double _mean_ghost_pt;
223  bool _fj2_placement;
224 
225  Selector _selector;
226 
227  // derived quantities
228  double _actual_ghost_area, _dphi, _drap;
229  int _n_ghosts, _nphi, _nrap;
230 
231 
232  std::vector<int> _random_checkpoint;
233  static BasicRandom<double> _random_generator;
234  //mutable BasicRandom<double> _random_generator;
235 
236  static LimitedWarning _warn_fj2_placement_deprecated;
237 
238  inline double _our_rand() const {return _random_generator();}
239 
240 };
241 
242 /// just provide a typedef for backwards compatibility with programs
243 /// based on versions 2.0 and 2.1 of fastjet. Since there is no
244 /// easy way of telling people this is deprecated at compile or run
245 /// time, we should be careful before removing this in the future.
246 typedef GhostedAreaSpec ActiveAreaSpec;
247 
248 
249 FASTJET_END_NAMESPACE
250 
251 #endif // __FASTJET_GHOSTEDAREASPEC_HH__
Generated on Fri Aug 15 2014 16:12:48 for FastJet by   doxygen 1.8.4