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RectangularGrid.hh
1 #ifndef __FASTJET_RECTANGULARGRID_HH__
2 #define __FASTJET_RECTANGULARGRID_HH__
3 
4 //FJSTARTHEADER
5 // $Id: RectangularGrid.hh 3771 2014-12-22 21:13:22Z salam $
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33 
34 #include "fastjet/PseudoJet.hh"
35 #include "fastjet/Selector.hh"
36 
37 FASTJET_BEGIN_NAMESPACE // defined in fastjet/internal/base.hh
38 
39 
40 //----------------------------------------------------------------------
41 /// Class to indicate generic structure of tilings
42 class TilingBase {
43 public:
44  /// returns the index of the tile in which p is located, or -1 if p
45  /// is outside the tiling region
46  virtual int tile_index(const PseudoJet & p) const = 0;
47 
48  /// returns the total number of tiles in the tiling; valid tile
49  /// indices run from 0 ... n_tiles()-1;
50  virtual int n_tiles() const = 0;
51 
52  /// returns the number of tiles that are "good"; i.e. there is scope
53  /// for having tiles that, for whatever reason, should be ignored;
54  /// there are situations in which having "non-good" tiles may be the
55  /// simplest mechanism to obtain a tiling with holes in it
56  virtual int n_good_tiles() const {return n_tiles();}
57 
58  /// returns whether a given tile is good
59  virtual bool tile_is_good(int /* itile */) const {return true;}
60 
61  /// returns whether all tiles are good
62  virtual bool all_tiles_good() const {return n_good_tiles() == n_tiles();}
63 
64  /// returns true if all tiles have the same area
65  virtual bool all_tiles_equal_area() const {return true;}
66 
67  /// returns the area of tile itile. Here with a default
68  /// implementation to return mean_tile_area(), consistent with the
69  /// fact that all_tiles_equal_area() returns true.
70  virtual double tile_area(int /* itile */) const {return mean_tile_area();}
71 
72  /// returns the mean area of the tiles.
73  virtual double mean_tile_area() const = 0;
74 
75  /// returns a string to describe the tiling
76  virtual std::string description() const = 0;
77 
78  /// returns true if the Tiling structure is in a suitably initialised state
79  virtual bool is_initialised() const = 0;
80  bool is_initialized() const {return is_initialised();}
81 
82  /// virtual destructor
83  virtual ~TilingBase() {}
84 };
85 
86 //----------------------------------------------------------------------
87 /// Class that holds a generic rectangular tiling
88 class RectangularGrid : public TilingBase {
89 public:
90  /// ctor with simple initialisation
91  /// \param rapmax the maximal absolute rapidity extent of the grid
92  /// \param cell_size the grid spacing (equivalently, cell size)
93  RectangularGrid(double rapmax_in, double cell_size) :
94  _ymax(rapmax_in), _ymin(-rapmax_in),
95  _requested_drap(cell_size), _requested_dphi(cell_size) {
96  _setup_grid();
97  }
98 
99  /// ctor with more control over initialisation
100  /// \param rapmin the minimum rapidity extent of the grid
101  /// \param rapmax the maximum rapidity extent of the grid
102  /// \param drap the grid spacing in rapidity
103  /// \param dphi the grid spacing in azimuth
104  /// \param tile_selector optional (geometric) selector to specify
105  /// which tiles are good; a tile is good if
106  /// a massless 4-vector at the center of the tile passes
107  /// the selection
108  RectangularGrid(double rapmin_in, double rapmax_in, double drap_in, double dphi_in,
109  Selector tile_selector = Selector())
110  : _ymax(rapmax_in), _ymin(rapmin_in),
111  _requested_drap(drap_in), _requested_dphi(dphi_in),
112  _tile_selector(tile_selector)
113  {
114  _setup_grid();
115  }
116 
117  /// dummy ctor (will give an unusable grid)
118  RectangularGrid();
119 
120  virtual int n_tiles() const {return _ntotal;}
121 
122  virtual int n_good_tiles() const {return _ngood;}
123 
124  // this was being kept inline, but it seems to make little
125  // difference whether it is or not (at least on Gavin's mac)
126  virtual int tile_index(const PseudoJet & p) const;
127 
128  /// returns whether a given tile is good
129  // tested in "issue" 2014-08-08-testing-rect-grid
130  virtual bool tile_is_good(int itile) const {return _tile_selector.worker() ? _is_good[itile] : true;}
131 
132  /// returns the area of tile itile.
133  virtual double tile_area(int /* itile */) const {return mean_tile_area();}
134 
135  /// returns the mean area of tiles.
136  virtual double mean_tile_area() const {return _dphi*_dy;};
137 
138  /// returns a textual description of the grid
139  virtual std::string description() const;
140 
141  /// returns the minimum rapidity extent of the grid
142  double rapmin() const {return _ymin;}
143  /// returns the maxmium rapidity extent of the grid
144  double rapmax() const {return _ymax;}
145  /// returns the spacing of the grid in rapidity
146  double drap() const {return _dy;}
147  /// returns the spacing of the grid in azimuth
148  double dphi() const {return _dphi;}
149 
150  /// returns true if the grid is in a suitably initialised state
151  virtual bool is_initialised() const {return _ntotal > 0;}
152 
153 private:
154  void _setup_grid();
155 
156  // information about the requested grid
157  double _ymax, _ymin; ///< maximal and minimal rapidity coverage of the grid
158  double _requested_drap; ///< requested rapidity spacing
159  double _requested_dphi; ///< requested phi spacing
160 
161  // information about the actual grid
162  double _dy, _dphi, _cell_area, _inverse_dy, _inverse_dphi;
163  int _ny, _nphi, _ntotal;
164  int _ngood;
165 
166  // a tile selector
167  Selector _tile_selector;
168  // if there's a tile selector, then for each tile, this caches the
169  // information about whether it is "good" i.e. it passes the tile
170  // selector
171  std::vector<bool> _is_good;
172 
173 };
174 
175 FASTJET_END_NAMESPACE // defined in fastjet/internal/base.hh
176 
177 #endif // __FASTJET_RECTANGULARGRID_HH__
virtual bool all_tiles_equal_area() const
returns true if all tiles have the same area
double drap() const
returns the spacing of the grid in rapidity
Class to indicate generic structure of tilings.
virtual int n_good_tiles() const
returns the number of tiles that are "good"; i.e.
virtual double tile_area(int) const
returns the area of tile itile.
virtual bool is_initialised() const
returns true if the grid is in a suitably initialised state
double rapmin() const
returns the minimum rapidity extent of the grid
RectangularGrid(double rapmax_in, double cell_size)
ctor with simple initialisation
double rapmax() const
returns the maxmium rapidity extent of the grid
virtual double mean_tile_area() const
returns the mean area of tiles.
Class that holds a generic rectangular tiling.
virtual bool tile_is_good(int) const
returns whether a given tile is good
virtual double tile_area(int) const
returns the area of tile itile.
virtual int n_good_tiles() const
returns the number of tiles that are "good"; i.e.
virtual int n_tiles() const
returns the total number of tiles in the tiling; valid tile indices run from 0 ...
virtual bool tile_is_good(int itile) const
returns whether a given tile is good
Class that encodes information about cuts and other selection criteria that can be applied to PseudoJ...
Definition: Selector.hh:149
virtual ~TilingBase()
virtual destructor
Class to contain pseudojets, including minimal information of use to jet-clustering routines...
Definition: PseudoJet.hh:67
virtual bool all_tiles_good() const
returns whether all tiles are good
double dphi() const
returns the spacing of the grid in azimuth
RectangularGrid(double rapmin_in, double rapmax_in, double drap_in, double dphi_in, Selector tile_selector=Selector())
ctor with more control over initialisation