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ClosestPair2DBase.hh
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30 
31 #ifndef __FASTJET_CLOSESTPAIR2DBASE__HH__
32 #define __FASTJET_CLOSESTPAIR2DBASE__HH__
33 
34 #include<vector>
35 #include "fastjet/internal/base.hh"
36 
37 FASTJET_BEGIN_NAMESPACE // defined in fastjet/internal/base.hh
38 
39 //----------------------------------------------------------------------
40 /// \if internal_doc
41 /// @ingroup internal
42 /// \class Coord2D
43 /// class for representing 2d coordinates and carrying out some basic
44 /// operations on them
45 /// \endif
46 class Coord2D {
47 public:
48  double x, y;
49 
50  Coord2D() {};
51 
52  Coord2D(double a, double b): x(a), y(b) {};
53 
54  /// return the vector difference between two coordinates
55  Coord2D operator-(const Coord2D & other) const {
56  return Coord2D(x - other.x, y - other.y);};
57 
58  /// return the vector sum between two coordinates
59  Coord2D operator+(const Coord2D & other) const {
60  return Coord2D(x + other.x, y + other.y);};
61 
62  /// return the product of the coordinate with the factor
63  Coord2D operator*(double factor) const {return Coord2D(factor*x,factor*y);};
64  friend Coord2D operator*(double factor, const Coord2D & coord) {
65  return Coord2D(factor*coord.x,factor*coord.y);
66  }
67 
68  /// division of each component of coordinate
69  Coord2D operator/(double divisor) const {
70  return Coord2D(x / divisor, y / divisor);};
71 
72  /// return the squared distance between two coordinates
73  friend double distance2(const Coord2D & a, const Coord2D & b) {
74  double dx = a.x - b.x, dy = a.y-b.y;
75  return dx*dx+dy*dy;
76  };
77  /// return the squared distance between two coordinates
78  double distance2(const Coord2D & b) const {
79  double dx = x - b.x, dy = y-b.y;
80  return dx*dx+dy*dy;
81  };
82 };
83 
84 
85 //----------------------------------------------------------------------
86 /// \if internal_doc
87 /// @ingroup internal
88 /// \class ClosestPair2DBase
89 /// abstract base class for finding closest pairs in 2D
90 /// \endif
91 class ClosestPair2DBase {
92 public:
93  /// provides the IDs of the closest pair as well as the squared
94  /// distance between them
95  virtual void closest_pair(unsigned int & ID1, unsigned int & ID2,
96  double & distance2) const = 0;
97 
98  /// removes the entry labelled by ID from the object;
99  virtual void remove(unsigned int ID) = 0;
100 
101  /// inserts the position into the closest pair structure and returns the
102  /// ID that has been allocated for the object.
103  virtual unsigned int insert(const Coord2D & position) = 0;
104 
105  /// replaces the specified ID1 and ID2 with something at a new position
106  /// assuming that ID1 and ID2 are in sequence wrt position; it returns
107  /// the ID of the new object...
108  virtual unsigned int replace(unsigned int ID1, unsigned int ID2,
109  const Coord2D & position) {
110  remove(ID1);
111  remove(ID2);
112  unsigned new_ID = insert(position);
113  return(new_ID);
114  };
115 
116  /// replaces IDs_to_remove with points at the new_positions
117  /// indicating the IDs allocated to the new points in new_IDs
118  virtual void replace_many(const std::vector<unsigned int> & IDs_to_remove,
119  const std::vector<Coord2D> & new_positions,
120  std::vector<unsigned int> & new_IDs) {
121  for(unsigned i = 0; i < IDs_to_remove.size(); i++) {
122  remove(IDs_to_remove[i]);}
123  new_IDs.resize(0);
124  for(unsigned i = 0; i < new_positions.size(); i++) {
125  new_IDs.push_back(insert(new_positions[i]));}
126  }
127 
128  virtual unsigned int size() = 0;
129 
130  virtual ~ClosestPair2DBase() {};
131 
132 };
133 
134 
135 FASTJET_END_NAMESPACE
136 
137 #endif // __FASTJET_CLOSESTPAIR2DBASE__HH__
Selector operator*(const Selector &s1, const Selector &s2)
successive application of 2 selectors
Definition: Selector.cc:559