FastJet 3.0.2
DnnPlane.hh
00001 //STARTHEADER
00002 // $Id: DnnPlane.hh 2577 2011-09-13 15:11:38Z salam $
00003 //
00004 // Copyright (c) 2005-2011, Matteo Cacciari, Gavin P. Salam and Gregory Soyez
00005 //
00006 //----------------------------------------------------------------------
00007 // This file is part of FastJet.
00008 //
00009 //  FastJet is free software; you can redistribute it and/or modify
00010 //  it under the terms of the GNU General Public License as published by
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00018 //
00019 //  FastJet is distributed in the hope that it will be useful,
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00023 //
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00026 //----------------------------------------------------------------------
00027 //ENDHEADER
00028 
00029 
00030 #ifndef DROP_CGAL // in case we do not have the code for CGAL
00031 
00032 #ifndef __FASTJET_DNNPLANE_HH__
00033 #define __FASTJET_DNNPLANE_HH__
00034 
00035 #include "fastjet/internal/Triangulation.hh"
00036 #include "fastjet/internal/DynamicNearestNeighbours.hh"
00037 
00038 FASTJET_BEGIN_NAMESPACE      // defined in fastjet/internal/base.hh
00039 
00040 
00041 /// \if internal_doc
00042 /// @ingroup internal
00043 /// \class DnnPlane
00044 /// class derived from DynamicNearestNeighbours that provides an
00045 /// implementation for the Euclidean plane
00046 /// \endif
00047 class DnnPlane : public DynamicNearestNeighbours {
00048  public:
00049   /// empty initaliser
00050   DnnPlane() {}
00051 
00052   /// Initialiser from a set of points on an Eta-Phi plane, where both
00053   /// eta and phi can have arbitrary ranges
00054   DnnPlane(const std::vector<EtaPhi> &, const bool & verbose = false );
00055 
00056 
00057   /// Returns the index of  the nearest neighbour of point labelled
00058   /// by ii (assumes ii is valid)
00059   int NearestNeighbourIndex(const int & ii) const ;
00060 
00061   /// Returns the distance to the nearest neighbour of point labelled
00062   /// by index ii (assumes ii is valid)
00063   double NearestNeighbourDistance(const int & ii) const ;
00064 
00065   /// Returns true iff the given index corresponds to a point that
00066   /// exists in the DNN structure (meaning that it has been added, and
00067   /// not removed in the meantime)
00068   bool Valid(const int & index) const;
00069 
00070   void RemoveAndAddPoints(const std::vector<int> & indices_to_remove,
00071                           const std::vector<EtaPhi> & points_to_add,
00072                           std::vector<int> & indices_added,
00073                           std::vector<int> & indices_of_updated_neighbours);
00074 
00075   /// returns the EtaPhi of point with index i.
00076   EtaPhi etaphi(const int i) const;
00077   /// returns the eta point with index i.
00078   double eta(const int i) const;
00079   /// returns the phi point with index i.
00080   double phi(const int i) const;
00081 
00082  private:
00083 
00084   /// Structure containing a vertex_handle and cached information on
00085   /// the nearest neighbour.
00086   struct SuperVertex {
00087     Vertex_handle vertex; // NULL indicates inexistence...
00088     double NNdistance;
00089     int NNindex;
00090     // later on for cylinder put a second vertex?
00091   };
00092 
00093   std::vector<SuperVertex> _supervertex;
00094   //set<Vertex_handle> _vertex_set;
00095   bool _verbose;
00096 
00097   static const bool _crash_on_coincidence = true;
00098   //static const bool _crash_on_coincidence = false;
00099 
00100   Triangulation _TR; /// CGAL object for dealing with triangulations
00101 
00102   /// calculates and returns the euclidean distance between points p1
00103   /// and p2
00104   inline double _euclid_distance(const Point& p1, const Point& p2) const {
00105     double distx= p1.x()-p2.x();
00106     double disty= p1.y()-p2.y();
00107     return distx*distx+disty*disty;
00108   }
00109 
00110   //---------------------------------------------------------------------- 
00111   /// Determines the index and distance of the nearest neighbour to 
00112   /// point j and puts the information into the _supervertex entry for j
00113   void _SetNearest(const int & j);
00114 
00115   //----------------------------------------------------------------------
00116   /// Determines and stores the nearest neighbour of j.
00117   ///
00118   /// For each voronoi neighbour D of j if the distance between j and D
00119   /// is less than D's own nearest neighbour, then update the
00120   /// nearest-neighbour info in D; push D's index onto 
00121   /// indices_of_updated_neighbours
00122   ///
00123   /// Note that j is NOT pushed onto indices_of_updated_neighbours --
00124   /// if you want it there, put it there yourself.
00125   void _SetAndUpdateNearest(const int & j, 
00126                             std::vector<int> & indices_of_updated_neighbours);
00127 
00128   /// given a vertex_handle returned by CGAL on insertion of a new
00129   /// points, crash if it turns out that it corresponds to a vertex
00130   /// that we already knew about (usually because two points coincide)
00131   void _CrashIfVertexPresent(const Vertex_handle & vertex, 
00132                              const int & its_index);
00133 
00134 };
00135 
00136 
00137 // here follow some inline implementations of the simpler of the
00138 // functions defined above
00139 
00140 inline int DnnPlane::NearestNeighbourIndex(const int & ii) const {
00141   return _supervertex[ii].NNindex;}
00142 
00143 inline double DnnPlane::NearestNeighbourDistance(const int & ii) const {
00144   return _supervertex[ii].NNdistance;}
00145 
00146 inline bool DnnPlane::Valid(const int & index) const {
00147   if (index >= 0 && index < static_cast<int>(_supervertex.size())) {
00148     return (_supervertex[index].vertex != NULL);} else {return false;} }
00149 
00150 inline EtaPhi DnnPlane::etaphi(const int i) const {
00151   Point * p = & (_supervertex[i].vertex->point());
00152   return EtaPhi(p->x(),p->y()); }
00153 
00154 inline double DnnPlane::eta(const int i) const {
00155   return _supervertex[i].vertex->point().x(); }
00156 
00157 inline double DnnPlane::phi(const int i) const {
00158   return _supervertex[i].vertex->point().y(); }
00159 
00160 
00161 FASTJET_END_NAMESPACE
00162 
00163 #endif //  __FASTJET_DNNPLANE_HH__
00164 
00165 #endif // DROP_CGAL
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