Dnn2piCylinder.hh

//STARTHEADER
// $Id: Dnn2piCylinder.hh 1816 2010-11-19 11:35:52Z salam $
//
// Copyright (c) 2005-2006, Matteo Cacciari and Gavin Salam
//
//----------------------------------------------------------------------
// This file is part of FastJet.
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#ifndef DROP_CGAL // in case we do not have the code for CGAL
#ifndef __FASTJET_DNN2PICYLINDER_HH__
#define __FASTJET_DNN2PICYLINDER_HH__

#include "fastjet/internal/DynamicNearestNeighbours.hh"
#include "fastjet/internal/DnnPlane.hh"
#include "fastjet/internal/numconsts.hh"

FASTJET_BEGIN_NAMESPACE      // defined in fastjet/internal/base.hh


class Dnn2piCylinder : public DynamicNearestNeighbours {
 public:
  Dnn2piCylinder() {}

  Dnn2piCylinder(const std::vector<EtaPhi> &,
                 const bool & ignore_nearest_is_mirror = false,
                 const bool & verbose = false );

  int NearestNeighbourIndex(const int & ii) const ;

  double NearestNeighbourDistance(const int & ii) const ;

  bool Valid(const int & index) const;

  void RemoveAndAddPoints(const std::vector<int> & indices_to_remove,
                          const std::vector<EtaPhi> & points_to_add,
                          std::vector<int> & indices_added,
                          std::vector<int> & indices_of_updated_neighbours);

  ~Dnn2piCylinder();

 private:

  // our extras to help us navigate, find distance, etc.
  const static int INEXISTENT_VERTEX=-3;

  bool _verbose;

  bool _ignore_nearest_is_mirror;


  struct MirrorVertexInfo {
    int main_index; 
    int mirror_index; 
  };

  // for each "true" vertex we have reference to indices in the euclidean
  // plane structure
  std::vector<MirrorVertexInfo> _mirror_info;
  // for each index in the euclidean 0--2pi plane structure we want to
  // be able to get back to the "true" vertex index on the overall
  // 0--2pi cylinder structure
  std::vector<int> _cylinder_index_of_plane_vertex;

  // NB: we define POINTERS here because the initialisation gave
  //     us problems (things crashed!), perhaps because in practice
  //     we were making a copy without being careful and defining
  //     a proper copy constructor.
  DnnPlane * _DNN;

  inline EtaPhi _remap_phi(const EtaPhi & point) {
    double phi = point.second;
    if (phi < pi) { phi += twopi ;} else {phi -= twopi;}
    return EtaPhi(point.first, phi);}


  //----------------------------------------------------------------------
  void _RegisterCylinderPoint (const EtaPhi & cylinder_point,
                               std::vector<EtaPhi> & plane_points);

  void _CreateNecessaryMirrorPoints(
                          const std::vector<int> & plane_indices,
                          std::vector<int> & updated_plane_points);

};


// here follow some inline implementations of the simpler of the
// functions defined above

//----------------------------------------------------------------------
inline int Dnn2piCylinder::NearestNeighbourIndex(const int & current) const {
  int main_index = _mirror_info[current].main_index;
  int mirror_index = _mirror_info[current].mirror_index;
  int plane_index;
  if (mirror_index == INEXISTENT_VERTEX ) {
    plane_index = _DNN->NearestNeighbourIndex(main_index);
  } else {
    plane_index = (
        _DNN->NearestNeighbourDistance(main_index) < 
        _DNN->NearestNeighbourDistance(mirror_index)) ? 
      _DNN->NearestNeighbourIndex(main_index) : 
      _DNN->NearestNeighbourIndex(mirror_index) ; 
  }
  int this_cylinder_index = _cylinder_index_of_plane_vertex[plane_index];
  // either the user has acknowledged the fact that they may get the
  // mirror copy as the closest point, or crash if it should occur
  // that mirror copy is the closest point.
  assert(_ignore_nearest_is_mirror || this_cylinder_index != current);
  //if (this_cylinder_index == current) {
  //  cerr << "WARNING point "<<current<<
  //    " has its mirror copy as its own nearest neighbour"<<endl;
  //}
  return this_cylinder_index;
}

inline double Dnn2piCylinder::NearestNeighbourDistance(const int & current) const {
  int main_index = _mirror_info[current].main_index;
  int mirror_index = _mirror_info[current].mirror_index;
  if (mirror_index == INEXISTENT_VERTEX ) {
    return _DNN->NearestNeighbourDistance(main_index);
  } else {
    return (
        _DNN->NearestNeighbourDistance(main_index) < 
        _DNN->NearestNeighbourDistance(mirror_index)) ? 
      _DNN->NearestNeighbourDistance(main_index) : 
      _DNN->NearestNeighbourDistance(mirror_index) ; 
  }
 
}

inline bool Dnn2piCylinder::Valid(const int & index) const {
  return (_DNN->Valid(_mirror_info[index].main_index));
}


inline Dnn2piCylinder::~Dnn2piCylinder() {
  delete _DNN; 
}


FASTJET_END_NAMESPACE

#endif //  __FASTJET_DNN2PICYLINDER_HH__
#endif //DROP_CGAL