DynamicNearestNeighbours.hh

//STARTHEADER
// $Id: DynamicNearestNeighbours.hh 1761 2010-09-16 10:43:18Z soyez $
//
// Copyright (c) 2005-2006, Matteo Cacciari and Gavin Salam
//
//----------------------------------------------------------------------
// This file is part of FastJet.
//
//  FastJet is free software; you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation; either version 2 of the License, or
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//  development and are described in hep-ph/0512210. If you use
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//  GNU General Public License for more details.
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//ENDHEADER


#ifndef __FASTJET_DYNAMICNEARESTNEIGHBOURS_HH__
#define __FASTJET_DYNAMICNEARESTNEIGHBOURS_HH__

#include<vector>
#include<string>
#include<iostream>
#include<sstream>
#include<cassert>
#include "fastjet/internal/numconsts.hh"

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

//typedef std::pair<double,double> EtaPhi;

class EtaPhi {
public:
  double first, second;
  EtaPhi() {}
  EtaPhi(double a, double b) {first = a; second = b;}
  void sanitize() {    
    if (second <  0)     second += twopi; 
    if (second >= twopi) second -= twopi;
  }

};

class DnnError {
public:
  // constructors
  DnnError() {;};
  DnnError(const std::string & message) {
    _message = message; std::cerr << message << std::endl;};

  std::string message() const {return _message;};

private:
  std::string _message;
};


class DynamicNearestNeighbours {

public:
  //virtual DynamicNearestNeighbours() {};
   
  //virtual DynamicNearestNeighbours(const std::vector<EtaPhi> &, 
  //                               const bool & verbose = false ) = 0;

  virtual int NearestNeighbourIndex(const int & ii) const = 0;

  virtual double NearestNeighbourDistance(const int & ii) const = 0;

  virtual bool Valid(const int & index) const = 0;

  virtual 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) = 0;


  inline void RemovePoint (const int & index,
                           std::vector<int> & indices_of_updated_neighbours) {
    std::vector<int> indices_added;
    std::vector<EtaPhi> points_to_add;
    std::vector<int> indices_to_remove(1);
    indices_to_remove[0] = index;
    RemoveAndAddPoints(indices_to_remove, points_to_add, indices_added,
                       indices_of_updated_neighbours
                       );};


  inline void RemoveCombinedAddCombination(
                        const int & index1, const int & index2,
                        const EtaPhi & newpoint,
                        int & index3,
                        std::vector<int> & indices_of_updated_neighbours) {
    std::vector<int> indices_added(1);
    std::vector<EtaPhi> points_to_add(1);
    std::vector<int> indices_to_remove(2);
    indices_to_remove[0] = index1;
    indices_to_remove[1] = index2;
    points_to_add[0] = newpoint;
    RemoveAndAddPoints(indices_to_remove, points_to_add, indices_added,
                       indices_of_updated_neighbours
                       );
    index3 = indices_added[0];
  };

  virtual ~DynamicNearestNeighbours () {}
};
  

FASTJET_END_NAMESPACE

#endif // __FASTJET_DYNAMICNEARESTNEIGHBOURS_HH__