Voronoi.hh

#ifndef __FASTJET__VORONOI_H__
#define __FASTJET__VORONOI_H__

//FJSTARTHEADER
// $Id: Voronoi.hh 4420 2019-11-29 09:28:20Z soyez $
//
// Copyright (c) 2005-2019, Matteo Cacciari, Gavin P. Salam and Gregory Soyez
//
//----------------------------------------------------------------------
// 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
//  (at your option) any later version.
//
//  The algorithms that underlie FastJet have required considerable
//  development. They are described in the original FastJet paper,
//  hep-ph/0512210 and in the manual, arXiv:1111.6097. If you use
//  FastJet as part of work towards a scientific publication, please
//  quote the version you use and include a citation to the manual and
//  optionally also to hep-ph/0512210.
//
//  FastJet is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with FastJet. If not, see <http://www.gnu.org/licenses/>.
//----------------------------------------------------------------------
//FJENDHEADER


/*
* The author of this software is Steven Fortune.  
* Copyright (c) 1994 by AT&T Bell Laboratories.
* Permission to use, copy, modify, and distribute this software for any
* purpose without fee is hereby granted, provided that this entire notice
* is included in all copies of any software which is or includes a copy
* or modification of this software and in all copies of the supporting
* documentation for such software.
* THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTY.  IN PARTICULAR, NEITHER THE AUTHORS NOR AT&T MAKE ANY
* REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
* OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
*/

/* 
* This code was originally written by Stephan Fortune in C code.  I,
* Shane O'Sullivan, have since modified it, encapsulating it in a C++
* class and, fixing memory leaks and adding accessors to the Voronoi
* Edges.  Permission to use, copy, modify, and distribute this
* software for any purpose without fee is hereby granted, provided
* that this entire notice is included in all copies of any software
* which is or includes a copy or modification of this software and in
* all copies of the supporting documentation for such software.  THIS
* SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTY.  IN PARTICULAR, NEITHER THE AUTHORS NOR AT&T MAKE ANY
* REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
* MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
* PURPOSE.
*/

/*
 * This code, included in the FastJet distribution, was originally
 * written by Stephan Fortune in C and adapted to C++ by Shane
 * O'Sullivan under the terms repported above.
 *
 * Below are the list of changes implemented by the FastJet authors:
 *
 * 2011-11-14  Gregory Soyez  <soyez@fastjet.fr>
 * 
 *      * removed 'plot' and 'triangulate' (were always 0)
 *      * removed unused plot functions (openpl, circle, range, 
 *        out_bisector, out_ep, out_vertex, out_site, out_triple)
 *      * removed unused 'VPoint p' in 'intersect'
 * 
 * 
 * 2011-07-22  Gregory Soyez  <soyez@fastjet.fr>
 * 
 *      * replaced Point by VPoint (to avoid any potential conflict
 *        with an already existing class Point in FastJet
 * 
 * 
 * 2008-04-01  Gregory Soyez  <soyez@fastjet.fr>
 * 
 *      * declared ystar volatile in HalfEdge (apparently fixes a bug
 *        related to VD computations with points on a grid)
 * 
 * 
 * 2007-05-07  Gregory Soyez  <soyez@fastjet.fr>
 * 
 *      * put the code in the fastjet namespace
 * 
 *      * replaced float by double
 * 
 *      * generateVoronoi() takes a vector of Point instead of 2
 *        pointers
 * 
 *      * added info about the parent sites to GraphEdge
 * 
 *      * removed condition on minimal distance between sites
 * 
 */

#include "fastjet/LimitedWarning.hh"
#include <vector>
#include <math.h>
#include <stdlib.h>
#include <string.h>

#define DELETED -2
#define le 0
#define re 1

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

/**
 * \if internal_doc
 * @ingroup internal
 * \class VPoint
 * class to handle a 2d point
 * \endif
 */
class VPoint{
public:
  /// defailt ctor
  VPoint() : x(0.0), y(0.0) {}

  /// ctor with initialisation
  VPoint(double _x, double _y) : x(_x), y(_y) {}

  /// addition
  inline VPoint operator + (const VPoint &p) const{
    return VPoint(x+p.x, y+p.y);
  }

  /// subtraction
  inline VPoint operator - (const VPoint &p) const{
    return VPoint(x-p.x, y-p.y);
  }

  /// scalar multiplication
  inline VPoint operator * (const double t) const{
    return VPoint(x*t, y*t);
  }

  /// vector coordinates
  double x,y;
};


/// norm of a vector
inline double norm(const VPoint p){
  return p.x*p.x+p.y*p.y;
}


/// 2D vector product
inline double vector_product(const VPoint &p1, const VPoint &p2){
  return p1.x*p2.y-p1.y*p2.x;
}


/// scalar product
inline double scalar_product(const VPoint &p1, const VPoint &p2){
  return p1.x*p2.x+p1.y*p2.y;
}


/**
 * \if internal_doc
 * @ingroup internal
 * \class GraphEdge
 * handle an edge of the Voronoi Diagram.
 * \endif
 */
class GraphEdge{
public:
  /// coordinates of the extreme points
  double x1,y1,x2,y2;

  /// indices of the parent sites that define the edge
  int point1, point2;

  /// pointer to the next edge
  GraphEdge* next;
};


/**
 * \if internal_doc
 * @ingroup internal
 * \class Site
 * structure used both for particle sites and for vertices.
 * \endif
 */
class Site{
 public:
  VPoint        coord;
  int sitenbr;
  int refcnt;
};



class Freenode{
public:
  Freenode *nextfree;
};


class FreeNodeArrayList{
public:
  Freenode* memory;
  FreeNodeArrayList* next;
};


class Freelist{
public:
  Freenode *head;
  int nodesize;
};

class Edge{
public:
  double a,b,c;
  Site *ep[2];
  Site *reg[2];
  int edgenbr;
};


class Halfedge{
public:
  Halfedge *ELleft, *ELright;
  Edge *ELedge;
  int ELrefcnt;
  char ELpm;
  Site *vertex;
  volatile double ystar;
  Halfedge *PQnext;
};

/**
 * \if internal_doc
 * @ingroup internal
 * \class VoronoiDiagramGenerator
 * Shane O'Sullivan C++ version of Stephan Fortune Voronoi diagram
 * generator
 * \endif
 */
class VoronoiDiagramGenerator{
public:
  VoronoiDiagramGenerator();
  ~VoronoiDiagramGenerator();

  bool generateVoronoi(std::vector<VPoint> *_parent_sites,
                       double minX, double maxX, double minY, double maxY, 
                       double minDist=0);

  inline void resetIterator(){
    iteratorEdges = allEdges;
  }

  bool getNext(GraphEdge **e){
    if(iteratorEdges == 0)
      return false;
    
    *e = iteratorEdges;
    iteratorEdges = iteratorEdges->next;
    return true;
  }
  
  std::vector<VPoint> *parent_sites;
  int n_parent_sites;

private:
  void cleanup();
  void cleanupEdges();
  char *getfree(Freelist *fl);  
  Halfedge *PQfind();
  int PQempty();
        
  Halfedge **ELhash;
  Halfedge *HEcreate(), *ELleft(), *ELright(), *ELleftbnd();
  Halfedge *HEcreate(Edge *e,int pm);
  
  VPoint PQ_min();
  Halfedge *PQextractmin();     
  void freeinit(Freelist *fl,int size);
  void makefree(Freenode *curr,Freelist *fl);
  void geominit();
  void plotinit();

  // GS: removed the unused (always ==0) argument
  bool voronoi(/*int triangulate*/);
  void ref(Site *v);
  void deref(Site *v);
  void endpoint(Edge *e,int lr,Site * s);

  void ELdelete(Halfedge *he);
  Halfedge *ELleftbnd(VPoint *p);
  Halfedge *ELright(Halfedge *he);
  void makevertex(Site *v);
  
  void PQinsert(Halfedge *he,Site * v, double offset);
  void PQdelete(Halfedge *he);
  bool ELinitialize();
  void ELinsert(Halfedge *lb, Halfedge *newHe);
  Halfedge * ELgethash(int b);
  Halfedge *ELleft(Halfedge *he);
  Site *leftreg(Halfedge *he);
  bool PQinitialize();
  int PQbucket(Halfedge *he);
  void clip_line(Edge *e);
  char *myalloc(unsigned n);
  int right_of(Halfedge *el,VPoint *p);

  Site *rightreg(Halfedge *he);
  Edge *bisect(Site *s1, Site *s2);
  double dist(Site *s,Site *t);

  // GS: 'p' is unused and always ==0 (see also comment by
  //     S. O'Sullivan in the source file), so we remove it
  Site *intersect(Halfedge *el1, Halfedge *el2 /*, VPoint *p=0*/);

  Site *nextone();

  void pushGraphEdge(double x1, double y1, double x2, double y2, 
                     Site *s1, Site *s2);

  // Gregory Soyez: unused plotting methods
  // void openpl();
  // void circle(double x, double y, double radius);
  // void range(double minX, double minY, double maxX, double maxY);
  // 
  // void out_bisector(Edge *e);
  // void out_ep(Edge *e);
  // void out_vertex(Site *v);
  // void out_site(Site *s);
  // 
  // void out_triple(Site *s1, Site *s2,Site * s3);

  Freelist hfl;
  Halfedge *ELleftend, *ELrightend;
  int ELhashsize;
  
  int sorted, debug;
  double xmin, xmax, ymin, ymax, deltax, deltay;
  
  Site *sites;
  int nsites;
  int siteidx;
  int sqrt_nsites;
  int nvertices;
  Freelist sfl;
  Site *bottomsite;
  
  int nedges;
  Freelist efl;
  int PQhashsize;
  Halfedge *PQhash;
  int PQcount;
  int PQmin;
  
  int ntry, totalsearch;
  double pxmin, pxmax, pymin, pymax, cradius;
  int total_alloc;
  
  double borderMinX, borderMaxX, borderMinY, borderMaxY;
  
  FreeNodeArrayList* allMemoryList;
  FreeNodeArrayList* currentMemoryBlock;
  
  GraphEdge* allEdges;
  GraphEdge* iteratorEdges;
  
  double minDistanceBetweenSites;

  static LimitedWarning _warning_degeneracy;
};

int scomp(const void *p1,const void *p2);


FASTJET_END_NAMESPACE

#endif