cgal/Spatial_searching/include/CGAL/Euclidean_distance.h

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// Copyright (c) 2002,2011 Utrecht University (The Netherlands).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org).
// 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 3 of the License, or (at your option) any later version.
//
// Licensees holding a valid commercial license may use this file in
// accordance with the commercial license agreement provided with the software.
//
// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
//
// $URL$
// $Id$
//
//
// Author(s) : Hans Tangelder (<hanst@cs.uu.nl>)
#ifndef CGAL_EUCLIDEAN_DISTANCE_H
#define CGAL_EUCLIDEAN_DISTANCE_H
#include <CGAL/Kd_tree_rectangle.h>
#include <CGAL/number_utils.h>
#include <CGAL/internal/Get_dimension_tag.h>
#include <vector>
namespace CGAL {
template <class SearchTraits>
class Euclidean_distance;
namespace internal{
template <class SearchTraits>
struct Spatial_searching_default_distance{
typedef ::CGAL::Euclidean_distance<SearchTraits> type;
};
} //namespace internal
template <class SearchTraits>
class Euclidean_distance {
SearchTraits traits;
public:
typedef typename SearchTraits::FT FT;
typedef typename SearchTraits::Point_d Point_d;
typedef Point_d Query_item;
typedef typename internal::Get_dimension_tag<SearchTraits>::Dimension D;
// default constructor
Euclidean_distance(const SearchTraits& traits_=SearchTraits()):traits(traits_) {}
// During the computation, if the partially-computed distance `pcd` gets greater or equal
// to `stop_if_geq_to_this`, the computation is stopped and `pcd` is returned
inline FT transformed_distance(const Query_item& q, const Point_d& p,
FT stop_if_geq_to_this = std::numeric_limits<FT>::max()) const
{
typename SearchTraits::Construct_cartesian_const_iterator_d construct_it = traits.construct_cartesian_const_iterator_d_object();
typename SearchTraits::Cartesian_const_iterator_d p_begin = construct_it(p), p_end = construct_it(p, 0);
return transformed_distance(q, p_begin, p_end, stop_if_geq_to_this);
}
// During the computation, if the partially-computed distance `pcd` gets greater or equal
// to `stop_if_geq_to_this`, the computation is stopped and `pcd` is returned
template <typename Coord_iterator>
inline FT transformed_distance(const Query_item& q,
Coord_iterator it_coord_begin, Coord_iterator it_coord_end,
FT stop_if_geq_to_this = std::numeric_limits<FT>::max()) const
{
return transformed_distance(q, it_coord_begin, it_coord_end, stop_if_geq_to_this, D());
}
// Dynamic version for runtime dimension, taking iterators on coordinates as parameters
// During the computation, if the partially-computed distance `pcd` gets greater or equal
// to `stop_if_geq_to_this`, the computation is stopped and `pcd` is returned
template <typename Coord_iterator>
inline FT transformed_distance(const Query_item& q,
Coord_iterator it_coord_begin, Coord_iterator it_coord_end,
FT stop_if_geq_to_this, Dynamic_dimension_tag) const
{
FT distance = FT(0);
typename SearchTraits::Construct_cartesian_const_iterator_d construct_it = traits.construct_cartesian_const_iterator_d_object();
typename SearchTraits::Cartesian_const_iterator_d qit = construct_it(q),
qe = construct_it(q, 1);
if (qe - qit >= 4)
{
// Every 4 coordinates, the current partially-computed distance
// is compared to stop_if_geq_to_this
// Note: the concept SearchTraits specifies that Cartesian_const_iterator_d
// must be a random-access iterator
typename SearchTraits::Cartesian_const_iterator_d qe_minus_3 = qe - 3;
for (; qit < qe_minus_3; ++qit, ++it_coord_begin) {
FT diff = (*qit) - (*it_coord_begin);
distance += diff*diff;
++qit; ++it_coord_begin;
diff = (*qit) - (*it_coord_begin);
distance += diff*diff;
++qit; ++it_coord_begin;
diff = (*qit) - (*it_coord_begin);
distance += diff*diff;
if (distance >= stop_if_geq_to_this)
return distance;
++qit; ++it_coord_begin;
diff = (*qit) - (*it_coord_begin);
distance += diff*diff;
}
}
for (; qit != qe; ++qit, ++it_coord_begin)
{
FT diff = (*qit) - (*it_coord_begin);
distance += diff*diff;
}
return distance;
}
// Generic version for DIM > 3 taking iterators on coordinates as parameters
// During the computation, if the partially-computed distance `pcd` gets greater or equal
// to `stop_if_geq_to_this`, the computation is stopped and `pcd` is returned
template <int DIM, typename Coord_iterator>
inline FT transformed_distance(const Query_item& q,
Coord_iterator it_coord_begin, Coord_iterator it_coord_end,
FT stop_if_geq_to_this, Dimension_tag<DIM>) const
{
FT distance = FT(0);
typename SearchTraits::Construct_cartesian_const_iterator_d construct_it = traits.construct_cartesian_const_iterator_d_object();
typename SearchTraits::Cartesian_const_iterator_d qit = construct_it(q),
qe = construct_it(q, 1);
if (qe - qit >= 4)
{
// Every 4 coordinates, the current partially-computed distance
// is compared to stop_if_geq_to_this
// Note: the concept SearchTraits specifies that Cartesian_const_iterator_d
// must be a random-access iterator
typename SearchTraits::Cartesian_const_iterator_d qe_minus_3 = qe - 3;
for (; qit < qe_minus_3; ++qit, ++it_coord_begin) {
FT diff = (*qit) - (*it_coord_begin);
distance += diff*diff;
++qit; ++it_coord_begin;
diff = (*qit) - (*it_coord_begin);
distance += diff*diff;
++qit; ++it_coord_begin;
diff = (*qit) - (*it_coord_begin);
distance += diff*diff;
if (distance >= stop_if_geq_to_this)
return distance;
++qit; ++it_coord_begin;
diff = (*qit) - (*it_coord_begin);
distance += diff*diff;
}
}
for (; qit != qe; ++qit, ++it_coord_begin)
{
FT diff = (*qit) - (*it_coord_begin);
distance += diff*diff;
}
return distance;
}
//DIM = 2 loop unrolled
template <typename Coord_iterator>
inline FT transformed_distance(const Query_item& q,
Coord_iterator it_coord_begin, Coord_iterator /*unused*/,
FT /*unused*/, Dimension_tag<2>) const {
typename SearchTraits::Construct_cartesian_const_iterator_d construct_it = traits.construct_cartesian_const_iterator_d_object();
typename SearchTraits::Cartesian_const_iterator_d qit = construct_it(q);
FT distance = square(*qit - *it_coord_begin);
qit++; it_coord_begin++;
distance += square(*qit - *it_coord_begin);
return distance;
}
//DIM = 3 loop unrolled
template <typename Coord_iterator>
inline FT transformed_distance(const Query_item& q,
Coord_iterator it_coord_begin, Coord_iterator /*unused*/,
FT /*unused*/, Dimension_tag<3>) const {
typename SearchTraits::Construct_cartesian_const_iterator_d construct_it = traits.construct_cartesian_const_iterator_d_object();
typename SearchTraits::Cartesian_const_iterator_d qit = construct_it(q);
FT distance = square(*qit - *it_coord_begin);
qit++; it_coord_begin++;
distance += square(*qit - *it_coord_begin);
qit++; it_coord_begin++;
distance += square(*qit - *it_coord_begin);
return distance;
}
inline FT min_distance_to_rectangle(const Query_item& q,
const Kd_tree_rectangle<FT,D>& r) const {
FT distance = FT(0);
typename SearchTraits::Construct_cartesian_const_iterator_d construct_it=traits.construct_cartesian_const_iterator_d_object();
typename SearchTraits::Cartesian_const_iterator_d qit = construct_it(q),
qe = construct_it(q,1);
for(unsigned int i = 0;qit != qe; i++, qit++){
if((*qit) < r.min_coord(i))
distance +=
(r.min_coord(i)-(*qit))*(r.min_coord(i)-(*qit));
else if ((*qit) > r.max_coord(i))
distance +=
((*qit)-r.max_coord(i))*((*qit)-r.max_coord(i));
}
return distance;
}
inline FT min_distance_to_rectangle(const Query_item& q,
const Kd_tree_rectangle<FT,D>& r,std::vector<FT>& dists) const {
FT distance = FT(0);
typename SearchTraits::Construct_cartesian_const_iterator_d construct_it=traits.construct_cartesian_const_iterator_d_object();
typename SearchTraits::Cartesian_const_iterator_d qit = construct_it(q),
qe = construct_it(q,1);
for(unsigned int i = 0;qit != qe; i++, qit++){
if((*qit) < r.min_coord(i)){
dists[i] = (r.min_coord(i)-(*qit));
distance += dists[i] * dists[i];
}
else if ((*qit) > r.max_coord(i)){
dists[i] = ((*qit)-r.max_coord(i));
distance += dists[i] * dists[i];
}
}
return distance;
}
inline FT max_distance_to_rectangle(const Query_item& q,
const Kd_tree_rectangle<FT,D>& r) const {
FT distance=FT(0);
typename SearchTraits::Construct_cartesian_const_iterator_d construct_it=traits.construct_cartesian_const_iterator_d_object();
typename SearchTraits::Cartesian_const_iterator_d qit = construct_it(q),
qe = construct_it(q,1);
for(unsigned int i = 0;qit != qe; i++, qit++){
if ((*qit) <= (r.min_coord(i)+r.max_coord(i))/FT(2.0))
distance += (r.max_coord(i)-(*qit))*(r.max_coord(i)-(*qit));
else
distance += ((*qit)-r.min_coord(i))*((*qit)-r.min_coord(i));
};
return distance;
}
inline FT max_distance_to_rectangle(const Query_item& q,
const Kd_tree_rectangle<FT,D>& r,std::vector<FT>& dists ) const {
FT distance=FT(0);
typename SearchTraits::Construct_cartesian_const_iterator_d construct_it=traits.construct_cartesian_const_iterator_d_object();
typename SearchTraits::Cartesian_const_iterator_d qit = construct_it(q),
qe = construct_it(q,1);
for(unsigned int i = 0;qit != qe; i++, qit++){
if ((*qit) <= (r.min_coord(i)+r.max_coord(i))/FT(2.0)){
dists[i] = (r.max_coord(i)-(*qit));
distance += dists[i] * dists[i];
}
else{
dists[i] = ((*qit)-r.min_coord(i));
distance += dists[i] * dists[i];
}
};
return distance;
}
inline FT new_distance(FT dist, FT old_off, FT new_off,
int /* cutting_dimension */) const {
FT new_dist = dist + (new_off*new_off - old_off*old_off);
return new_dist;
}
inline FT transformed_distance(FT d) const {
return d*d;
}
inline FT inverse_of_transformed_distance(FT d) const {
return CGAL::sqrt(d);
}
}; // class Euclidean_distance
} // namespace CGAL
#endif // EUCLIDEAN_DISTANCE_H