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/* This file is part of the Gudhi Library. The Gudhi library
* (Geometric Understanding in Higher Dimensions) is a generic C++
* library for computational topology.
*
* Author(s): David Salinas
*
* Copyright (C) 2014 INRIA Sophia Antipolis-Mediterranee (France)
*
* This program 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 3 of the License, or
* (at your option) any later version.
*
* This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#ifndef UTILS_K_NEAREST_BUILDER_H_
#define UTILS_K_NEAREST_BUILDER_H_
#include <CGAL/Euclidean_distance.h>
#include <CGAL/Orthogonal_k_neighbor_search.h>
#include <CGAL/Search_traits_d.h>
#include <CGAL/Search_traits_adapter.h>
#include <CGAL/property_map.h>
#include <unordered_map>
#include <list>
#include <utility>
#include "utils/UI_utils.h"
#include "model/Complex_typedefs.h"
template<typename SkBlComplex> class K_nearest_builder {
private:
typedef Geometry_trait Kernel;
typedef Point Point_d;
typedef std::pair<Point_d, unsigned> Point_d_with_id;
typedef CGAL::Search_traits_d<Kernel> Traits_base;
typedef CGAL::Search_traits_adapter<Point_d_with_id, CGAL::First_of_pair_property_map<Point_d_with_id>,
Traits_base> Traits;
typedef CGAL::Orthogonal_k_neighbor_search<Traits> Neighbor_search;
typedef Neighbor_search::Tree Tree;
typedef Neighbor_search::Distance Distance;
SkBlComplex& complex_;
public:
/**
* @brief Modify complex to be the expansion of the k-nearest neighbor
* symetric graph.
*/
K_nearest_builder(SkBlComplex& complex, unsigned k) : complex_(complex) {
complex.keep_only_vertices();
compute_edges(k);
}
private:
double squared_eucl_distance(const Point& p1, const Point& p2) const {
return Geometry_trait::Squared_distance_d()(p1, p2);
}
void compute_edges(unsigned k) {
std::list<Point_d_with_id> points_with_id;
for (auto v : complex_.vertex_range()) {
Point_d_with_id point_v(complex_.point(v), v.vertex);
points_with_id.push_back(point_v);
}
Tree tree(points_with_id.begin(), points_with_id.end());
typedef typename SkBlComplex::Vertex_handle Vertex_handle;
for (auto p : complex_.vertex_range()) {
Neighbor_search search(tree, complex_.point(p), k + 1);
for (auto it = ++search.begin(); it != search.end(); ++it) {
Vertex_handle q(std::get<1>(it->first));
if (p != q && complex_.contains_vertex(p) && complex_.contains_vertex(q))
complex_.add_edge(p, q);
}
}
}
};
#endif // UTILS_K_NEAREST_BUILDER_H_
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