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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): Francois Godi
*
* Copyright (C) 2015 INRIA Sophia-Antipolis (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 SRC_BOTTLENECK_INCLUDE_GUDHI_NEIGHBORS_FINDER_H_
#define SRC_BOTTLENECK_INCLUDE_GUDHI_NEIGHBORS_FINDER_H_
#include <unordered_set>
#include <list>
#include "Planar_neighbors_finder.h"
namespace Gudhi {
namespace bottleneck {
/** \internal \brief data structure used to find any point (including projections) in V near to a query point from U
* (which can be a projection).
*
* V points have to be added manually using their index and before the first pull. A neighbor pulled is automatically removed.
*
* \ingroup bottleneck_distance
*/
class Neighbors_finder {
public:
/** \internal \brief Constructor taking the near distance definition as parameter. */
Neighbors_finder(double r);
/** \internal \brief A point added will be possibly pulled. */
void add(int v_point_index);
/** \internal \brief Returns and remove a V point near to the U point given as parameter, null_point_index() if there isn't such a point. */
int pull_near(int u_point_index);
/** \internal \brief Returns and remove all the V points near to the U point given as parameter. */
std::unique_ptr< std::list<int> > pull_all_near(int u_point_index);
private:
const double r;
Planar_neighbors_finder planar_neighbors_f;
std::unordered_set<int> projections_f;
void remove(int v_point_index);
bool contains(int v_point_index);
};
Neighbors_finder::Neighbors_finder(double r) :
r(r), planar_neighbors_f(r), projections_f() { }
inline void Neighbors_finder::add(int v_point_index) {
if (G::on_the_v_diagonal(v_point_index))
projections_f.emplace(v_point_index);
else
planar_neighbors_f.add(v_point_index);
}
inline void Neighbors_finder::remove(int v_point_index) {
if(v_point_index == null_point_index())
return;
if (G::on_the_v_diagonal(v_point_index))
projections_f.erase(v_point_index);
else
planar_neighbors_f.remove(v_point_index);
}
inline bool Neighbors_finder::contains(int v_point_index) {
return planar_neighbors_f.contains(v_point_index) || (projections_f.count(v_point_index)>0);
}
inline int Neighbors_finder::pull_near(int u_point_index) {
int tmp;
int c = G::corresponding_point_in_v(u_point_index);
if (G::on_the_u_diagonal(u_point_index) && !projections_f.empty())
//All projections are at distance 0
tmp = *projections_f.cbegin();
else if (contains(c) && (G::distance(u_point_index, c) <= r))
//Is the query point near to its projection ?
tmp = c;
else
//Is the query point near to a V point in the plane ?
tmp = planar_neighbors_f.pull_near(u_point_index);
remove(tmp);
return tmp;
}
inline std::unique_ptr< std::list<int> > Neighbors_finder::pull_all_near(int u_point_index) {
std::unique_ptr< std::list<int> > all_pull = std::move(planar_neighbors_f.pull_all_near(u_point_index));
int last_pull = pull_near(u_point_index);
while (last_pull != null_point_index()) {
all_pull->emplace_back(last_pull);
last_pull = pull_near(u_point_index);
}
return all_pull;
}
} // namespace bottleneck
} // namespace Gudhi
#endif // SRC_BOTTLENECK_INCLUDE_GUDHI_NEIGHBORS_FINDER_H_
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