/* 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 .
*/
#ifndef SRC_BOTTLENECK_INCLUDE_GUDHI_PERSISTENCE_DIAGRAMS_GRAPH_H_
#define SRC_BOTTLENECK_INCLUDE_GUDHI_PERSISTENCE_DIAGRAMS_GRAPH_H_
#include
#include
#include
#include
#include
#include
#include
#include
namespace Gudhi {
namespace Bottleneck_distance {
/** \internal \brief Structure representing an euclidean bipartite graph containing
* the points from the two persistence diagrams (including the projections).
*
* \ingroup bottleneck_distance
*/
class Persistence_diagrams_graph {
public:
/** \internal \brief Initializer taking 2 Point (concept) ranges as parameters. */
template
static void initialize(const Persistence_diagram1& diag1, const Persistence_diagram2& diag2, double e);
/** \internal \brief Is the given point from U the projection of a point in V ? */
static bool on_the_u_diagonal(int u_point_index);
/** \internal \brief Is the given point from V the projection of a point in U ? */
static bool on_the_v_diagonal(int v_point_index);
/** \internal \brief Given a point from V, returns the corresponding (projection or projector) point in U. */
static int corresponding_point_in_u(int v_point_index);
/** \internal \brief Given a point from U, returns the corresponding (projection or projector) point in V. */
static int corresponding_point_in_v(int u_point_index);
/** \internal \brief Given a point from U and a point from V, returns the distance between those points. */
static double distance(int u_point_index, int v_point_index);
/** \internal \brief Returns size = |U| = |V|. */
static int size();
/** \internal \brief Returns the O(n^2) sorted distances between the points. */
static std::shared_ptr< std::vector > sorted_distances();
/** \internal \brief Returns an upper bound of the diameter of the convex hull */
static double diameter();
private:
static std::vector u;
static std::vector v;
static Internal_point get_u_point(int u_point_index);
static Internal_point get_v_point(int v_point_index);
friend class Naive_pnf;
friend class Cgal_pnf;
};
/** \internal \typedef \brief Shorter alias */
typedef Persistence_diagrams_graph G;
// static initialization
std::vector G::u = [] {return std::vector();}();
std::vector G::v = [] {return std::vector();}();
template
inline void G::initialize(const Persistence_diagram1 &diag1,
const Persistence_diagram2 &diag2, double e){
u.clear();
v.clear();
for (auto it = diag1.cbegin(); it != diag1.cend(); ++it)
if (it->second - it->first > e)
u.push_back(Internal_point(it->first, it->second, u.size()));
for (auto it = diag2.cbegin(); it != diag2.cend(); ++it)
if (it->second - it->first > e)
v.push_back(Internal_point(it->first, it->second, v.size()));
if (u.size() < v.size())
swap(u, v);
}
inline bool G::on_the_u_diagonal(int u_point_index) {
return u_point_index >= static_cast (u.size());
}
inline bool G::on_the_v_diagonal(int v_point_index) {
return v_point_index >= static_cast (v.size());
}
inline int G::corresponding_point_in_u(int v_point_index) {
return on_the_v_diagonal(v_point_index) ?
v_point_index - static_cast (v.size()) : v_point_index + static_cast (u.size());
}
inline int G::corresponding_point_in_v(int u_point_index) {
return on_the_u_diagonal(u_point_index) ?
u_point_index - static_cast (u.size()) : u_point_index + static_cast (v.size());
}
inline double G::distance(int u_point_index, int v_point_index) {
if (on_the_u_diagonal(u_point_index) && on_the_v_diagonal(v_point_index))
return 0;
Internal_point p_u = get_u_point(u_point_index);
Internal_point p_v = get_v_point(v_point_index);
return std::max(std::fabs(p_u.x() - p_v.x()), std::fabs(p_u.y() - p_v.y()));
}
inline int G::size() {
return static_cast (u.size() + v.size());
}
inline std::shared_ptr< std::vector > G::sorted_distances() {
// could be optimized
std::set sorted_distances;
sorted_distances.emplace(0.);
for (int u_point_index = 0; u_point_index < size(); ++u_point_index)
for (int v_point_index = 0; v_point_index < size(); ++v_point_index)
sorted_distances.emplace(distance(u_point_index, v_point_index));
std::shared_ptr< std::vector > sd_up(new std::vector(sorted_distances.cbegin(), sorted_distances.cend()));
return sd_up;
}
inline Internal_point G::get_u_point(int u_point_index) {
if (!on_the_u_diagonal(u_point_index))
return u.at(u_point_index);
Internal_point projector = v.at(corresponding_point_in_v(u_point_index));
double m = (projector.x() + projector.y()) / 2;
return Internal_point(m,m,u_point_index);
}
inline Internal_point G::get_v_point(int v_point_index) {
if (!on_the_v_diagonal(v_point_index))
return v.at(v_point_index);
Internal_point projector = u.at(corresponding_point_in_u(v_point_index));
double m = (projector.x() + projector.y()) / 2;
return Internal_point(m,m,v_point_index);
}
inline double G::diameter() {
double max = 0.;
for(auto it = u.cbegin(); it != u.cend(); it++)
max = std::max(max,it->y());
for(auto it = v.cbegin(); it != v.cend(); it++)
max = std::max(max,it->y());
return max;
}
} // namespace Bottleneck_distance
} // namespace Gudhi
#endif // SRC_BOTTLENECK_INCLUDE_GUDHI_PERSISTENCE_DIAGRAMS_GRAPH_H_