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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): Vincent Rouvreau
*
* Copyright (C) 2018 Inria
*
* 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 CECH_COMPLEX_BLOCKER_H_
#define CECH_COMPLEX_BLOCKER_H_
#include <gudhi/distance_functions.h> // for Gudhi::Minimal_enclosing_ball_radius
#include <iostream>
#include <vector>
#include <cmath> // for std::sqrt
namespace Gudhi {
namespace cech_complex {
/** \internal
* \class Cech_blocker
* \brief Čech complex blocker.
*
* \ingroup cech_complex
*
* \details
* Čech blocker is an oracle constructed from a Cech_complex and a simplicial complex.
*
* \tparam SimplicialComplexForProximityGraph furnishes `Simplex_handle` and `Filtration_value` type definition,
* `simplex_vertex_range(Simplex_handle sh)`and `assign_filtration(Simplex_handle sh, Filtration_value filt)` methods.
*
* \tparam Chech_complex is required by the blocker.
*/
template <typename SimplicialComplexForCech, typename Cech_complex>
class Cech_blocker {
private:
using Point_cloud = typename Cech_complex::Point_cloud;
using Simplex_handle = typename SimplicialComplexForCech::Simplex_handle;
using Filtration_value = typename SimplicialComplexForCech::Filtration_value;
public:
/** \internal \brief Čech complex blocker operator() - the oracle - assigns the filtration value from the simplex
* radius and returns if the simplex expansion must be blocked.
* \param[in] sh The Simplex_handle.
* \return true if the simplex radius is greater than the Cech_complex max_radius*/
bool operator()(Simplex_handle sh) {
Point_cloud points;
for (auto vertex : sc_ptr_->simplex_vertex_range(sh)) {
points.push_back(cc_ptr_->get_point(vertex));
#ifdef DEBUG_TRACES
std::cout << "#(" << vertex << ")#";
#endif // DEBUG_TRACES
}
Filtration_value radius = Gudhi::Minimal_enclosing_ball_radius()(points);
#ifdef DEBUG_TRACES
if (radius > cc_ptr_->max_radius()) std::cout << "radius > max_radius => expansion is blocked\n";
#endif // DEBUG_TRACES
sc_ptr_->assign_filtration(sh, radius);
return (radius > cc_ptr_->max_radius());
}
/** \internal \brief Čech complex blocker constructor. */
Cech_blocker(SimplicialComplexForCech* sc_ptr, Cech_complex* cc_ptr) : sc_ptr_(sc_ptr), cc_ptr_(cc_ptr) {}
private:
SimplicialComplexForCech* sc_ptr_;
Cech_complex* cc_ptr_;
};
} // namespace cech_complex
} // namespace Gudhi
#endif // CECH_COMPLEX_BLOCKER_H_
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