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/* This file is part of the Gudhi Library - https://gudhi.inria.fr/ - which is released under MIT.
* See file LICENSE or go to https://gudhi.inria.fr/licensing/ for full license details.
* Author(s): Vincent Rouvreau
*
* Copyright (C) 2018 Inria
*
* Modification(s):
* - YYYY/MM Author: Description of the modification
*/
#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::clog << "#(" << vertex << ")#";
#endif // DEBUG_TRACES
}
Filtration_value radius = Gudhi::Minimal_enclosing_ball_radius()(points);
#ifdef DEBUG_TRACES
if (radius > cc_ptr_->max_radius()) std::clog << "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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