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Weighted_alpha_complex_from_points.cpp
#include <gudhi/Alpha_complex.h>
// to construct a simplex_tree from alpha complex
#include <gudhi/Simplex_tree.h>
#include <CGAL/Epeck_d.h>
#include <iostream>
#include <vector>
// Explicit dimension 2 Epeck_d kernel
using Kernel = CGAL::Epeck_d< CGAL::Dimension_tag<3> >;
using Bare_point = Kernel::Point_d;
using Weighted_point = Kernel::Weighted_point_d;
using Vector_of_points = std::vector<Weighted_point>;
int main() {
// ----------------------------------------------------------------------------
// Init of a list of points and weights from a small molecule
// ----------------------------------------------------------------------------
Vector_of_points points;
points.emplace_back(Bare_point(1, -1, -1), 4.);
points.emplace_back(Bare_point(-1, 1, -1), 4.);
points.emplace_back(Bare_point(-1, -1, 1), 4.);
points.emplace_back(Bare_point(1, 1, 1), 4.);
points.emplace_back(Bare_point(2, 2, 2), 1.);
// ----------------------------------------------------------------------------
// Init of an alpha complex from the list of points
// ----------------------------------------------------------------------------
Gudhi::alpha_complex::Alpha_complex<Kernel, true> alpha_complex_from_weighted_points(points);
if (alpha_complex_from_weighted_points.create_complex(simplex)) {
// ----------------------------------------------------------------------------
// Display information about the alpha complex
// ----------------------------------------------------------------------------
std::clog << "Weighted alpha complex is of dimension " << simplex.dimension() <<
" - " << simplex.num_simplices() << " simplices - " <<
simplex.num_vertices() << " vertices." << std::endl;
std::clog << "Iterator on weighted alpha complex simplices in the filtration order, with [filtration value]:" << std::endl;
for (auto f_simplex : simplex.filtration_simplex_range()) {
std::clog << " ( ";
for (auto vertex : simplex.simplex_vertex_range(f_simplex)) {
std::clog << vertex << " ";
}
std::clog << ") -> " << "[" << simplex.filtration(f_simplex) << "] ";
std::clog << std::endl;
}
}
return 0;
}
Simplex Tree data structure for representing simplicial complexes.
Definition: Simplex_tree.h:83
Filtration_simplex_range const & filtration_simplex_range(Indexing_tag=Indexing_tag())
Returns a range over the simplices of the simplicial complex, in the order of the filtration.
Definition: Simplex_tree.h:275
Simplex_vertex_range simplex_vertex_range(Simplex_handle sh) const
Returns a range over the vertices of a simplex.
Definition: Simplex_tree.h:286
static Filtration_value filtration(Simplex_handle sh)
Returns the filtration value of a simplex.
Definition: Simplex_tree.h:539
size_t num_vertices() const
Returns the number of vertices in the complex.
Definition: Simplex_tree.h:576
int dimension(Simplex_handle sh)
Returns the dimension of a simplex.
Definition: Simplex_tree.h:609
size_t num_simplices()
returns the number of simplices in the simplex_tree.
Definition: Simplex_tree.h:587
Alpha complex data structure.
Definition: Alpha_complex.h:103
bool create_complex(SimplicialComplexForAlpha &complex, Filtration_value max_alpha_square=std::numeric_limits< Filtration_value >::infinity(), bool exact=false, bool default_filtration_value=false)
Inserts all Delaunay triangulation into the simplicial complex. It also computes the filtration value...
Definition: Alpha_complex.h:374