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#include <gudhi/Cech_complex.h>
#include <gudhi/Simplex_tree.h>
#include <CGAL/Epeck_d.h> // For EXACT or SAFE version
#include <iostream>
#include <string>
#include <vector>
int main() {
// Type definitions
using Simplex_tree = Gudhi::Simplex_tree<Gudhi::Simplex_tree_options_fast_persistence>;
using Filtration_value = Simplex_tree::Filtration_value;
using Kernel = CGAL::Epeck_d<CGAL::Dimension_tag<2>>;
using Point = typename Kernel::Point_d;
using Point_cloud = std::vector<Point>;
using Cech_complex = Gudhi::cech_complex::Cech_complex<Kernel, Simplex_tree>;
Point_cloud points;
points.emplace_back(1., 0.); // 0
points.emplace_back(0., 1.); // 1
points.emplace_back(2., 1.); // 2
points.emplace_back(3., 2.); // 3
points.emplace_back(0., 3.); // 4
points.emplace_back(3. + std::sqrt(3.), 3.); // 5
points.emplace_back(1., 4.); // 6
points.emplace_back(3., 4.); // 7
points.emplace_back(2., 4. + std::sqrt(3.)); // 8
points.emplace_back(0., 4.); // 9
points.emplace_back(-0.5, 2.); // 10
// ----------------------------------------------------------------------------
// Init of a Cech complex from points
// ----------------------------------------------------------------------------
Filtration_value max_radius = 1.;
Cech_complex cech_complex_from_points(points, max_radius);
Simplex_tree stree;
cech_complex_from_points.create_complex(stree, 2);
// ----------------------------------------------------------------------------
// Display information about the one skeleton Cech complex
// ----------------------------------------------------------------------------
std::clog << "Cech complex is of dimension " << stree.dimension() << " - " << stree.num_simplices() << " simplices - "
<< stree.num_vertices() << " vertices." << std::endl;
std::clog << "Iterator on Cech complex simplices in the filtration order, with [filtration value]:" << std::endl;
for (auto f_simplex : stree.filtration_simplex_range()) {
std::clog << " ( ";
for (auto vertex : stree.simplex_vertex_range(f_simplex)) {
std::clog << vertex << " ";
}
std::clog << ") -> "
<< "[" << stree.filtration(f_simplex) << "] ";
std::clog << std::endl;
}
return 0;
}
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