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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/>.
*/
#include <gudhi/Cech_complex.h>
#include <gudhi/Simplex_tree.h>
#include <gudhi/distance_functions.h>
#include <iostream>
#include <string>
#include <vector>
#include <array>
int main() {
// Type definitions
using Point_cloud = std::vector<std::array<double, 2>>;
using Simplex_tree = Gudhi::Simplex_tree<Gudhi::Simplex_tree_options_fast_persistence>;
using Filtration_value = Simplex_tree::Filtration_value;
using Cech_complex = Gudhi::cech_complex::Cech_complex<Simplex_tree, Point_cloud>;
Point_cloud points;
points.push_back({1.0, 1.0});
points.push_back({7.0, 0.0});
points.push_back({4.0, 6.0});
points.push_back({9.0, 6.0});
points.push_back({0.0, 14.0});
points.push_back({2.0, 19.0});
points.push_back({9.0, 17.0});
// ----------------------------------------------------------------------------
// Init of a Cech complex from points
// ----------------------------------------------------------------------------
// 7.1 is a magic number to force one blocker, and one non-blocker
Filtration_value threshold = 7.1;
Cech_complex cech_complex_from_points(points, threshold, Gudhi::Euclidean_distance());
Simplex_tree stree;
cech_complex_from_points.create_complex(stree, 2);
// ----------------------------------------------------------------------------
// Display information about the one skeleton Cech complex
// ----------------------------------------------------------------------------
std::cout << "Cech complex is of dimension " << stree.dimension() <<
" - " << stree.num_simplices() << " simplices - " <<
stree.num_vertices() << " vertices." << std::endl;
std::cout << "Iterator on Cech complex simplices in the filtration order, with [filtration value]:" <<
std::endl;
for (auto f_simplex : stree.filtration_simplex_range()) {
std::cout << " ( ";
for (auto vertex : stree.simplex_vertex_range(f_simplex)) {
std::cout << vertex << " ";
}
std::cout << ") -> " << "[" << stree.filtration(f_simplex) << "] ";
std::cout << std::endl;
}
return 0;
}
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