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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): David Salinas
+ *
+ * Copyright (C) 2014 Inria
+ *
+ * Modification(s):
+ * - YYYY/MM Author: Description of the modification
+ */
+
+#include <gudhi/Skeleton_blocker.h>
+#include <gudhi/Clock.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string>
+#include <fstream>
+#include <sstream>
+
+typedef Gudhi::skeleton_blocker::Skeleton_blocker_simple_traits Traits;
+typedef Gudhi::skeleton_blocker::Skeleton_blocker_complex<Traits> Complex;
+typedef Complex::Vertex_handle Vertex_handle;
+typedef Complex::Simplex Simplex;
+
+Complex build_complete_complex(int n) {
+ // build a full complex with n vertices and 2^n-1 simplices
+ Complex complex;
+ for (int i = 0; i < n; i++)
+ complex.add_vertex();
+ for (int i = 0; i < n; i++)
+ for (int j = 0; j < i; j++)
+ complex.add_edge_without_blockers(Vertex_handle(i), Vertex_handle(j));
+ return complex;
+}
+
+int main(int argc, char *argv[]) {
+ Gudhi::Clock skbl_chrono("Time to build the complete complex, enumerate simplices and Euler Characteristic");
+ const int n = 15;
+
+ // build a full complex with n vertices and 2^n-1 simplices
+ Complex complex(build_complete_complex(n));
+
+ // this is just to illustrate iterators, to count number of vertices
+ // or edges, complex.num_vertices() and complex.num_edges() are
+ // more appropriated!
+ unsigned num_vertices = 0;
+ for (auto v : complex.vertex_range()) {
+ std::cout << "Vertex " << v << std::endl;
+ ++num_vertices;
+ }
+
+ // such loop can also be done directly with distance as iterators are STL compliant
+ auto edges = complex.edge_range();
+ unsigned num_edges = std::distance(edges.begin(), edges.end());
+
+ unsigned euler = 0;
+ unsigned num_simplices = 0;
+ // we use a reference to a simplex instead of a copy
+ // value here because a simplex is a set of integers
+ // and copying it cost time
+ for (const Simplex & s : complex.complex_simplex_range()) {
+ ++num_simplices;
+ if (s.dimension() % 2 == 0)
+ euler += 1;
+ else
+ euler -= 1;
+ }
+ std::cout << "Saw " << num_vertices << " vertices, " << num_edges << " edges and " << num_simplices << " simplices"
+ << std::endl;
+ std::cout << "The Euler Characteristic is " << euler << std::endl;
+ std::cout << skbl_chrono;
+ return EXIT_SUCCESS;
+}