4 files changed, 253 insertions, 0 deletions
diff --git a/example/Skeleton_blocker/CMakeLists.txt b/example/Skeleton_blocker/CMakeLists.txt
new file mode 100644
index 00000000..cc7f37f3
--- /dev/null
+++ b/example/Skeleton_blocker/CMakeLists.txt
@@ -0,0 +1,12 @@
+cmake_minimum_required(VERSION 2.6)
+project(Skeleton_blocker_examples)
+
+add_executable(SkeletonBlockerFromSimplices Skeleton_blocker_from_simplices.cpp)
+add_executable(SkeletonBlockerIteration Skeleton_blocker_iteration.cpp)
+add_executable(SkeletonBlockerLink Skeleton_blocker_link.cpp)
+
+target_link_libraries(SkeletonBlockerIteration ${Boost_TIMER_LIBRARY} ${Boost_SYSTEM_LIBRARY})
+
+add_test(SkeletonBlockerFromSimplices ${CMAKE_CURRENT_BINARY_DIR}/SkeletonBlockerFromSimplices)
+add_test(SkeletonBlockerIteration ${CMAKE_CURRENT_BINARY_DIR}/SkeletonBlockerIteration)
+add_test(SkeletonBlockerLink ${CMAKE_CURRENT_BINARY_DIR}/SkeletonBlockerLink)
diff --git a/example/Skeleton_blocker/Skeleton_blocker_from_simplices.cpp b/example/Skeleton_blocker/Skeleton_blocker_from_simplices.cpp
new file mode 100644
index 00000000..171f35f2
--- /dev/null
+++ b/example/Skeleton_blocker/Skeleton_blocker_from_simplices.cpp
@@ -0,0 +1,80 @@
+/*    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):       David Salinas
+ *
+ *    Copyright (C) 2014  INRIA Sophia Antipolis-Mediterranee (France)
+ *
+ *    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/Skeleton_blocker.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string>
+#include <fstream>
+#include <sstream>
+#include <vector>
+
+using namespace std;
+using namespace Gudhi;
+using namespace skeleton_blocker;
+
+typedef Skeleton_blocker_complex<Skeleton_blocker_simple_traits> Complex;
+typedef Complex::Vertex_handle Vertex_handle;
+typedef Complex::Simplex Simplex;
+
+int main(int argc, char *argv[]) {
+  std::vector<Simplex> simplices;
+
+  // add 4 triangles of a tetrahedron 0123
+  simplices.push_back(Simplex(Vertex_handle(0), Vertex_handle(1), Vertex_handle(2)));
+  simplices.push_back(Simplex(Vertex_handle(1), Vertex_handle(2), Vertex_handle(3)));
+  simplices.push_back(Simplex(Vertex_handle(3), Vertex_handle(0), Vertex_handle(2)));
+  simplices.push_back(Simplex(Vertex_handle(3), Vertex_handle(0), Vertex_handle(1)));
+
+  // get complex from top faces
+  Complex complex(make_complex_from_top_faces<Complex>(simplices.begin(), simplices.end()));
+
+
+  std::cout << "Simplices:" << std::endl;
+  for (const Simplex & s : complex.complex_simplex_range())
+    std::cout << s << " ";
+  std::cout << std::endl;
+
+  // One blocker as simplex 0123 is not in the complex but all its proper faces are.
+  std::cout << "Blockers: " << complex.blockers_to_string() << std::endl;
+
+  // now build a complex from its full list of simplices
+  simplices.clear();
+  simplices.push_back(Simplex(Vertex_handle(0)));
+  simplices.push_back(Simplex(Vertex_handle(1)));
+  simplices.push_back(Simplex(Vertex_handle(2)));
+  simplices.push_back(Simplex(Vertex_handle(0), Vertex_handle(1)));
+  simplices.push_back(Simplex(Vertex_handle(1), Vertex_handle(2)));
+  simplices.push_back(Simplex(Vertex_handle(2), Vertex_handle(0)));
+  complex = Complex(simplices.begin(), simplices.end());
+
+  std::cout << "Simplices:" << std::endl;
+  for (const Simplex & s : complex.complex_simplex_range())
+    std::cout << s << " ";
+  std::cout << std::endl;
+
+  // One blocker as simplex 012 is not in the complex but all its proper faces are.
+  std::cout << "Blockers: " << complex.blockers_to_string() << std::endl;
+
+  return EXIT_SUCCESS;
+}
diff --git a/example/Skeleton_blocker/Skeleton_blocker_iteration.cpp b/example/Skeleton_blocker/Skeleton_blocker_iteration.cpp
new file mode 100644
index 00000000..8d9d1a67
--- /dev/null
+++ b/example/Skeleton_blocker/Skeleton_blocker_iteration.cpp
@@ -0,0 +1,90 @@
+/*    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):       David Salinas
+ *
+ *    Copyright (C) 2014  INRIA Sophia Antipolis-Mediterranee (France)
+ *
+ *    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/Skeleton_blocker.h>
+
+#include <boost/timer/timer.hpp>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string>
+#include <fstream>
+#include <sstream>
+
+
+using namespace std;
+using namespace Gudhi;
+using namespace skeleton_blocker;
+
+typedef Skeleton_blocker_complex<Skeleton_blocker_simple_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[]) {
+  boost::timer::auto_cpu_timer t;
+
+  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;
+  return EXIT_SUCCESS;
+}
diff --git a/example/Skeleton_blocker/Skeleton_blocker_link.cpp b/example/Skeleton_blocker/Skeleton_blocker_link.cpp
new file mode 100644
index 00000000..1f937170
--- /dev/null
+++ b/example/Skeleton_blocker/Skeleton_blocker_link.cpp
@@ -0,0 +1,71 @@
+/*    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):       David Salinas
+ *
+ *    Copyright (C) 2014  INRIA Sophia Antipolis-Mediterranee (France)
+ *
+ *    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/Skeleton_blocker.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string>
+#include <fstream>
+#include <sstream>
+
+using namespace std;
+using namespace Gudhi;
+using namespace skeleton_blocker;
+
+typedef Skeleton_blocker_complex<Skeleton_blocker_simple_traits> Complex;
+typedef Complex::Vertex_handle Vertex_handle;
+typedef Complex::Root_vertex_handle Root_vertex_handle;
+typedef Complex::Simplex Simplex;
+
+int main(int argc, char *argv[]) {
+  // build a full complex with 4 vertices and 2^4-1 simplices
+
+  // Create a complex with four vertices (0,1,2,3)
+  Complex complex;
+
+  // Add a tetrahedron to this complex
+  Simplex tetrahedron(Vertex_handle(0), Vertex_handle(1), Vertex_handle(2), Vertex_handle(3));
+  complex.add_simplex(tetrahedron);
+
+  cout << "complex:" << complex.to_string() << endl;
+
+  // build the link of vertex 1, eg a triangle {0,2,3}
+  auto link = complex.link(Vertex_handle(1));
+  cout << "link:" << link.to_string() << endl;
+
+  // Internally link is a subcomplex of 'complex' and its vertices are stored in a vector.
+  // They can be accessed via Vertex_handle(x) where x is an index of the vector.
+  // In that example, link has three vertices and thus it contains only
+  // Vertex_handle(0),Vertex_handle(1) and Vertex_handle(2) are).
+  for (int i = 0; i < 5; ++i)
+    cout << "link.contains_vertex(Vertex_handle(" << i << ")):" << link.contains_vertex(Vertex_handle(i)) << endl;
+  cout << endl;
+
+  // To access to the initial vertices eg (0,1,2,3,4),  Root_vertex_handle must be used.
+  // For instance, to test if the link contains the vertex that was labeled i:
+  for (int i = 0; i < 5; ++i)
+    cout << "link.contains_vertex(Root_vertex_handle(" << i << ")):" <<
+        link.contains_vertex(Root_vertex_handle(i)) << endl;
+
+  return EXIT_SUCCESS;
+}