1 files changed, 90 insertions, 0 deletions
diff --git a/example/Witness_complex/witness_complex_sphere.cpp b/example/Witness_complex/witness_complex_sphere.cpp
new file mode 100644
index 00000000..b26c9f36
--- /dev/null
+++ b/example/Witness_complex/witness_complex_sphere.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):       Siargey Kachanovich
+ *
+ *    Copyright (C) 2015  INRIA Sophia Antipolis-Méditerranée (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/>.
+ */
+#define BOOST_PARAMETER_MAX_ARITY 12
+
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <gudhi/Simplex_tree.h>
+#include <gudhi/Witness_complex.h>
+#include <gudhi/Landmark_choice_by_random_point.h>
+#include <gudhi/reader_utils.h>
+
+#include <iostream>
+#include <fstream>
+#include <ctime>
+#include <utility>
+#include <string>
+#include <vector>
+
+#include "generators.h"
+
+/** Write a gnuplot readable file.
+ *  Data range is a random access range of pairs (arg, value)
+ */
+template < typename Data_range >
+void write_data(Data_range & data, std::string filename) {
+  std::ofstream ofs(filename, std::ofstream::out);
+  for (auto entry : data)
+    ofs << entry.first << ", " << entry.second << "\n";
+  ofs.close();
+}
+
+int main(int argc, char * const argv[]) {
+  if (argc != 2) {
+    std::cerr << "Usage: " << argv[0]
+        << " number_of_landmarks \n";
+    return 0;
+  }
+
+  int number_of_landmarks = atoi(argv[1]);
+  clock_t start, end;
+
+  // Construct the Simplex Tree
+  Gudhi::Simplex_tree<> simplex_tree;
+
+  std::vector< std::pair<int, double> > l_time;
+
+  // Read the point file
+  for (int nbP = 500; nbP < 10000; nbP += 500) {
+    Point_Vector point_vector;
+    generate_points_sphere(point_vector, nbP, 4);
+    std::cout << "Successfully generated " << point_vector.size() << " points.\n";
+    std::cout << "Ambient dimension is " << point_vector[0].size() << ".\n";
+
+    // Choose landmarks
+    start = clock();
+    std::vector<std::vector< int > > knn;
+    Gudhi::witness_complex::landmark_choice_by_random_point(point_vector, number_of_landmarks, knn);
+
+    // Compute witness complex
+    Gudhi::witness_complex::witness_complex(knn, number_of_landmarks, point_vector[0].size(), simplex_tree);
+    end = clock();
+    double time = static_cast<double>(end - start) / CLOCKS_PER_SEC;
+    std::cout << "Witness complex for " << number_of_landmarks << " landmarks took "
+        << time << " s. \n";
+    std::cout << "Number of simplices is: " << simplex_tree.num_simplices() << "\n";
+    l_time.push_back(std::make_pair(nbP, time));
+  }
+  write_data(l_time, "w_time.dat");
+}