Added example stuff

git-svn-id: svn+ssh://scm.gforge.inria.fr/svnroot/gudhi/branches/witness@968 636b058d-ea47-450e-bf9e-a15bfbe3eedb

Former-commit-id: a769b41f7d2d784a2740c149da08dac8124e3df9

1 files changed, 126 insertions, 0 deletions

diff --git a/src/Witness_complex/example/witness_complex_sphere.cpp b/src/Witness_complex/example/witness_complex_sphere.cpp
new file mode 100644
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+++ b/src/Witness_complex/example/witness_complex_sphere.cpp
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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):       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 <iostream>
+#include <fstream>
+#include <ctime>
+#include <utility> 
+
+#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 "generators.h"
+
+using namespace Gudhi;
+
+typedef std::vector< Vertex_handle > typeVectorVertex;
+//typedef std::vector< std::vector <double> > Point_Vector;
+
+typedef Witness_complex< Simplex_tree<> > WitnessComplex;
+
+/**
+ * \brief Customized version of read_points
+ * which takes into account a possible nbP first line
+ *
+ */
+inline void
+read_points_cust ( std::string file_name , std::vector< std::vector< double > > & points)
+{  
+  std::ifstream in_file (file_name.c_str(),std::ios::in);
+  if(!in_file.is_open())
+    {
+      std::cerr << "Unable to open file " << file_name << std::endl;
+      return;
+    }
+  std::string line;
+  double x;
+  while( getline ( in_file , line ) )
+    {
+      std::vector< double > point;
+      std::istringstream iss( line );
+      while(iss >> x) { point.push_back(x); }
+      if (point.size() != 1)
+        points.push_back(point);
+    }
+  in_file.close();
+}
+
+/** 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 != 3)
+    {
+      std::cerr << "Usage: " << argv[0]
+                << " path_to_point_file nbL \n";
+      return 0;
+    }
+
+  std::string file_name   = argv[1];
+  int nbL       = atoi(argv[2]);
+  clock_t start, end;
+
+  // Construct the Simplex Tree
+  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;
+      Landmark_choice_by_random_point(point_vector, nbL, knn);
+      
+      // Compute witness complex
+      WitnessComplex(knn, simplex_tree, nbL, point_vector[0].size());
+      end = clock();
+      double time = (double)(end-start)/CLOCKS_PER_SEC;
+      std::cout << "Witness complex for " << nbL << " landmarks took "
+       << time << " s. \n";
+      l_time.push_back(std::make_pair(nbP,time));
+    }
+  write_data(l_time, "w_time.dat");
+}