git-svn-id: svn+ssh://scm.gforge.inria.fr/svnroot/gudhi/branches/Nerve_GIC@2018 636b058d-ea47-450e-bf9e-a15bfbe3eedb

Former-commit-id: 0741bf2fb85724b6c9ef28f946e5e2a0489adaed

1 files changed, 82 insertions, 0 deletions

diff --git a/src/Nerve_GIC/example/simple_GIC.cpp b/src/Nerve_GIC/example/simple_GIC.cpp
new file mode 100644
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+++ b/src/Nerve_GIC/example/simple_GIC.cpp
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+#include <gudhi/Rips_complex.h>
+// to construct Rips_complex from a OFF file of points
+#include <gudhi/Points_off_io.h>
+#include <gudhi/Simplex_tree.h>
+#include <gudhi/distance_functions.h>
+#include <gudhi/GIC.h>
+
+#include <iostream>
+#include <string>
+#include <vector>
+
+void usage(int nbArgs, char * const progName) {
+  std::cerr << "Error: Number of arguments (" << nbArgs << ") is not correct\n";
+  std::cerr << "Usage: " << progName << " filename.off threshold dim_max [ouput_file.txt]\n";
+  std::cerr << "       i.e.: " << progName << " ../../data/points/alphacomplexdoc.off 60.0\n";
+  exit(-1);  // ----- >>
+}
+
+int main(int argc, char **argv) {
+  if ((argc != 4) && (argc != 5)) usage(argc, (argv[0] - 1));
+
+  std::string off_file_name(argv[1]);
+  double threshold = atof(argv[2]);
+  int dim_max = atoi(argv[3]);
+
+  // Type definitions
+  using Point = std::vector<float>;
+  using Simplex_tree = Gudhi::Simplex_tree<>;
+  using Filtration_value = Simplex_tree::Filtration_value;
+  using Rips_complex = Gudhi::rips_complex::Rips_complex<Filtration_value>;
+  using Graph_t = boost::adjacency_list < boost::vecS, boost::vecS, boost::undirectedS,\
+                                          boost::property < vertex_filtration_t, Filtration_value >,\
+                                          boost::property < edge_filtration_t, Filtration_value > >;
+  using Cover = std::map<int,int>;
+
+  // ----------------------------------------------------------------------------
+  // Init of a graph induced complex from an OFF file
+  // ----------------------------------------------------------------------------
+  Gudhi::Points_off_reader<Point> off_reader(off_file_name);
+  Rips_complex rips_complex_from_points(off_reader.get_point_cloud(), threshold, Euclidean_distance());
+  Simplex_tree st;
+  rips_complex_from_points.create_complex(st, 1);
+  Cover C;
+  Gudhi::graph_induced_complex::Graph_induced_complex GIC(st,C,dim_max);
+  Simplex_tree stree;
+  GIC.create_complex(stree);
+
+
+  std::streambuf* streambufffer;
+  std::ofstream ouput_file_stream;
+
+  if (argc == 5) {
+    ouput_file_stream.open(std::string(argv[4]));
+    streambufffer = ouput_file_stream.rdbuf();
+  } else {
+    streambufffer = std::cout.rdbuf();
+  }
+
+  std::ostream output_stream(streambufffer);
+
+  // ----------------------------------------------------------------------------
+  // Display information about the graph induced complex
+  // ----------------------------------------------------------------------------
+  output_stream << "Graph induced complex is of dimension " << stree.dimension() <<
+                   " - " << stree.num_simplices() << " simplices - " <<
+                   stree.num_vertices() << " vertices." << std::endl;
+
+  output_stream << "Iterator on graph induced complex simplices in the filtration order, with [filtration value]:" <<
+                   std::endl;
+  for (auto f_simplex : stree.filtration_simplex_range()) {
+    output_stream << "   ( ";
+    for (auto vertex : stree.simplex_vertex_range(f_simplex)) {
+      output_stream << vertex << " ";
+    }
+    output_stream << ") -> " << "[" << stree.filtration(f_simplex) << "] ";
+    output_stream << std::endl;
+  }
+
+  ouput_file_stream.close();
+
+  return 0;
+}