1 files changed, 62 insertions, 0 deletions
diff --git a/example/Alpha_complex/Alpha_complex_from_points.cpp b/example/Alpha_complex/Alpha_complex_from_points.cpp
new file mode 100644
index 00000000..49f77276
--- /dev/null
+++ b/example/Alpha_complex/Alpha_complex_from_points.cpp
@@ -0,0 +1,62 @@
+#include <CGAL/Epick_d.h>
+#include <gudhi/Alpha_complex.h>
+
+#include <iostream>
+#include <string>
+#include <vector>
+#include <limits>  // for numeric limits
+
+typedef CGAL::Epick_d< CGAL::Dimension_tag<2> > Kernel;
+typedef Kernel::Point_d Point;
+typedef std::vector<Point> Vector_of_points;
+
+void usage(int nbArgs, char * const progName) {
+  std::cerr << "Error: Number of arguments (" << nbArgs << ") is not correct\n";
+  std::cerr << "Usage: " << progName << " [alpha_square_max_value]\n";
+  std::cerr << "       i.e.: " << progName << " 60.0\n";
+  exit(-1);  // ----- >>
+}
+
+int main(int argc, char **argv) {
+  if ((argc != 1) && (argc != 2)) usage(argc, (argv[0] - 1));
+
+  // Delaunay complex if alpha_square_max_value is not given by the user.
+  double alpha_square_max_value = std::numeric_limits<double>::infinity();
+  if (argc == 2)
+    alpha_square_max_value = atof(argv[1]);
+
+  // ----------------------------------------------------------------------------
+  // Init of a list of points
+  // ----------------------------------------------------------------------------
+  Vector_of_points points;
+  points.push_back(Point(1.0, 1.0));
+  points.push_back(Point(7.0, 0.0));
+  points.push_back(Point(4.0, 6.0));
+  points.push_back(Point(9.0, 6.0));
+  points.push_back(Point(0.0, 14.0));
+  points.push_back(Point(2.0, 19.0));
+  points.push_back(Point(9.0, 17.0));
+
+  // ----------------------------------------------------------------------------
+  // Init of an alpha complex from the list of points
+  // ----------------------------------------------------------------------------
+  Gudhi::alpha_complex::Alpha_complex<Kernel> alpha_complex_from_points(points, alpha_square_max_value);
+
+  // ----------------------------------------------------------------------------
+  // Display information about the alpha complex
+  // ----------------------------------------------------------------------------
+  std::cout << "Alpha complex is of dimension " << alpha_complex_from_points.dimension() <<
+      " - " << alpha_complex_from_points.num_simplices() << " simplices - " <<
+      alpha_complex_from_points.num_vertices() << " vertices." << std::endl;
+
+  std::cout << "Iterator on alpha complex simplices in the filtration order, with [filtration value]:" << std::endl;
+  for (auto f_simplex : alpha_complex_from_points.filtration_simplex_range()) {
+    std::cout << "   ( ";
+    for (auto vertex : alpha_complex_from_points.simplex_vertex_range(f_simplex)) {
+      std::cout << vertex << " ";
+    }
+    std::cout << ") -> " << "[" << alpha_complex_from_points.filtration(f_simplex) << "] ";
+    std::cout << std::endl;
+  }
+  return 0;
+}