1 files changed, 55 insertions, 0 deletions
diff --git a/src/Persistent_cohomology/example/alpha_complex_persistence.cpp b/src/Persistent_cohomology/example/alpha_complex_persistence.cpp
new file mode 100644
index 00000000..fbadf673
--- /dev/null
+++ b/src/Persistent_cohomology/example/alpha_complex_persistence.cpp
@@ -0,0 +1,55 @@
+#include <iostream>
+#include <string>
+
+// to construct a Delaunay_triangulation from a OFF file
+#include <gudhi/Delaunay_triangulation_off_io.h>
+#include <gudhi/Alpha_complex.h>
+#include <gudhi/Persistent_cohomology.h>
+
+void usage(char * const progName) {
+  std::cerr << "Usage: " << progName << " filename.off alpha_square_max_value[double] " <<
+      "coeff_field_characteristic[integer > 0] min_persistence[double >= -1.0]" << std::endl;
+  std::cerr << "       i.e.: " << progName << " ../../data/points/alphacomplexdoc.off 60.0 2 0.02" << std::endl;
+  exit(-1); // ----- >>
+}
+
+int main(int argc, char **argv) {
+  if (argc != 5) {
+    std::cerr << "Error: Number of arguments (" << argc << ") is not correct" << std::endl;
+    usage(argv[0]);
+  }
+
+  std::string off_file_name(argv[1]);
+  double alpha_square_max_value = atof(argv[2]);
+  int coeff_field_characteristic = atoi(argv[3]);
+  double min_persistence = atof(argv[4]);
+  
+  // ----------------------------------------------------------------------------
+  // Init of an alpha complex from an OFF file
+  // ----------------------------------------------------------------------------
+  typedef CGAL::Epick_d< CGAL::Dynamic_dimension_tag > Kernel;
+  Gudhi::alphacomplex::Alpha_complex<Kernel> alpha_complex_from_file(off_file_name, alpha_square_max_value);
+
+  // ----------------------------------------------------------------------------
+  // Display information about the alpha complex
+  // ----------------------------------------------------------------------------
+  std::cout << "Alpha complex is of dimension " << alpha_complex_from_file.dimension() <<
+      " - " << alpha_complex_from_file.num_simplices() << " simplices - " <<
+      alpha_complex_from_file.num_vertices() << " vertices." << std::endl;
+
+  // Sort the simplices in the order of the filtration
+  alpha_complex_from_file.initialize_filtration();
+
+  std::cout << "Simplex_tree dim: " << alpha_complex_from_file.dimension() << std::endl;
+  // Compute the persistence diagram of the complex
+  Gudhi::persistent_cohomology::Persistent_cohomology< Gudhi::alphacomplex::Alpha_complex<Kernel>,
+      Gudhi::persistent_cohomology::Field_Zp > pcoh(alpha_complex_from_file);
+  // initializes the coefficient field for homology
+  pcoh.init_coefficients(coeff_field_characteristic);
+
+  pcoh.compute_persistent_cohomology(min_persistence);
+
+  pcoh.output_diagram();
+
+  return 0;
+}