Document utilies in README files using Markdown + move/rename some utilities

Only missing doc for now: Garland_heckbert

git-svn-id: svn+ssh://scm.gforge.inria.fr/svnroot/gudhi/branches/add_utils_in_gudhi_v2@2752 636b058d-ea47-450e-bf9e-a15bfbe3eedb

Former-commit-id: 7ba0113762b6622130835dc9e372acfae29c2db8

1 files changed, 125 insertions, 0 deletions

diff --git a/src/Alpha_complex/utilities/alpha_complex_persistence.cpp b/src/Alpha_complex/utilities/alpha_complex_persistence.cpp
new file mode 100644
index 00000000..9e84e91f
--- /dev/null
+++ b/src/Alpha_complex/utilities/alpha_complex_persistence.cpp
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+#include <boost/program_options.hpp>
+
+#include <CGAL/Epick_d.h>
+
+#include <gudhi/Alpha_complex.h>
+#include <gudhi/Persistent_cohomology.h>
+// to construct a simplex_tree from alpha complex
+#include <gudhi/Simplex_tree.h>
+
+#include <iostream>
+#include <string>
+#include <limits>  // for numeric_limits
+
+using Simplex_tree = Gudhi::Simplex_tree<>;
+using Filtration_value = Simplex_tree::Filtration_value;
+
+void program_options(int argc, char * argv[]
+                     , std::string & off_file_points
+                     , std::string & output_file_diag
+                     , Filtration_value & alpha_square_max_value
+                     , int & coeff_field_characteristic
+                     , Filtration_value & min_persistence);
+
+int main(int argc, char **argv) {
+  std::string off_file_points;
+  std::string output_file_diag;
+  Filtration_value alpha_square_max_value;
+  int coeff_field_characteristic;
+  Filtration_value min_persistence;
+
+  program_options(argc, argv, off_file_points, output_file_diag, alpha_square_max_value,
+                  coeff_field_characteristic, min_persistence);
+
+  // ----------------------------------------------------------------------------
+  // Init of an alpha complex from an OFF file
+  // ----------------------------------------------------------------------------
+  using Kernel = CGAL::Epick_d< CGAL::Dynamic_dimension_tag >;
+  Gudhi::alpha_complex::Alpha_complex<Kernel> alpha_complex_from_file(off_file_points);
+
+  Simplex_tree simplex;
+  if (alpha_complex_from_file.create_complex(simplex, alpha_square_max_value)) {
+    // ----------------------------------------------------------------------------
+    // Display information about the alpha complex
+    // ----------------------------------------------------------------------------
+    std::cout << "Simplicial complex is of dimension " << simplex.dimension() <<
+        " - " << simplex.num_simplices() << " simplices - " <<
+        simplex.num_vertices() << " vertices." << std::endl;
+
+    // Sort the simplices in the order of the filtration
+    simplex.initialize_filtration();
+
+    std::cout << "Simplex_tree dim: " << simplex.dimension() << std::endl;
+    // Compute the persistence diagram of the complex
+    Gudhi::persistent_cohomology::Persistent_cohomology< Simplex_tree,
+        Gudhi::persistent_cohomology::Field_Zp > pcoh(simplex);
+    // initializes the coefficient field for homology
+    pcoh.init_coefficients(coeff_field_characteristic);
+
+    pcoh.compute_persistent_cohomology(min_persistence);
+
+    // Output the diagram in filediag
+    if (output_file_diag.empty()) {
+      pcoh.output_diagram();
+    } else {
+      std::cout << "Result in file: " << output_file_diag << std::endl;
+      std::ofstream out(output_file_diag);
+      pcoh.output_diagram(out);
+      out.close();
+    }
+  }
+
+  return 0;
+}
+
+void program_options(int argc, char * argv[]
+                     , std::string & off_file_points
+                     , std::string & output_file_diag
+                     , Filtration_value & alpha_square_max_value
+                     , int & coeff_field_characteristic
+                     , Filtration_value & min_persistence) {
+  namespace po = boost::program_options;
+  po::options_description hidden("Hidden options");
+  hidden.add_options()
+      ("input-file", po::value<std::string>(&off_file_points),
+       "Name of file containing a point set. Format is one point per line:   X1 ... Xd ");
+
+  po::options_description visible("Allowed options", 100);
+  visible.add_options()
+      ("help,h", "produce help message")
+      ("output-file,o", po::value<std::string>(&output_file_diag)->default_value(std::string()),
+       "Name of file in which the persistence diagram is written. Default print in std::cout")
+      ("max-alpha-square-value,r",
+      po::value<Filtration_value>(&alpha_square_max_value)->default_value(std::numeric_limits<Filtration_value>::infinity()),
+       "Maximal alpha square value for the Alpha complex construction.")
+      ("field-charac,p", po::value<int>(&coeff_field_characteristic)->default_value(11),
+       "Characteristic p of the coefficient field Z/pZ for computing homology.")
+      ("min-persistence,m", po::value<Filtration_value>(&min_persistence),
+       "Minimal lifetime of homology feature to be recorded. Default is 0. Enter a negative value to see zero length intervals");
+
+  po::positional_options_description pos;
+  pos.add("input-file", 1);
+
+  po::options_description all;
+  all.add(visible).add(hidden);
+
+  po::variables_map vm;
+  po::store(po::command_line_parser(argc, argv).
+            options(all).positional(pos).run(), vm);
+  po::notify(vm);
+
+  if (vm.count("help") || !vm.count("input-file")) {
+    std::cout << std::endl;
+    std::cout << "Compute the persistent homology with coefficient field Z/pZ \n";
+    std::cout << "of an Alpha complex defined on a set of input points.\n \n";
+    std::cout << "The output diagram contains one bar per line, written with the convention: \n";
+    std::cout << "   p   dim b d \n";
+    std::cout << "where dim is the dimension of the homological feature,\n";
+    std::cout << "b and d are respectively the birth and death of the feature and \n";
+    std::cout << "p is the characteristic of the field Z/pZ used for homology coefficients." << std::endl << std::endl;
+
+    std::cout << "Usage: " << argv[0] << " [options] input-file" << std::endl << std::endl;
+    std::cout << visible << std::endl;
+    std::abort();
+  }
+}