message: Check if birth <= death
diff: #define READER_UTILS_H_
  #include <gudhi/graph_simplicial_complex.h>
  +#include <gudhi/Debug_utils.h>
  #include <boost/graph/adjacency_list.hpp>
  @@ -321,6 +322,7 @@ void read_persistence_diagram_from_file(std::string const& filename, OutputItera
  if (n >= 2) {
  //int field = (n == 4 ? static_cast<int>(numbers[0]) : -1);
  int dim = (n >= 3 ? static_cast<int>(numbers[n - 3]) : -1);
  + GUDHI_CHECK(numbers[n - 2] <= numbers[n - 1], "Error: birth > death.");
  *out++ = std::make_tuple(dim, numbers[n - 2], numbers[n - 1]);
  }
  }
  @@ -353,6 +355,7 @@ std::map<int, std::vector<std::pair<double, double>>> read_persistence_diagram_f
  int n = sscanf(line.c_str(), "%lf %lf %lf %lf", &numbers[0], &numbers[1], &numbers[2], &numbers[3]);
  if (n >= 2) {
  int dim = (n >= 3 ? static_cast<int>(numbers[n - 3]) : -1);
  + GUDHI_CHECK(numbers[n - 2] <= numbers[n - 1], "Error: birth > death.");
  ret[dim].push_back(std::make_pair(numbers[n - 2], numbers[n - 1]));
  }
  }
  @@ -391,9 +394,12 @@ std::vector<std::pair<double, double>> read_persistence_diagram_from_file(std::s
  int n = sscanf(line.c_str(), "%lf %lf %lf %lf", &numbers[0], &numbers[1], &numbers[2], &numbers[3]);
  int dim = (n >= 3 ? static_cast<int>(numbers[n - 3]) : -1);
  if (n >= 2 && (only_this_dim == -1 || dim == only_this_dim))
  + {
  + GUDHI_CHECK(numbers[n - 2] <= numbers[n - 1], "Error: birth > death.");
  ret.push_back(std::make_pair(numbers[n - 2], numbers[n - 1]));
  }
  }
  + }
  return ret;
  } // read_persistence_diagram_from_file
  