message: Fix doc and shorten code
diff: @@ -297,15 +297,14 @@ std::vector< std::vector< Filtration_value > > read_lower_triangular_matrix_from
  /**
  Reads a file containing persistance intervals.
  -Each line might contain 2, 3 or 4 values: [field] [dimension] birth death
  +Each line might contain 2, 3 or 4 values: [[field] dimension] birth death
  The output iterator `out` is used this way: `*out++ = std::make_tuple(dim, birth, death);`
  where `dim` is an `int`, `birth` a `double`, and `death` a `double`.
  **/
  template <typename OutputIterator>
  void read_persistence_diagram_from_file(std::string const& filename, OutputIterator out) {
  - std::ifstream in;
  - in.open(filename);
  + std::ifstream in(filename);
  if (!in.is_open()) {
  #ifdef DEBUG_TRACES
  std::cerr << "File \"" << filename << "\" does not exist.\n";
  @@ -326,13 +325,11 @@ void read_persistence_diagram_from_file(std::string const& filename, OutputItera
  }
  }
  }
  -
  - in.close();
  } // read_persistence_diagram_from_file
  /**
  Reads a file containing persistance intervals.
  -Each line might contain 2, 3 or 4 values: [field] [dimension] birth death
  +Each line might contain 2, 3 or 4 values: [[field] dimension] birth death
  The return value is an `std::map[dim, std::vector[std::pair[birth, death]]]`
  where `dim` is an `int`, `birth` a `double`, and `death` a `double`.
  **/
  @@ -340,8 +337,7 @@ std::map<int, std::vector<std::pair<double, double>>> read_persistence_diagram_f
  std::map<int, std::vector<std::pair<double, double>>> ret;
  - std::ifstream in;
  - in.open(filename);
  + std::ifstream in(filename);
  if (!in.is_open()) {
  #ifdef DEBUG_TRACES
  std::cerr << "File \"" << filename << "\" does not exist.\n";
  @@ -362,14 +358,13 @@ std::map<int, std::vector<std::pair<double, double>>> read_persistence_diagram_f
  }
  }
  - in.close();
  return ret;
  } // read_persistence_diagram_from_file
  /**
  Reads a file containing persistance intervals.
  -Each line might contain 2, 3 or 4 values: [field] [dimension] birth death
  +Each line might contain 2, 3 or 4 values: [[field] dimension] birth death
  If `only_this_dim` = -1, dimension is ignored and all lines are returned.
  If `only_this_dim` is >= 0, only the lines where dimension = `only_this_dim`
  (or where dimension is not specified) are returned.
  @@ -380,8 +375,7 @@ std::vector<std::pair<double, double>> read_persistence_diagram_from_file(std::s
  std::vector<std::pair<double, double>> ret;
  - std::ifstream in;
  - in.open(filename);
  + std::ifstream in(filename);
  if (!in.is_open()) {
  #ifdef DEBUG_TRACES
  std::cerr << "File \"" << filename << "\" does not exist.\n";
  @@ -401,7 +395,6 @@ std::vector<std::pair<double, double>> read_persistence_diagram_from_file(std::s
  }
  }
  - in.close();
  return ret;
  } // read_persistence_diagram_from_file
  