role.py 文件源码

def add_role(variables, roles):
  r"""Add a role to a given variable.

  Parameters
  ----------
  var : :class:`~tensor.TensorVariable`
      The variable to assign the new role to.
  roles : :subclass:`Role`
      this roles will be concatenated with current roles scope.

  Notes
  -----
  Some roles are subroles of others (e.g. :class:`Weight` is a subrole
  of :class:`Parameter`). This function will not add a role if a more
  specific role has already been added. If you need to replace a role
  with a parent role (e.g. replace :class:`Weight` with
  :class:`Parameter`) you must do so manually.

  """
  if roles is None:
    return variables
  roles = tuple([name_to_roles(r) for r in as_tuple(roles)])
  # create tag attribute for variable
  for var in as_tuple(variables):
    # append roles scope
    var_roles = get_roles(var, return_string=False) + \
        roles + \
        get_current_role_scope()
    # ====== handle string roles first ====== #
    _ = []
    for r in var_roles:
      if isinstance(r, string_types):
        _add_to_collection_no_duplication(r, var)
      elif isinstance(r, type) and issubclass(r, Role):
        _.append(r)
    var_roles = _
    # ====== shrink the roles so there is NO subrole ====== #
    new_roles = []
    for r in var_roles:
      if any(r != r0 and issubclass(r0, r) for r0 in var_roles):
        tf.get_collection_ref(r.__name__).remove(var)
      else:
        new_roles.append(r)
    # ====== adding new role ====== #
    for r in new_roles:
      _add_to_collection_no_duplication(r.__name__, var)
  return variables