def __create_navigator(self, main_root):
		navigator_dir = os.path.join(main_root, 'navigator')
		safe_mkdir(navigator_dir)

		navigators = self.__config_mgr.navigator()
		self.__navigator_mgr.create_navigators(navigators, navigator_dir)
def _acc_grads(g_sum, g_w, g):
  """Accumulate gradients in g, weighted by g_w."""
  return [g_sum_i + g_w * g_i for g_sum_i, g_i in zip(g_sum, g)]