loss_ops.py 文件源码

def _safe_mean(losses, num_present):
  """Computes a safe mean of the losses.

  Args:
    losses: A tensor whose elements contain individual loss measurements.
    num_present: The number of measurable losses in the tensor.

  Returns:
    A scalar representing the mean of the losses. If `num_present` is zero,
      then zero is returned.
  """
  total_loss = math_ops.reduce_sum(losses)
  return _safe_div(total_loss, num_present)