head.py 文件源码

def _loss(loss_unweighted, weight, name):
  """Returns loss."""
  if weight is None:
    loss = math_ops.reduce_mean(loss_unweighted, name=name)
    return loss, loss
  else:
    loss_weighted = _weighted_loss(loss_unweighted, weight)
    weighted_average_loss = math_ops.div(
        math_ops.reduce_sum(loss_weighted),
        math_ops.to_float(math_ops.reduce_sum(weight)),
        name="weighted_average_loss")
    loss = math_ops.reduce_mean(loss_weighted, name=name)
    return loss, weighted_average_loss