head.py 文件源码

def _loss(loss_unweighted, weight, name):
  """Returns a tuple of (loss, weighted_average_loss)."""
  with ops.name_scope(name, values=(loss_unweighted, weight)) as name_scope:
    if weight is None:
      loss = math_ops.reduce_mean(loss_unweighted, name=name_scope)
      return loss, loss
    loss_weighted = _weighted_loss(loss_unweighted, weight)
    # TODO(ptucker): This might be wrong if weights are broadcast to loss shape.
    # We should use tf.losses here.
    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_scope)
    return loss, weighted_average_loss