message: Formally deprecates nadamoptimizer as it's broken on XLA.
diff: @@ -24,14 +24,37 @@ from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import state_ops
  from tensorflow.python.training import adam
  from tensorflow.python.training import training_ops
  +from tensorflow.python.util import deprecation
  class NadamOptimizer(adam.AdamOptimizer):
  """Optimizer that implements the Nadam algorithm.
  See [Dozat, T., 2015](http://cs229.stanford.edu/proj2015/054_report.pdf).
  +
  + WARNING: due to a known issue this optimizer does not use nesterov momentum
  + on TPUs or when using XLA in general. This is deprecated; instead prefer
  + tf.keras.optimizers.Nadam which does the right thing.
  """
  + @deprecation.deprecated(
  + None, "WARNING: wrong behavior with XLA. Use tf.keras.optimizers.Nadam.")
  + def __init__(
  + self,
  + learning_rate=0.001,
  + beta1=0.9,
  + beta2=0.999,
  + epsilon=1e-08,
  + use_locking=False,
  + name="Adam"):
  + super(NadamOptimizer, self).__init__(
  + learning_rate=learning_rate,
  + beta1=beta1,
  + beta2=beta2,
  + epsilon=epsilon,
  + use_locking=use_locking,
  + name=name)
  +
  def _apply_dense(self, grad, var):
  m = self.get_slot(var, "m")
  v = self.get_slot(var, "v")
  