'Create an RnnNadeStateTuple of zeros.
Args:
batch_size: batch size.
Returns:
An RnnNadeStateTuple of zeros.'

def zero_state(self, batch_size):

    with tf.name_scope('RnnNadeZeroState', values=[batch_size]):
        zero_state = self._get_rnn_zero_state(batch_size)
        return RnnNadeStateTuple(tf.zeros((batch_size, self._nade.num_hidden), name='b_enc'), tf.zeros((batch_size, self._num_dims), name='b_dec'), zero_state)
