tf.contrib.rnn.TimeFreqLSTMCell.zero_state(batch_size, dtype)
Return zero-filled state tensor(s).
Args:
batch_size: int, float, or unit Tensor representing the batch size.
dtype: the data type to use for the state.
Returns:
If state_size is an int or TensorShape, then the return value is a N-D tensor of shape [batch_size x state_size] filled with zeros.
If state_size is a nested list or tuple, then the return value is a nested list or tuple (of the same structure) of 2-D tensors with the s