import tensorflow as tf

    """See base class."""
    del shape  # Unused.
    a, b = decode_params[self.A_PARAM_KEY], decode_params[self.B_PARAM_KEY]
    if num_summands is not None:
      shift = b * tf.cast(num_summands, b.dtype)
    else:
      shift = b
    return (encoded_tensors[self.ENCODED_VALUES_KEY] - shift) / a
