def _decode(self, z, helper, input_shape, max_length=None):
"""Decodes the given batch of latent vectors vectors, which may be 0-length.
Args:
z: Batch of latent vectors, sized `[batch_size, z_size]`, where `z_size`
may be 0 for unconditioned decoding.
helper: A seq2seq.Helper to use.
input_shape: The shape of each model input vector passed to the decoder.
max_length: (Optional) The maximum iterations to decode.
Returns:
results: The LstmDecodeResults.
"""
initial_state = lstm_utils.initial_cell_state_from_embedding(
self._dec_cell, z, name='decoder/z_to_initial_state')
decoder = lstm_utils.Seq2SeqLstmDecoder(
self._dec_cell,
helper,
initial_state=initial_state,
input_shape=input_shape,
output_layer=self._output_layer)
final_output, final_state, final_lengths = contrib_seq2seq.dynamic_decode(
decoder,
maximum_iterations=max_length,
swap_memory=True,
scope='decoder')
results = lstm_utils.LstmDecodeResults(
rnn_input=final_output.rnn_input[:, :, :self._output_depth],
rnn_output=final_output.rnn_output,
samples=final_output.sample_id,
final_state=final_state,
final_sequence_lengths=final_lengths)
return results
def _testDynamicDecodeRNNWithTrainingHelperMatchesDynamicRNN( # pylint:disable=invalid-name
self, use_sequence_length):
sequence_length = [3, 4, 3, 1, 0]
batch_size = 5
max_time = 8
input_depth = 7
cell_depth = 10
max_out = max(sequence_length)
with self.session(use_gpu=True) as sess:
inputs = np.random.randn(batch_size, max_time,
input_depth).astype(np.float32)
cell = tf.nn.rnn_cell.LSTMCell(cell_depth)
zero_state = cell.zero_state(dtype=tf.float32,
batch_size=batch_size)
helper = seq2seq.TrainingHelper(inputs, sequence_length)
my_decoder = seq2seq.BasicDecoder(cell=cell,
helper=helper,
initial_state=zero_state)
# Match the variable scope of dynamic_rnn below so we end up
# using the same variables
with tf.variable_scope("root") as scope:
final_decoder_outputs, final_decoder_state, _ = seq2seq.dynamic_decode(
my_decoder,
# impute_finished=True ensures outputs and final state
# match those of dynamic_rnn called with sequence_length not None
impute_finished=use_sequence_length,
scope=scope)
with tf.variable_scope(scope, reuse=True) as scope:
final_rnn_outputs, final_rnn_state = tf.nn.dynamic_rnn(
cell,
inputs,
sequence_length=sequence_length
if use_sequence_length else None,
initial_state=zero_state,
scope=scope)
sess.run(tf.global_variables_initializer())
sess_results = sess.run({
"final_decoder_outputs": final_decoder_outputs,
"final_decoder_state": final_decoder_state,
"final_rnn_outputs": final_rnn_outputs,
"final_rnn_state": final_rnn_state
})
# Decoder only runs out to max_out; ensure values are identical
# to dynamic_rnn, which also zeros out outputs and passes along state.
self.assertAllClose(
sess_results["final_decoder_outputs"].rnn_output,
sess_results["final_rnn_outputs"][:, 0:max_out, :])
if use_sequence_length:
self.assertAllClose(sess_results["final_decoder_state"],
sess_results["final_rnn_state"])
def _get_state(self,
inputs,
lengths=None,
initial_state=None):
"""Computes the state of the RNN-NADE (NADE bias parameters and RNN state).
Args:
inputs: A batch of sequences to compute the state from, sized
`[batch_size, max(lengths), num_dims]` or `[batch_size, num_dims]`.
lengths: The length of each sequence, sized `[batch_size]`.
initial_state: An RnnNadeStateTuple, the initial state of the RNN-NADE, or
None if the zero state should be used.
Returns:
final_state: An RnnNadeStateTuple, the final state of the RNN-NADE.
"""
batch_size = int(inputs.shape[0])
if lengths is None:
lengths = tf.tile(tf.shape(inputs)[1:2], [batch_size])
if initial_state is None:
initial_rnn_state = self._get_rnn_zero_state(batch_size)
else:
initial_rnn_state = initial_state.rnn_state
helper = contrib_seq2seq.TrainingHelper(
inputs=inputs, sequence_length=lengths)
decoder = contrib_seq2seq.BasicDecoder(
cell=self._rnn_cell,
helper=helper,
initial_state=initial_rnn_state,
output_layer=self._fc_layer)
final_outputs, final_rnn_state = contrib_seq2seq.dynamic_decode(
decoder)[0:2]
# Flatten time dimension.
final_outputs_flat = magenta.common.flatten_maybe_padded_sequences(
final_outputs.rnn_output, lengths)
b_enc, b_dec = tf.split(
final_outputs_flat, [self._nade.num_hidden, self._nade.num_dims],
axis=1)
return RnnNadeStateTuple(b_enc, b_dec, final_rnn_state)
def _testDynamicDecodeRNN(self, time_major, maximum_iterations=None): # pylint:disable=invalid-name
sequence_length = [3, 4, 3, 1, 0]
batch_size = 5
max_time = 8
input_depth = 7
cell_depth = 10
max_out = max(sequence_length)
with self.session(use_gpu=True) as sess:
if time_major:
inputs = np.random.randn(max_time, batch_size,
input_depth).astype(np.float32)
else:
inputs = np.random.randn(batch_size, max_time,
input_depth).astype(np.float32)
cell = tf.nn.rnn_cell.LSTMCell(cell_depth)
helper = seq2seq.TrainingHelper(inputs,
sequence_length,
time_major=time_major)
my_decoder = seq2seq.BasicDecoder(cell=cell,
helper=helper,
initial_state=cell.zero_state(
dtype=tf.float32,
batch_size=batch_size))
final_outputs, final_state, final_sequence_length = (
seq2seq.dynamic_decode(my_decoder,
output_time_major=time_major,
maximum_iterations=maximum_iterations))
def _t(shape):
if time_major:
return (shape[1], shape[0]) + shape[2:]
return shape
self.assertIsInstance(final_outputs, seq2seq.BasicDecoderOutput)
self.assertIsInstance(final_state, tf.nn.rnn_cell.LSTMStateTuple)
self.assertEqual(
(batch_size, ),
tuple(final_sequence_length.get_shape().as_list()))
self.assertEqual(
_t((batch_size, None, cell_depth)),
tuple(final_outputs.rnn_output.get_shape().as_list()))
self.assertEqual(
_t((batch_size, None)),
tuple(final_outputs.sample_id.get_shape().as_list()))
sess.run(tf.global_variables_initializer())
sess_results = sess.run({
"final_outputs":
final_outputs,
"final_state":
final_state,
"final_sequence_length":
final_sequence_length,
})
# Mostly a smoke test
time_steps = max_out
expected_length = sequence_length
if maximum_iterations is not None:
time_steps = min(max_out, maximum_iterations)
expected_length = [
min(x, maximum_iterations) for x in expected_length
]
self.assertEqual(_t((batch_size, time_steps, cell_depth)),
sess_results["final_outputs"].rnn_output.shape)
self.assertEqual(_t((batch_size, time_steps)),
sess_results["final_outputs"].sample_id.shape)
self.assertCountEqual(expected_length,
sess_results["final_sequence_length"])
