def backward_cell(self):
"""RNN cell for the backward RNN."""
with tf.compat.v1.variable_scope("backward_cell") as scope:
cell = graph_utils.create_multilayer_cell(self.rnn_cell, scope,
self.dim, self.num_layers, self.input_keep, self.output_keep,
variational_recurrent=self.variational_recurrent_dropout)
return cell
def char_channel_embeddings(self, channel_inputs):
"""
Generate token representations by character composition.
:param channel_inputs: batch input char indices
[[batch, token_size], [batch, token_size], ...]
:return: embeddings_char [source_vocab_size, char_channel_dim]
"""
inputs = [tf.squeeze(x, 1) for x in tf.split(axis=1,
num_or_size_splits=self.max_source_token_size,
value=tf.concat(axis=0, values=channel_inputs))]
input_embeddings = [tf.nn.embedding_lookup(params=self.char_embeddings(), ids=input)
for input in inputs]
if self.sc_char_composition == 'rnn':
with tf.compat.v1.variable_scope("encoder_char_rnn",
reuse=self.char_rnn_vars) as scope:
cell = graph_utils.create_multilayer_cell(
self.sc_char_rnn_cell, scope,
self.sc_char_dim, self.sc_char_rnn_num_layers,
variational_recurrent=self.variational_recurrent_dropout)
rnn_outputs, rnn_states = graph_utils.RNNModel(cell, input_embeddings,
dtype=tf.float32)
self.char_rnn_vars = True
else:
raise NotImplementedError
return [tf.squeeze(x, 0) for x in
tf.split(axis=0, num_or_size_splits=len(channel_inputs),
value=tf.reshape(rnn_states[-1],
[len(channel_inputs), -1, self.sc_char_dim]))]
def horizontal_cell(self):
"""Cell that controls transition from left sibling to right sibling."""
with tf.compat.v1.variable_scope("horizontal_cell") as scope:
cell = graph_utils.create_multilayer_cell(self.rnn_cell, scope,
self.dim, self.num_layers,
self.tg_input_keep,
self.tg_output_keep)
return cell, scope
def vertical_cell(self):
"""Cell that controls transition from parent to child."""
with tf.compat.v1.variable_scope("vertical_cell") as scope:
cell = graph_utils.create_multilayer_cell(self.rnn_cell, scope,
self.dim, self.num_layers,
self.tg_input_keep,
self.tg_output_keep)
return cell, scope
def decoder_cell(self):
if self.copynet:
input_size = self.dim * 2
else:
input_size = self.dim
with tf.compat.v1.variable_scope(self.scope +
"_decoder_cell") as scope:
cell = graph_utils.create_multilayer_cell(
self.rnn_cell,
scope,
self.dim,
self.num_layers,
self.input_keep,
self.output_keep,
variational_recurrent=self.variational_recurrent_dropout,
input_dim=input_size)
return cell