return_state=True,
dropout=0.4,
recurrent_dropout=0.2)
decoder_outputs, decoder_fwd_state, decoder_back_state = decoder_lstm(
dec_emb, initial_state=[state_h, state_c])
# Attention layer
attn_layer = AttentionLayer(name='attention_layer')
attn_out, attn_states = attn_layer([encoder_outputs, decoder_outputs])
# Concat attention input and decoder LSTM output
decoder_concat_input = Concatenate(
axis=-1, name='concat_layer')([decoder_outputs, attn_out])
#dense layer
decoder_dense = TimeDistributed(Dense(y_voc, activation='softmax'))
decoder_outputs = decoder_dense(decoder_concat_input)
# Define the model
model = Model([encoder_inputs, decoder_inputs], decoder_outputs)
model.summary()
model.compile(optimizer='rmsprop', loss='sparse_categorical_crossentropy')
es = EarlyStopping(monitor='val_loss', mode='min', verbose=1, patience=2)
#Wait for the epochs to get over
history = model.fit([x_tr, y_tr[:, :-1]],
y_tr.reshape(y_tr.shape[0], y_tr.shape[1], 1)[:, 1:],
epochs=50,
def _create_decoder(cells,
batch_size,
encoder_outputs,
encoder_state,
encoder_lengths,
decoding_inputs,
decoding_lengths,
embed_matrix,
target_vocab_size,
scope,
max_sequence_size,
use_attention=True,
softmax_temperature=None):
"""Summary
Parameters
----------
cells : TYPE
Description
batch_size : TYPE
Description
encoder_outputs : TYPE
Description
encoder_state : TYPE
Description
encoder_lengths : TYPE
Description
decoding_inputs : TYPE
Description
decoding_lengths : TYPE
Description
embed_matrix : TYPE
Description
target_vocab_size : TYPE
Description
scope : TYPE
Description
max_sequence_size : TYPE
Description
use_attention : bool, optional
Description
softmax_temperature : float32, optional
Values above 1.0 result in more random samples
Returns
-------
TYPE
Description
"""
from tensorflow.python.layers.core import Dense
# Output projection
output_layer = Dense(target_vocab_size, name='output_projection')
# Setup Attention
if use_attention:
attn_mech = tf.contrib.seq2seq.LuongAttention(
cells.output_size, encoder_outputs, encoder_lengths, scale=True)
cells = tf.contrib.seq2seq.AttentionWrapper(
cell=cells,
attention_mechanism=attn_mech,
attention_layer_size=cells.output_size,
alignment_history=False)
initial_state = cells.zero_state(
dtype=tf.float32, batch_size=batch_size)
initial_state = initial_state.clone(cell_state=encoder_state)
# Setup training a build decoder
helper = tf.contrib.seq2seq.TrainingHelper(
inputs=decoding_inputs,
sequence_length=decoding_lengths,
time_major=False)
train_decoder = tf.contrib.seq2seq.BasicDecoder(
cell=cells,
helper=helper,
initial_state=initial_state,
output_layer=output_layer)
train_outputs, _, _ = tf.contrib.seq2seq.dynamic_decode(
train_decoder,
output_time_major=False,
impute_finished=True,
maximum_iterations=max_sequence_size)
train_logits = tf.identity(train_outputs.rnn_output, name='train_logits')
# Setup inference and build decoder
scope.reuse_variables()
start_tokens = tf.tile(tf.constant([GO_ID], dtype=tf.int32), [batch_size])
helper = tf.contrib.seq2seq.SampleEmbeddingHelper(
embedding=embed_matrix, start_tokens=start_tokens, end_token=EOS_ID, softmax_temperature=softmax_temperature)
# helper = tf.contrib.seq2seq.GreedyEmbeddingHelper(
# embedding=embed_matrix, start_tokens=start_tokens, end_token=EOS_ID)
infer_decoder = tf.contrib.seq2seq.BasicDecoder(
cell=cells,
helper=helper,
initial_state=initial_state,
output_layer=output_layer)
infer_outputs, _, _ = tf.contrib.seq2seq.dynamic_decode(
infer_decoder,
output_time_major=False,
impute_finished=True,
maximum_iterations=max_sequence_size)
infer_logits = tf.identity(infer_outputs.sample_id, name='infer_logits')
return train_logits, infer_logits
embedding_layer = build_embedding(words_class, 130)
embedding_layer_chi = build_embedding(150, 130, name='chi') # 解码词语嵌入
# lstm 输入
lstm_inputs = tf.nn.embedding_lookup(embedding_layer, inputs)
# 编码层
encoder_layer = build_lstm(lstm_hidden_num, 0.9, 1)
# 初始化lstm 层
initial_state = encoder_layer.zero_state(batch_size, tf.float32)
# lstm 动态时间维度展开
encoder_lstm_outputs, encoder_final_state = tf.nn.dynamic_rnn(
encoder_layer, lstm_inputs, dtype=tf.float32)
# 开始构建解码层
# 解码层第一个传入的字符为`<BOE>`
encoder_final_c = encoder_final_state[0][0] # 编码层最后的状态 c
# 全连接层
F_C_layer = Dense(fully_connect)
#decoder_lstm_inputs = tf.nn.embedding_lookup(embedding_layer_chi, decoder_inputs)
#decoder_layer = build_lstm(lstm_hidden_num, 0.9, 1)
#decoder_layer = tf.contrib.rnn.LSTMCell(100)
#decoder_lstm_outputs, decoder_final_state = tf.nn.dynamic_rnn(decoder_layer, decoder_lstm_inputs, initial_state=\
# encoder_final_state, scope="plain_decoder")# 坑啊，两个dynamic 要用scope进行区分
#decoder_lstm_outputs, decoder_final_state = inference_layer(decoder_inputs, encoder_final_state, is_inference=False)
# 构建损失函数
#decoder_logits = tf.to_float(decoder_logits, name='ToFloat32')
# 解码层构建-for inference
def inference_layer(inputs_infer, initial_state=None, is_inference=True):
"""
def atten_decoder_input_fn(inputs, attention):
_input_layer = Dense(self.state_size * 2)
return _input_layer(tf.concat([inputs, attention], 1))
def create_model(self):
self.encoder_input = tf.placeholder(tf.int32, [None, None],
name='encoder_input')
self.encoder_input_lengths = tf.placeholder(
tf.int32, [None], name='encoder_input_lengths')
self.dropout_kp = tf.placeholder(tf.float32, name='dropout_kp')
# GO
self.decoder_input = tf.placeholder(tf.int32, [None, None],
name='decoder_input')
# EOS
self.decoder_target = tf.placeholder(tf.int32, [None, None],
name='decoder_target')
self.decoder_input_lengths = tf.placeholder(
tf.int32, [None], name='decoder_input_lengths')
self.max_decoder_sequence_length = tf.reduce_max(
self.decoder_input_lengths, name='max_decoder_sequence_length')
self.max_encoder_sequence_length = tf.reduce_max(
self.encoder_input_lengths, name='max_encoder_sequence_length')
self.topic_words = tf.placeholder(tf.int32, [None, None],
name='topic_words')
with tf.device('/cpu:0'), tf.name_scope('embedding'):
W = tf.Variable(tf.constant(
0., shape=[self.vocab_size, self.embedding_size]),
name="W")
self.embedding_placeholder = tf.placeholder(
tf.float32, [self.vocab_size, self.embedding_size],
name='embedding_placeholder')
embeding_init = W.assign(self.embedding_placeholder)
encoder_embedded_inputs = tf.nn.embedding_lookup(
embeding_init, self.encoder_input)
decoder_embedded_input = tf.nn.embedding_lookup(
embeding_init, self.decoder_input)
topic_words_embedded = tf.nn.embedding_lookup(
embeding_init, self.topic_words)
with tf.variable_scope('content_encoder'):
fw_encoder_cells = []
for _ in range(self.num_layers):
cell = tf.contrib.rnn.GRUCell(self.embedding_size)
fw_encoder_wraped_cell = tf.contrib.rnn.DropoutWrapper(
cell, output_keep_prob=self.dropout_kp)
fw_encoder_cells.append(fw_encoder_wraped_cell)
fw_encoder_cell = tf.contrib.rnn.MultiRNNCell(fw_encoder_cells)
bw_encoder_cells = []
for _ in range(self.num_layers):
cell = tf.contrib.rnn.GRUCell(self.embedding_size)
bw_encoder_wraped_cell = tf.contrib.rnn.DropoutWrapper(
cell, output_keep_prob=self.dropout_kp)
bw_encoder_cells.append(bw_encoder_wraped_cell)
bw_encoder_cell = tf.contrib.rnn.MultiRNNCell(bw_encoder_cells)
((content_output_fw, content_output_bw),
(content_output_state_fw, content_output_state_bw)) = \
tf.nn.bidirectional_dynamic_rnn(cell_fw=fw_encoder_cell,
cell_bw=bw_encoder_cell,
inputs=encoder_embedded_inputs, dtype=tf.float32)
content_outputs = tf.concat([content_output_fw, content_output_bw],
axis=-1)
content_state = tf.squeeze(tf.concat(
[content_output_state_fw, content_output_state_bw], axis=-1),
axis=0)
with tf.variable_scope('topic_encoder'):
topic_fw_encoder_cells = []
for _ in range(self.num_layers):
cell = tf.contrib.rnn.GRUCell(self.embedding_size)
topic_fw_encoder_wraped_cell = tf.contrib.rnn.DropoutWrapper(
cell, output_keep_prob=self.dropout_kp)
topic_fw_encoder_cells.append(topic_fw_encoder_wraped_cell)
topic_fw_encoder_cell = tf.contrib.rnn.MultiRNNCell(
topic_fw_encoder_cells)
topic_bw_encoder_cells = []
for _ in range(self.num_layers):
cell = tf.contrib.rnn.GRUCell(self.embedding_size)
topic_bw_encoder_wraped_cell = tf.contrib.rnn.DropoutWrapper(
cell, output_keep_prob=self.dropout_kp)
topic_bw_encoder_cells.append(topic_bw_encoder_wraped_cell)
topic_bw_encoder_cell = tf.contrib.rnn.MultiRNNCell(
topic_bw_encoder_cells)
# num_topic_words = tf.tile(tf.constant([self.K], dtype=tf.int32), [tf.shape(self.topic_words)[0]])
((topic_output_fw, topic_output_bw),
(topic_output_state_fw, topic_output_state_bw)) = \
tf.nn.bidirectional_dynamic_rnn(cell_fw=topic_fw_encoder_cell,
cell_bw=topic_bw_encoder_cell,
inputs=topic_words_embedded, dtype=tf.float32)
topic_outputs = tf.concat([topic_output_fw, topic_output_bw],
axis=-1)
with tf.variable_scope("topic_summarizer"):
topic_words_embedded_flatten = tf.reshape(
topic_words_embedded, [-1, self.K * self.embedding_size])
summarizer_W = tf.get_variable(
name='summarizer_W',
shape=[self.K * self.embedding_size, self.summarizer_size],
dtype=tf.float32,
initializer=tf.truncated_normal_initializer(mean=0.0,
stddev=0.1))
summarizer_b = tf.Variable(tf.constant(
0.1, dtype=tf.float32, shape=[self.summarizer_size]),
name='summarizer_b')
summarizer_vector = tf.tanh(
tf.nn.xw_plus_b(topic_words_embedded_flatten, summarizer_W,
summarizer_b))
with tf.variable_scope('decoder') as decoder:
decoder_cells = []
for _ in range(self.num_layers):
cell = tf.contrib.rnn.GRUCell(self.embedding_size)
decoder_wraped_cell = tf.contrib.rnn.DropoutWrapper(
cell, output_keep_prob=self.dropout_kp)
decoder_cells.append(decoder_wraped_cell)
decoder_cell = tf.contrib.rnn.MultiRNNCell(decoder_cells)
output_layer = Dense(
self.vocab_size,
kernel_initializer=tf.truncated_normal_initializer(mean=0.0,
stddev=0.1),
activation=tf.nn.sigmoid)
state_layer = Dense(
self.embedding_size,
kernel_initializer=tf.truncated_normal_initializer(mean=0.0,
stddev=0.1))
self.decoder_outputs_array = tensor_array_ops.TensorArray(
dtype=tf.float32,
size=self.max_decoder_sequence_length,
dynamic_size=False,
infer_shape=True)
attention_size = 10
def content_score_mlp(hidden_state):
content_score_W_1 = tf.get_variable(
name='content_score_W_1',
shape=[self.embedding_size, attention_size],
dtype=tf.float32,
initializer=tf.truncated_normal_initializer(mean=0.0,
stddev=0.1))
content_score_W_2 = tf.get_variable(
name='content_score_W_2',
shape=[2 * self.embedding_size, attention_size],
dtype=tf.float32,
initializer=tf.truncated_normal_initializer(mean=0.0,
stddev=0.1))
content_score_W_3 = tf.get_variable(
name='content_score_W_3',
shape=[self.summarizer_size, attention_size],
dtype=tf.float32,
initializer=tf.truncated_normal_initializer(mean=0.0,
stddev=0.1))
content_score_v = tf.get_variable(
name='content_score_v',
shape=[attention_size, 1],
dtype=tf.float32,
initializer=tf.truncated_normal_initializer(mean=0.0,
stddev=0.1))
addition = tf.tanh(
tf.matmul(hidden_state, content_score_W_1) +
tf.transpose(tf.tensordot(
content_outputs, content_score_W_2, axes=[[2], [0]]),
perm=[1, 0, 2]) +
tf.matmul(summarizer_vector, content_score_W_3))
addition = tf.transpose(addition, perm=[1, 0, 2])
weight = tf.tensordot(addition,
content_score_v,
axes=[[2], [0]])
return weight
def topic_score_mlp(hidden_state):
topic_score_W_1 = tf.get_variable(
name='topic_score_W_1',
shape=[self.embedding_size, attention_size],
dtype=tf.float32,
initializer=tf.truncated_normal_initializer(mean=0.0,
stddev=0.1))
topic_score_W_2 = tf.get_variable(
name='topic_score_W_2',
shape=[2 * self.embedding_size, attention_size],
dtype=tf.float32,
initializer=tf.truncated_normal_initializer(mean=0.0,
stddev=0.1))
topic_score_W_3 = tf.get_variable(
name='topic_score_W_3',
shape=[2 * self.embedding_size, attention_size],
dtype=tf.float32,
initializer=tf.truncated_normal_initializer(mean=0.0,
stddev=0.1))
topic_score_v = tf.get_variable(
name='topic_score_v',
shape=[attention_size, 1],
dtype=tf.float32,
initializer=tf.truncated_normal_initializer(mean=0.0,
stddev=0.1))
addition = tf.tanh(
tf.matmul(hidden_state, topic_score_W_1) +
tf.transpose(tf.tensordot(
topic_outputs, topic_score_W_2, axes=[[2], [0]]),
perm=[1, 0, 2]) +
tf.matmul(content_outputs[:, -1, :], topic_score_W_3))
addition = tf.transpose(addition, perm=[1, 0, 2])
weight = tf.tensordot(addition, topic_score_v, axes=[[2], [0]])
return weight
decoder_state_size = 300
def get_overall_state(hidden_state):
content_weights = content_score_mlp(hidden_state)
topic_weights = topic_score_mlp(hidden_state)
content_attention_output = tf.reduce_sum(content_outputs *
content_weights,
axis=1)
topic_attention_output = tf.reduce_sum(topic_outputs *
topic_weights,
axis=1)
state_W = tf.get_variable(
name='state_W',
shape=[self.embedding_size, decoder_state_size],
dtype=tf.float32,
initializer=tf.truncated_normal_initializer(mean=0.0,
stddev=0.1))
content_attention_W = tf.get_variable(
name='content_attention_W',
shape=[2 * self.embedding_size, decoder_state_size],
dtype=tf.float32,
initializer=tf.truncated_normal_initializer(mean=0.0,
stddev=0.1))
topic_attention_W = tf.get_variable(
name='topic_attention_W',
shape=[2 * self.embedding_size, decoder_state_size],
dtype=tf.float32,
initializer=tf.truncated_normal_initializer(mean=0.0,
stddev=0.1))
decoder_b = tf.get_variable(
name='decoder_b',
shape=[decoder_state_size],
dtype=tf.float32,
initializer=tf.constant_initializer(0.1))
overall_state = tf.matmul(hidden_state, state_W) + \
tf.matmul(content_attention_output, content_attention_W) + \
tf.matmul(topic_attention_output, topic_attention_W) + \
decoder_b
return overall_state
training_initial_state = state_layer(content_state)
def training_decode(i, hidden_state, decoder_outputs_array):
overall_state = get_overall_state(hidden_state)
cell_outputs, states = decoder_cell(
decoder_embedded_input[:, i, :], (overall_state, ))
outputs = output_layer(cell_outputs)
decoder_outputs_array = decoder_outputs_array.write(i, outputs)
return i + 1, states[0], decoder_outputs_array
_, _, self.decoder_outputs_array = control_flow_ops.while_loop(
cond=lambda i, _1, _2: i < self.max_decoder_sequence_length,
body=training_decode,
loop_vars=(tf.constant(0, dtype=tf.int32),
training_initial_state, self.decoder_outputs_array))
training_decoder_output = tf.transpose(
self.decoder_outputs_array.stack(), perm=[1, 0, 2])
beam_width = 5
with tf.variable_scope(decoder, reuse=True):
def get_final_state(state):
final_state = tensor_array_ops.TensorArray(dtype=tf.float32,
size=beam_width,
dynamic_size=False,
infer_shape=True)
state_array = tf.unstack(state.cell_state[0],
num=beam_width,
axis=1)
for i in range(beam_width):
final_state = final_state.write(
i, get_overall_state(state_array[i]))
final_state = tf.transpose(final_state.stack(), perm=[1, 0, 2])
new_state = tf.contrib.seq2seq.BeamSearchDecoderState(
(final_state, ), state.log_probs, state.finished,
state.lengths)
return new_state
start_tokens = tf.tile(tf.constant([GO_ID], dtype=tf.int32),
[tf.shape(content_state)[0]])
overall_state = get_overall_state(state_layer(content_state))
decoder_initial_state = tf.contrib.seq2seq.tile_batch(
(overall_state, ), multiplier=beam_width)
beam_search_decoder = tf.contrib.seq2seq.BeamSearchDecoder(
cell=decoder_cell,
embedding=embeding_init,
start_tokens=start_tokens,
end_token=EOS_ID,
initial_state=decoder_initial_state,
beam_width=beam_width,
output_layer=output_layer)
predicted_ids = tensor_array_ops.TensorArray(
dtype=tf.int32,
size=self.max_decoder_sequence_length,
dynamic_size=False,
infer_shape=True)
parent_ids = tensor_array_ops.TensorArray(
dtype=tf.int32,
size=self.max_decoder_sequence_length,
dynamic_size=False,
infer_shape=True)
scores = tensor_array_ops.TensorArray(
dtype=tf.float32,
size=self.max_decoder_sequence_length,
dynamic_size=False,
infer_shape=True)
initial_finished, initial_inputs, initial_state = beam_search_decoder.initialize(
)
initial_final_state = get_final_state(initial_state)
initial_sequence_lengths = array_ops.zeros_like(initial_finished,
dtype=tf.int32)
num_decoder_output = tf.identity(self.max_decoder_sequence_length)
def predicting_decode(i, input_data, hidden_state, predicted_ids,
parent_ids, sequence_lengths, finished,
scores):
outputs, next_state, next_inputs, decoder_finished = beam_search_decoder.step(
i, input_data, hidden_state)
next_finished = math_ops.logical_or(decoder_finished, finished)
next_finished = math_ops.logical_or(
next_finished, i + 1 >= num_decoder_output)
next_sequence_lengths = array_ops.where(
math_ops.logical_and(math_ops.logical_not(finished),
next_finished),
array_ops.fill(array_ops.shape(sequence_lengths), i + 1),
sequence_lengths)
states = get_final_state(next_state)
predicted_ids = predicted_ids.write(i, outputs.predicted_ids)
parent_ids = parent_ids.write(i, outputs.parent_ids)
scores = scores.write(i, outputs.scores)
return i + 1, next_inputs, states, predicted_ids, parent_ids, \
next_sequence_lengths, next_finished, scores
_, _next_inputs, _states, predicted_ids, parent_ids, \
sequence_lengths, finished, scores = control_flow_ops.while_loop(
cond=lambda i, _1, _2, _3, _4, _5, _6, _7: i < self.max_decoder_sequence_length,
body=predicting_decode,
loop_vars=(tf.constant(0, dtype=tf.int32), initial_inputs,
initial_final_state, predicted_ids, parent_ids,
initial_sequence_lengths, initial_finished, scores)
)
predicted_ids = predicted_ids.stack()
parent_ids = parent_ids.stack()
scores = scores.stack()
final_outputs_instance = tf.contrib.seq2seq.BeamSearchDecoderOutput(
scores, predicted_ids, parent_ids)
final_outputs, final_state = beam_search_decoder.finalize(
final_outputs_instance, _states, sequence_lengths)
self.training_logits = tf.identity(training_decoder_output,
name='training_logits')
self.predicting_logits = tf.identity(final_outputs.predicted_ids,
name='predicting_logits')
masks = tf.sequence_mask(self.decoder_input_lengths,
self.max_decoder_sequence_length,
dtype=tf.float32,
name='masks')
self.cost = tf.contrib.seq2seq.sequence_loss(self.training_logits,
self.decoder_target,
masks)
optimizer = tf.train.AdamOptimizer(learning_rate=0.00001)
gradients = optimizer.compute_gradients(self.cost)
capped_gradients = [(tf.clip_by_value(grad, -5.0, 5.0), var)
for grad, var in gradients if grad is not None]
self.train_op = optimizer.apply_gradients(capped_gradients)
def build_decoder(self):
with tf.variable_scope("decode"):
for layer in range(self.num_layers):
with tf.variable_scope('decoder_{}'.format(layer + 1)):
dec_cell = tf.contrib.rnn.LayerNormBasicLSTMCell(2 * self.lstm_hidden_units)
dec_cell = tf.contrib.rnn.DropoutWrapper(dec_cell, input_keep_prob=self.keep_prob)
self.output_layer = Dense(self.vocab_size)
self.init_state = dec_cell.zero_state(self.batch_size, tf.float32)
with tf.name_scope("training_decoder"):
training_helper = tf.contrib.seq2seq.TrainingHelper(inputs=self.dec_embed_input,
sequence_length=self.target_sentence_length,
time_major=False)
training_decoder = basic_decoder.BasicDecoder(dec_cell,
training_helper,
initial_state=self.init_state,
latent_vector=self.z_tilda,
output_layer=self.output_layer)
self.training_logits, _state, _len = tf.contrib.seq2seq.dynamic_decode(training_decoder,
output_time_major=False,
impute_finished=True,
maximum_iterations=self.num_tokens)
self.training_logits = tf.identity(self.training_logits.rnn_output, 'logits')
with tf.name_scope("validate_decoder"):
start_token = self.word_index['GO']
end_token = self.word_index['EOS']
start_tokens = tf.tile(tf.constant([start_token], dtype=tf.int32), [self.batch_size],
name='start_tokens')
inference_helper = tf.contrib.seq2seq.GreedyEmbeddingHelper(self.embeddings,
start_tokens,
end_token)
inference_decoder = basic_decoder.BasicDecoder(dec_cell,
inference_helper,
initial_state=self.init_state,
latent_vector=self.z_tilda,
output_layer=self.output_layer)
self.validate_logits, _state, _len = tf.contrib.seq2seq.dynamic_decode(inference_decoder,
output_time_major=False,
impute_finished=True,
maximum_iterations=self.num_tokens)
self.validate_sent = tf.identity(self.validate_logits.sample_id, name='predictions')
with tf.name_scope("inference_decoder"):
start_token = self.word_index['GO']
end_token = self.word_index['EOS']
start_tokens = tf.tile(tf.constant([start_token], dtype=tf.int32), [self.batch_size],
name='start_tokens')
inference_helper = tf.contrib.seq2seq.GreedyEmbeddingHelper(self.embeddings,
start_tokens,
end_token)
inference_decoder = basic_decoder.BasicDecoder(dec_cell,
inference_helper,
initial_state=self.init_state,
latent_vector=self.z_sampled,
output_layer=self.output_layer)
self.inference_logits, _state, _len = tf.contrib.seq2seq.dynamic_decode(inference_decoder,
output_time_major=False,
impute_finished=True,
maximum_iterations=self.num_tokens)
self.inference_logits = tf.identity(self.inference_logits.sample_id, name='predictions')
scope="encoder_rnn")
decoder_inputs = tf.placeholder(tf.int32,
shape=[None, None],
name="decoder_inputs")
decoder_labels = tf.placeholder(tf.int32,
shape=[None, None],
name="decoder_labels")
decoder_lengths = tf.placeholder(tf.int32,
shape=[None],
name="decoder_lengths")
decoder_emb = tf.nn.embedding_lookup(embedding, decoder_inputs)
helper = seq2seq.TrainingHelper(decoder_emb, decoder_lengths)
projection = Dense(embedding.shape[0], use_bias=False)
decoder_cell = GRUCell(encoder_cell.state_size)
decoder = seq2seq.BasicDecoder(decoder_cell,
helper,
encoder_state,
output_layer=projection)
decoder_outputs, _, _ = seq2seq.dynamic_decode(decoder, scope="decoder")
decoder_outputs = decoder_outputs.rnn_output
question_mask = tf.sequence_mask(decoder_lengths, dtype=tf.float32)
question_loss = seq2seq.sequence_loss(logits=decoder_outputs,
targets=decoder_labels,
weights=question_mask,
def attn_decoder_input_fn(inputs, attention):
_input_layer = Dense(num_nodes,
name='attn_input_feeding',
dtype=tf.float32)
return _input_layer(array_ops.concat([inputs, attention], -1))
def _model(self, features, labels, mode, params):
"""
main model.
"""
question_sequence = features['question_seq']
answer_sequence = features['answer_seq']
batch_size = tf.shape(question_sequence)[0]
start_token = tf.ones([1], tf.int32)
model_size = params["model_size"]
num_layers = params["num_layers"]
keep_prob = params["keep_prob"]
vocab_size = params["vocab_size"]
embedding_size = params["embedding_size"]
question_lengths = tf.reduce_sum(
tf.to_int32(tf.not_equal(question_sequence, self.vocabs["<PAD>"])),
1)
answer_lengths = tf.reduce_sum(
tf.to_int32(tf.not_equal(answer_sequence, self.vocabs["<PAD>"])),
1)
question_embed = layers.embed_sequence(question_sequence,
vocab_size=vocab_size,
embed_dim=embedding_size,
scope='embed')
answer_embed = layers.embed_sequence(answer_sequence,
vocab_size=vocab_size,
embed_dim=embedding_size,
scope='embed',
reuse=True)
with tf.variable_scope('embed', reuse=True):
embeddings = tf.get_variable('embeddings')
fcells = []
for i in range(num_layers):
c = tf.nn.rnn_cell.GRUCell(model_size)
c = tf.nn.rnn_cell.DropoutWrapper(c,
input_keep_prob=keep_prob,
output_keep_prob=keep_prob)
fcells.append(c)
# I cant figure out how to use tuple version.
fcell = tf.nn.rnn_cell.MultiRNNCell(fcells)
#bcells = []
#for i in range(num_layers):
# c = tf.nn.rnn_cell.GRUCell(model_size)
# c = tf.nn.rnn_cell.DropoutWrapper(c, input_keep_prob=keep_prob,
# output_keep_prob=keep_prob)
# bcells.append(c)
# I cant figure out how to use tuple version.
#bcell = tf.nn.rnn_cell.MultiRNNCell(bcells)
bcell = tf.contrib.rnn.GRUCell(num_units=model_size)
#icell = tf.contrib.rnn.GRUCell(num_units=model_size)
encoder_outputs, encoder_final_state = tf.nn.bidirectional_dynamic_rnn(
fcell,
bcell,
question_embed,
sequence_length=question_lengths,
dtype=tf.float32)
# helpers
train_helper = tf.contrib.seq2seq.TrainingHelper(answer_embed,
answer_lengths,
time_major=False)
start_tokens = tf.tile(tf.constant([self.vocabs['<START>']],
dtype=tf.int32), [batch_size],
name='start_tokens')
pred_helper = tf.contrib.seq2seq.GreedyEmbeddingHelper(
embeddings,
start_tokens=start_tokens,
end_token=self.vocabs["<EOS>"])
# rnn cell and dense layer
cell = tf.contrib.rnn.GRUCell(num_units=model_size)
cells = []
for i in range(num_layers):
c = tf.nn.rnn_cell.GRUCell(model_size)
c = tf.nn.rnn_cell.DropoutWrapper(c,
input_keep_prob=keep_prob,
output_keep_prob=keep_prob)
cells.append(c)
# I cant figure out how to use tuple version.
cell = tf.nn.rnn_cell.MultiRNNCell(cells)
projection_layer = Dense(
units=vocab_size,
kernel_initializer=tf.truncated_normal_initializer(mean=0.0,
stddev=0.1))
# deocder in seq2seq model. For this case we don't have an encoder.
def decode(helper, scope, output_max_length, reuse=None):
with tf.variable_scope(scope, reuse=reuse):
attention_mechanism = tf.contrib.seq2seq.BahdanauAttention(
num_units=model_size,
memory=encoder_outputs[0],
memory_sequence_length=question_lengths)
#cell = tf.contrib.rnn.GRUCell(num_units=model_size)
attn_cell = tf.contrib.seq2seq.AttentionWrapper(
cell, attention_mechanism, attention_layer_size=model_size)
#out_cell = tf.contrib.rnn.OutputProjectionWrapper(
# attn_cell, vocab_size, reuse=reuse
#)
decoder = tf.contrib.seq2seq.BasicDecoder(
cell=attn_cell,
helper=helper,
initial_state=attn_cell.zero_state(dtype=tf.float32,
batch_size=batch_size),
#initial_state=encoder_final_state,
output_layer=projection_layer)
outputs = tf.contrib.seq2seq.dynamic_decode(
decoder=decoder,
output_time_major=False,
impute_finished=True,
maximum_iterations=output_max_length)
return outputs[0]
train_outputs = decode(train_helper, 'decode', 3000)
pred_outputs = decode(pred_helper, 'decode', 300, reuse=True)
targets = answer_sequence[:, 1:]
probs = tf.nn.softmax(pred_outputs.rnn_output, name="probs")
# in case in prediction mode return
if mode == tf.estimator.ModeKeys.PREDICT:
return tf.estimator.EstimatorSpec(mode=mode,
predictions={
"probs": probs,
"syms":
pred_outputs.sample_id
})
# mask the PADs
mask = tf.to_float(
tf.not_equal(answer_sequence[:, :-1], self.vocabs["<PAD>"]))
#tf.identity(mask[0], name='mask')
#tf.identity(targets[0], name='targets')
#tf.identity(train_outputs.rnn_output[0,output_lengths[0]-2:output_lengths[0],:], name='rnn_out')
# Loss function
loss = tf.contrib.seq2seq.sequence_loss(
train_outputs.rnn_output[:, :-1, :], targets, mask)
tf.summary.scalar("loss", loss)
# Optimizer
learning_rate = tf.Variable(0.0, trainable=False)
initial_learning_rate = tf.constant(0.001)
learning_rate = tf.train.exponential_decay(initial_learning_rate,
tf.train.get_global_step(),
100, 0.99)
tf.summary.scalar("learning_rate", learning_rate)
tvars = tf.trainable_variables()
grads, _ = tf.clip_by_global_norm(tf.gradients(loss, tvars), 5.0)
optimizer = tf.train.AdamOptimizer(learning_rate)
# Visualise gradients
vis_grads = [0 if i is None else i for i in grads]
for g in vis_grads:
tf.summary.histogram("gradients_" + str(g), g)
train_op = optimizer.apply_gradients(
zip(grads, tvars), global_step=tf.train.get_global_step())
tf.identity(question_sequence[0], name="train_input")
tf.identity(train_outputs.sample_id[0], name='train_pred')
tf.identity(pred_outputs.sample_id[0], name='predictions')
return tf.estimator.EstimatorSpec(mode=mode,
predictions=None,
loss=loss,
train_op=train_op)
def __init__(self,
rnn_size=128,
layer_size=2,
encoder_vocab_size,
decoder_vocab_size,
embedding_dim=200,
grad_clip=5,
is_inference=False):
# define inputs
self.input_x = tf.placeholder(tf.int32,
shape=[None, None],
name='input_ids')
# define embedding layer
with tf.variable_scope('embedding'):
encoder_embedding = tf.Variable(tf.truncated_normal(
shape=[encoder_vocab_size, embedding_dim], stddev=0.1),
name='encoder_embedding')
decoder_embedding = tf.Variable(tf.truncated_normal(
shape=[decoder_vocab_size, embedding_dim], stddev=0.1),
name='decoder_embedding')
# define encoder
with tf.variable_scope('encoder'):
encoder = self._get_simple_lstm(rnn_size, layer_size)
with tf.device('/cpu:0'):
input_x_embedded = tf.nn.embedding_lookup(encoder_embedding,
self.input_x)
encoder_outputs, encoder_state = tf.nn.dynamic_rnn(encoder,
input_x_embedded,
dtype=tf.float32)
# define helper for decoder
if is_inference:
self.start_tokens = tf.placeholder(tf.int32,
shape=[None],
name='start_tokens')
self.end_token = tf.placeholder(tf.int32, name='end_token')
helper = GreedyEmbeddingHelper(decoder_embedding,
self.start_tokens, self.end_token)
else:
self.target_ids = tf.placeholder(tf.int32,
shape=[None, None],
name='target_ids')
self.decoder_seq_length = tf.placeholder(tf.int32,
shape=[None],
name='batch_seq_length')
with tf.device('/cpu:0'):
target_embeddeds = tf.nn.embedding_lookup(
decoder_embedding, self.target_ids)
helper = TrainingHelper(target_embeddeds, self.decoder_seq_length)
with tf.variable_scope('decoder'):
fc_layer = Dense(decoder_vocab_size)
decoder_cell = self._get_simple_lstm(rnn_size, layer_size)
decoder = BasicDecoder(decoder_cell, helper, encoder_state,
fc_layer)
logits, final_state, final_sequence_lengths = dynamic_decode(decoder)
if not is_inference:
targets = tf.reshape(self.target_ids, [-1])
logits_flat = tf.reshape(logits.rnn_output,
[-1, decoder_vocab_size])
print 'shape logits_flat:{}'.format(logits_flat.shape)
print 'shape logits:{}'.format(logits.rnn_output.shape)
self.cost = tf.losses.sparse_softmax_cross_entropy(
targets, logits_flat)
# define train op
tvars = tf.trainable_variables()
grads, _ = tf.clip_by_global_norm(tf.gradients(self.cost, tvars),
grad_clip)
optimizer = tf.train.AdamOptimizer(1e-3)
self.train_op = optimizer.apply_gradients(zip(grads, tvars))
else:
self.prob = tf.nn.softmax(logits)
tf.contrib.rnn.LSTMStateTuple(c=encoder_last_state_c,
h=encoder_last_state_h))
encoder_last_state = tuple(encoder_last_state)
#batch_size = batch_size * beam_width
######################################################### ends building encoder
# building training decoder, no beam search
with tf.variable_scope('shared_attention_mechanism'):
attention_mechanism = seq2seq.BahdanauAttention(
num_units=hidden_dim * 2,
memory=encoder_outputs,
memory_sequence_length=encoder_inputs_length)
global_decoder_cell = tf.contrib.rnn.MultiRNNCell([
tf.nn.rnn_cell.BasicLSTMCell(hidden_dim * 2) for _ in range(num_layers)
])
projection_layer = Dense(label_dim)
decoder_cell = seq2seq.AttentionWrapper(
cell=global_decoder_cell,
#tf.nn.rnn_cell.BasicLSTMCell(hidden_dim*2),
attention_mechanism=attention_mechanism,
attention_layer_size=hidden_dim * 2)
#input_vectors = tf.nn.embedding_lookup(tgt_w, decoder_inputs)
print(decoder_inputs.shape, decoder_inputs.shape)
#decoder training
training_helper = seq2seq.TrainingHelper(
inputs=decoder_inputs_train,
sequence_length=tf.tile(tf.constant([15], dtype=tf.int32),
[batch_size]), #decoder_inputs_length_train,
time_major=False)
#print(decoder_cell.zero_state(batch_size,tf.float32))
def __init__(self, data, args, embed):
with tf.variable_scope("input"):
with tf.variable_scope("embedding"):
# build the embedding table and embedding input
if embed is None:
# initialize the embedding randomly
self.embed = tf.get_variable('embed', [data.vocab_size, args.embedding_size], tf.float32)
else:
# initialize the embedding by pre-trained word vectors
self.embed = tf.get_variable('embed', dtype=tf.float32, initializer=embed)
self.sentence = tf.placeholder(tf.int32, (None, None), 'sen_inps') # batch*len
self.sentence_length = tf.placeholder(tf.int32, (None,), 'sen_lens') # batch
self.use_prior = tf.placeholder(dtype=tf.bool, name="use_prior")
batch_size, batch_len = tf.shape(self.sentence)[0], tf.shape(self.sentence)[1]
self.decoder_max_len = batch_len - 1
self.encoder_input = tf.nn.embedding_lookup(self.embed, self.sentence) # batch*len*unit
self.encoder_len = self.sentence_length
decoder_input = tf.split(self.sentence, [self.decoder_max_len, 1], 1)[0] # no eos_id
self.decoder_input = tf.nn.embedding_lookup(self.embed, decoder_input) # batch*(len-1)*unit
self.decoder_target = tf.split(self.sentence, [1, self.decoder_max_len], 1)[1] # no go_id, batch*(len-1)
self.decoder_len = self.sentence_length - 1
self.decoder_mask = tf.sequence_mask(self.decoder_len, self.decoder_max_len, dtype=tf.float32) # batch*(len-1)
# initialize the training process
self.learning_rate = tf.Variable(float(args.lr), trainable=False, dtype=tf.float32)
self.learning_rate_decay_op = self.learning_rate.assign(self.learning_rate * args.lr_decay)
self.global_step = tf.Variable(0, trainable=False)
# build rnn_cell
cell_enc = tf.nn.rnn_cell.GRUCell(args.eh_size)
cell_dec = tf.nn.rnn_cell.GRUCell(args.dh_size)
# build encoder
with tf.variable_scope('encoder'):
encoder_output, encoder_state = dynamic_rnn(cell_enc, self.encoder_input,
self.encoder_len, dtype=tf.float32, scope="encoder_rnn")
with tf.variable_scope('recognition_net'):
recog_input = encoder_state
self.recog_mu = tf.layers.dense(inputs=recog_input, units=args.z_dim, activation=None, name='recog_mu')
self.recog_logvar = tf.layers.dense(inputs=recog_input, units=args.z_dim, activation=None, name='recog_logvar')
epsilon = tf.random_normal(tf.shape(self.recog_logvar), name="epsilon")
std = tf.exp(0.5 * self.recog_logvar)
self.recog_z = tf.add(self.recog_mu, tf.multiply(std, epsilon), name='recog_z')
self.kld = tf.reduce_mean(
0.5 * tf.reduce_sum(tf.exp(self.recog_logvar) + self.recog_mu * self.recog_mu - self.recog_logvar - 1,
axis=-1))
self.prior_z = tf.random_normal(tf.shape(self.recog_logvar), name="prior_z")
latent_sample = tf.cond(self.use_prior,
lambda: self.prior_z,
lambda: self.recog_z,
name='latent_sample')
dec_init_state = tf.layers.dense(inputs=latent_sample, units=args.dh_size, activation=None)
with tf.variable_scope("output_layer", initializer=tf.orthogonal_initializer()):
self.output_layer = Dense(data.vocab_size, kernel_initializer=tf.truncated_normal_initializer(stddev=0.1),
use_bias=True)
with tf.variable_scope("decode", initializer=tf.orthogonal_initializer()):
train_helper = tf.contrib.seq2seq.TrainingHelper(
inputs=self.decoder_input,
sequence_length=self.decoder_len
)
train_decoder = tf.contrib.seq2seq.BasicDecoder(
cell=cell_dec,
helper=train_helper,
initial_state=dec_init_state,
output_layer=self.output_layer
)
train_output, _, _ = tf.contrib.seq2seq.dynamic_decode(
decoder=train_decoder,
maximum_iterations=self.decoder_max_len,
impute_finished=True
)
logits = train_output.rnn_output
crossent = tf.nn.sparse_softmax_cross_entropy_with_logits(
labels=self.decoder_target, logits=logits)
crossent = tf.reduce_sum(crossent * self.decoder_mask)
self.sen_loss = crossent / tf.to_float(batch_size)
self.ppl_loss = crossent / tf.reduce_sum(self.decoder_mask)
self.decoder_distribution_teacher = tf.nn.log_softmax(logits)
with tf.variable_scope("decode", reuse=True):
infer_helper = tf.contrib.seq2seq.GreedyEmbeddingHelper(self.embed, tf.fill([batch_size], data.go_id),
data.eos_id)
infer_decoder = tf.contrib.seq2seq.BasicDecoder(
cell=cell_dec,
helper=infer_helper,
initial_state=dec_init_state,
output_layer=self.output_layer
)
infer_output, _, _ = tf.contrib.seq2seq.dynamic_decode(
decoder=infer_decoder,
maximum_iterations=self.decoder_max_len,
impute_finished=True
)
self.decoder_distribution = infer_output.rnn_output
self.generation_index = tf.argmax(tf.split(self.decoder_distribution,
[2, data.vocab_size - 2], 2)[1], 2) + 2 # for removing UNK
self.kl_weights = tf.minimum(tf.to_float(self.global_step) / args.full_kl_step, 1.0)
self.kl_loss = self.kl_weights * tf.maximum(self.kld, args.min_kl)
self.loss = self.sen_loss + self.kl_loss
# calculate the gradient of parameters and update
self.params = [k for k in tf.trainable_variables() if args.name in k.name]
opt = tf.train.MomentumOptimizer(learning_rate=self.learning_rate, momentum=args.momentum)
gradients = tf.gradients(self.loss, self.params)
clipped_gradients, self.gradient_norm = tf.clip_by_global_norm(gradients,
args.grad_clip)
self.update = opt.apply_gradients(zip(clipped_gradients, self.params),
global_step=self.global_step)
# save checkpoint
self.latest_saver = tf.train.Saver(write_version=tf.train.SaverDef.V2,
max_to_keep=args.checkpoint_max_to_keep, pad_step_number=True, keep_checkpoint_every_n_hours=1.0)
self.best_saver = tf.train.Saver(write_version=tf.train.SaverDef.V2,
max_to_keep=1, pad_step_number=True, keep_checkpoint_every_n_hours=1.0)
# create summary for tensorboard
self.create_summary(args)
def __init__(self,
n_cond,
n_pred,
hidden_dim,
n_layers=2,
input_dim=1,
learning_rate=0.001,
output_dim=1,
cell_type='GRU',
batch_size=100,
optimizer='Adam',
teacher_forcing_ratio=0.5,
use_scheduled_sampling=True):
"""
Construct graph
TrainingHelper just iterates over the dec_inputs passed to it
But in general a helper will take sample ids passed by basic decoder and used these to pick inputs
BasicDecoder just implements a step function which produces outputs and sample ids at each step
the outputs are the result of applying the rnn cell followed by an optional output layer
what I need is a version of GreedyEmbeddingHelper,
(A helper for use during inference.
Uses the argmax of the output (treated as logits) and passes the
result through an embedding layer to get the next input.)
"""
super().__init__(n_cond,
n_pred,
teacher_forcing_ratio=teacher_forcing_ratio,
use_scheduled_sampling=use_scheduled_sampling)
self.graph = tf.Graph()
with self.graph.as_default():
if use_scheduled_sampling:
self.sampling_probability = tf.placeholder(
tf.float32, shape=()
) # the probability of sampling from the outputs instead of reading directly from the inputs
self.teacher_force = tf.placeholder(tf.bool)
cells = []
self.keep_prob = tf.placeholder(tf.float32)
for i in range(n_layers):
with tf.variable_scope('RNN_{}'.format(i)):
if cell_type == 'GRU':
cells.append(
DropoutWrapper(tf.nn.rnn_cell.GRUCell(hidden_dim),
output_keep_prob=self.keep_prob))
elif cell_type == 'LSTM':
cells.append(
DropoutWrapper(
tf.nn.rnn_cell.BasicLSTMCell(hidden_dim),
output_keep_prob=self.keep_prob))
# cells.append(tf.nn.rnn_cell.BasicLSTMCell(...))
cell = tf.nn.rnn_cell.MultiRNNCell(cells)
self.inputs = tf.placeholder(tf.float32,
shape=(None, n_cond, input_dim))
self.go_sym = tf.placeholder(tf.float32,
shape=(None, 1, input_dim))
self.targets = tf.placeholder(tf.float32,
shape=(None, n_pred, input_dim))
dec_input = tf.concat([self.go_sym, self.targets[:, :-1, :]], 1)
enc_outputs, enc_state = tf.nn.dynamic_rnn(
cell, self.inputs, dtype=tf.float32) # returns outputs, state
# one of the features of the dynamic seq2seq is that it can handle variable length sequences
# but to do this you need to pad them to equal length then specify the lengths separately
# with constant lengths we still need to specify the lengths for traininghelper, but n.b. they're all the same
sequence_lengths = tf.constant(n_pred, shape=(batch_size, ))
output_layer = Dense(1, activation=None)
# if not use_scheduled_sampling:
# train_helper = tf.contrib.seq2seq.TrainingHelper(dec_input, sequence_lengths)
# else:
train_helper = tf.contrib.seq2seq.ScheduledOutputTrainingHelper(
dec_input,
sequence_lengths,
self.sampling_probability,
next_input_layer=Dense(1, activation=None))
def sampler(time, outputs, state):
# this isn't necessary, but just do it to get the types right
sample_ids = math_ops.cast(math_ops.argmax(outputs, axis=-1),
tf.int32)
return sample_ids
def looper(time, outputs, state, sample_ids):
# next_inputs_fn: callable that takes `(time, outputs, state, sample_ids)`
# and emits `(finished, next_inputs, next_state)`.
next_time = time + 1
finished = next_time >= sequence_lengths
next_inputs = tf.reshape(
outputs, (batch_size, input_dim)) # collapse the time axis
# I think this is the right thing to do based on looking at the shape of the outputs of TrainingHelper.initialize
return (finished, outputs, state)
inf_helper = tf.contrib.seq2seq.CustomHelper(
lambda: (array_ops.tile([False], [batch_size]),
tf.reshape(self.go_sym, (batch_size, input_dim))),
sampler, looper) # initialize fn, sample fn, next_inputs fn
# initialize_fn: callable that returns `(finished, next_inputs)`
# for the first iteration.
# sample_fn: callable that takes `(time, outputs, state)`
# next_inputs_fn - see note on looper
#https://github.com/tensorflow/tensorflow/issues/11540
train_decoder = tf.contrib.seq2seq.BasicDecoder(
cell=cell,
helper=train_helper,
initial_state=enc_state,
output_layer=output_layer)
inf_decoder = tf.contrib.seq2seq.BasicDecoder(
cell=cell,
helper=inf_helper,
initial_state=enc_state,
output_layer=output_layer)
outputs, states, sequence_lengths = tf.cond(
self.teacher_force, lambda: tf.contrib.seq2seq.dynamic_decode(
decoder=train_decoder),
lambda: tf.contrib.seq2seq.dynamic_decode(decoder=inf_decoder))
# outputs, states, sequence_lengths = tf.contrib.seq2seq.dynamic_decode(decoder=train_decoder)
# here outputs is an instance of class BasicDecoderOutput, with attrs rnn_output, sample_ids
self.preds = outputs.rnn_output
self.loss = tf.reduce_mean(tf.abs(self.preds - self.targets))
if optimizer == 'Adam':
self.optimizer = tf.train.AdamOptimizer(learning_rate)
elif optimizer == 'RMSProp':
self.optimizer = tf.train.RMSPropOptimizer(learning_rate,
decay=0.92,
momentum=0.5)
self.train_op = self.optimizer.minimize(self.loss)
tf.summary.scalar('loss', self.loss)
self.summary_op = tf.summary.merge_all()
self.saver = tf.train.Saver()
self.init = tf.global_variables_initializer()
def _init_decoder(self):
data_y = process_decoding_input(self.data_y, self.vocab_to_int_y,
self.batch_size)
self.dec_embeddings = tf.Variable(tf.random_uniform(
[self.vocab_size_y, self.embedding_size], -1.0, 1.0),
dtype=tf.float32)
dec_embedded = tf.nn.embedding_lookup(self.dec_embeddings, data_y)
with tf.variable_scope("decoder"):
dec_cell = rnn_cell(self.cell_size, self.dec_num_layers,
self.dec_keep_prob)
out_layer = Dense(self.vocab_size_y,
kernel_initializer=tf.truncated_normal_initializer(
mean=0.0, stddev=0.1))
att_mechanism = seq2seq.BahdanauAttention(self.cell_size,
self.enc_outputs,
self.x_length,
normalize=False)
dec_cell = seq2seq.DynamicAttentionWrapper(
dec_cell, att_mechanism, attention_size=self.cell_size)
init_state = seq2seq.DynamicAttentionWrapperState(
cell_state=self.enc_states[0],
attention=_zero_state_tensors(self.cell_size, self.batch_size,
tf.float32))
with tf.variable_scope("decoding"):
train_helper = seq2seq.TrainingHelper(
dec_embedded, sequence_length=self.y_length, time_major=False)
train_decoder = seq2seq.BasicDecoder(dec_cell, train_helper,
init_state, out_layer)
train_out, _ = seq2seq.dynamic_decode(
train_decoder,
output_time_major=False,
impute_finished=True,
maximum_iterations=self.max_length,
swap_memory=True)
self.decoder_train = train_out.rnn_output
with tf.variable_scope("decoding", reuse=True):
start_tokens = tf.tile(
tf.constant([self.vocab_to_int_y[START]], dtype=tf.int32),
[self.batch_size])
infer_helper = seq2seq.GreedyEmbeddingHelper(
embedding=self.dec_embeddings,
start_tokens=start_tokens,
end_token=self.vocab_to_int_y[STOP])
infer_decoder = seq2seq.BasicDecoder(dec_cell, infer_helper,
init_state, out_layer)
infer_out, _ = seq2seq.dynamic_decode(
infer_decoder,
output_time_major=False,
impute_finished=True,
maximum_iterations=self.max_length)
self.decoder_inference = infer_out.sample_id
tf.identity(self.decoder_train, 'decoder_train')
tf.identity(self.decoder_inference, 'decoder_inference')
def build_graph(self):
with tf.variable_scope('input'):
self.inputs = tf.placeholder(tf.int32, [None, None], name='inputs')
self.targets = tf.placeholder(tf.int32, [None, None],
name='targets')
self.learning_rate = tf.placeholder(tf.float32,
name='learning_rate')
self.target_sequence_length = tf.placeholder(
tf.int32, (None, ), name='target_sequence_length')
self.max_target_sequence_length = tf.reduce_max(
self.target_sequence_length, name='max_target_length')
self.source_sequence_length = tf.placeholder(
tf.int32, (None, ), name='source_sequence_length')
with tf.variable_scope('encoder'):
encoder_embed_input = tf.contrib.layers.embed_sequence(
self.inputs, len(self.source_letter_to_int),
self.config.encoding_embedding_size)
encoder_cell = tf.contrib.rnn.MultiRNNCell([
self.get_lstm_cell(self.config.rnn_size)
for _ in range(self.config.rnn_layers)
])
encoder_output, encoder_state = tf.nn.dynamic_rnn(
encoder_cell,
encoder_embed_input,
sequence_length=self.source_sequence_length,
dtype=tf.float32)
with tf.variable_scope('decoder'):
# 1. embedding
decoder_input = self.process_decoder_input(
self.targets, self.target_letter_to_int,
self.config.batch_size)
target_vocab_size = len(self.target_letter_to_int)
decoder_embeddings = tf.Variable(
tf.random_uniform(
[target_vocab_size, self.config.decoding_embedding_size]))
decoder_embed_input = tf.nn.embedding_lookup(
decoder_embeddings, decoder_input)
# decoder_embed_input = tf.contrib.layers.embed_sequence(decoder_input, target_vocab_size, self.config.decoding_embedding_size)
# 2. construct the rnn
decoder_cell = tf.contrib.rnn.MultiRNNCell([
self.get_lstm_cell(self.config.rnn_size)
for _ in range(self.config.rnn_layers)
])
# 3. output fully connected
output_layer = Dense(
target_vocab_size,
kernel_initializer=tf.truncated_normal_initializer(mean=0.0,
stddev=0.1))
if self.mode == 'train':
training_helper = tf.contrib.seq2seq.TrainingHelper(
inputs=decoder_embed_input,
sequence_length=self.target_sequence_length,
time_major=False)
training_decoder = tf.contrib.seq2seq.BasicDecoder(
decoder_cell, training_helper, encoder_state, output_layer)
decoder_output, _, _ = tf.contrib.seq2seq.dynamic_decode(
training_decoder,
impute_finished=True,
maximum_iterations=self.max_target_sequence_length)
else:
start_tokens = tf.tile(
tf.constant([self.target_letter_to_int['<GO>']],
dtype=tf.int32), [self.config.batch_size],
name='start_tokens')
predicting_helper = tf.contrib.seq2seq.GreedyEmbeddingHelper(
decoder_embeddings, start_tokens,
self.target_letter_to_int['<EOS>'])
predicting_decoder = tf.contrib.seq2seq.BasicDecoder(
decoder_cell, predicting_helper, encoder_state,
output_layer)
decoder_output, _, _ = tf.contrib.seq2seq.dynamic_decode(
predicting_decoder,
impute_finished=True,
maximum_iterations=self.max_target_sequence_length)
with tf.variable_scope('loss'):
training_logits = tf.identity(decoder_output.rnn_output, 'logits')
predicting_logits = tf.identity(
decoder_output.sample_id,
name='predictions') # used for predict
masks = tf.sequence_mask(self.target_sequence_length,
self.max_target_sequence_length,
dtype=tf.float32,
name='masks')
self.loss = tf.contrib.seq2seq.sequence_loss(
training_logits, self.targets, masks)
with tf.name_scope('optimize'):
# optimizer = tf.train.AdamOptimizer(lr)
# gradients = optimizer.compute_gradients(cost)
# capped_gradients = [(tf.clip_by_value(grad, -5., 5.), var) for grad, var in gradients if grad is not None]
# train_op = optimizer.apply_gradients(capped_gradients)
training_variables = tf.trainable_variables()
grads, _ = tf.clip_by_global_norm(
tf.gradients(self.loss, training_variables), 5)
optimizer = tf.train.AdamOptimizer(self.learning_rate)
self.train_op = optimizer.apply_gradients(zip(
grads, training_variables),
name='train_op')
def _build_model_op(self):
# self attention
if self.unimodal:
input = self.input
else:
if self.attn_fusion:
input = self.self_attention(self.a_input, self.v_input,
self.t_input, '')
input = input * tf.expand_dims(self.mask, axis=-1)
else:
input = tf.concat([self.a_input, self.v_input, self.t_input],
axis=-1)
# input = tf.nn.dropout(input, 1-self.lstm_inp_dropout)
self.gru_output = self.BiGRU(input, 100, 'gru', 1 - self.lstm_dropout)
self.inter = tf.nn.dropout(self.gru_output, 1 - self.dropout_lstm_out)
# self.inter = self.gru_output
if self.attn_2:
self.inter = self.self_attention_2(self.inter, '')
init = tf.glorot_uniform_initializer(seed=self.seed, dtype=tf.float32)
if self.unimodal:
self.inter1 = Dense(
100,
activation=tf.nn.tanh,
kernel_initializer=init,
kernel_regularizer=tf.contrib.layers.l2_regularizer(0.001))(
self.inter)
else:
self.inter1 = Dense(
200,
activation=tf.nn.relu,
kernel_initializer=init,
kernel_regularizer=tf.contrib.layers.l2_regularizer(0.001))(
self.inter)
self.inter1 = self.inter1 * tf.expand_dims(self.mask, axis=-1)
self.inter1 = Dense(
200,
activation=tf.nn.relu,
kernel_initializer=init,
kernel_regularizer=tf.contrib.layers.l2_regularizer(0.001))(
self.inter1)
self.inter1 = self.inter1 * tf.expand_dims(self.mask, axis=-1)
self.inter1 = Dense(
200,
activation=tf.nn.relu,
kernel_initializer=init,
kernel_regularizer=tf.contrib.layers.l2_regularizer(0.001))(
self.inter1)
self.inter1 = self.inter1 * tf.expand_dims(self.mask, axis=-1)
self.inter1 = tf.nn.dropout(self.inter1, 1 - self.dropout)
self.output = Dense(
self.emotions,
kernel_initializer=init,
kernel_regularizer=tf.contrib.layers.l2_regularizer(0.001))(
self.inter1)
# print('self.output', self.output.get_shape())
self.preds = tf.nn.softmax(self.output)
# To calculate the number correct, we want to count padded steps as incorrect
correct = tf.cast(
tf.equal(tf.argmax(self.preds, -1, output_type=tf.int32),
tf.argmax(self.y, -1, output_type=tf.int32)),
tf.int32) * tf.cast(self.mask, tf.int32)
# To calculate accuracy we want to divide by the number of non-padded time-steps,
# rather than taking the mean
self.accuracy = tf.reduce_sum(tf.cast(
correct, tf.float32)) / tf.reduce_sum(
tf.cast(self.seq_len, tf.float32))
# y = tf.argmax(self.y, -1)
loss = tf.nn.softmax_cross_entropy_with_logits_v2(logits=self.output,
labels=self.y)
loss = loss * self.mask
self.loss = tf.reduce_sum(loss) / tf.reduce_sum(self.mask)
def build_latent_space(self):
with tf.name_scope("latent_space"):
self.z_tilda = Dense(self.latent_dim, name='z_tilda')(self.h_N) # [batch_size x latent_dim]
def build_decoder(self):
print("building decoder and attention..")
with tf.variable_scope('decoder'):
# Building decoder_cell and decoder_initial_state
self.decoder_cell, self.decoder_initial_state = self.build_decoder_cell(
)
# Initialize decoder embeddings to have variance=1.
sqrt3 = math.sqrt(3) # Uniform(-sqrt(3), sqrt(3)) has variance=1.
initializer = tf.random_uniform_initializer(-sqrt3,
sqrt3,
dtype=self.dtype)
self.decoder_embeddings = tf.get_variable(
name='embedding',
shape=[self.num_decoder_symbols, self.embedding_size],
initializer=initializer,
dtype=self.dtype)
# Input projection layer to feed embedded inputs to the cell
# ** Essential when use_residual=True to match input/output dims
input_layer = Dense(self.hidden_units,
dtype=self.dtype,
name='input_projection')
# Output projection layer to convert cell_outputs to logits
output_layer = Dense(self.num_decoder_symbols,
name='output_projection')
if self.mode == 'train':
# decoder_inputs_embedded: [batch_size, max_time_step + 1, embedding_size]
self.decoder_inputs_embedded = tf.nn.embedding_lookup(
params=self.decoder_embeddings,
ids=self.decoder_inputs_train)
# Embedded inputs having gone through input projection layer
self.decoder_inputs_embedded = input_layer(
self.decoder_inputs_embedded)
# Helper to feed inputs for training: read inputs from dense ground truth vectors
training_helper = seq2seq.TrainingHelper(
inputs=self.decoder_inputs_embedded,
sequence_length=self.decoder_inputs_length_train,
time_major=False,
name='training_helper')
training_decoder = seq2seq.BasicDecoder(
cell=self.decoder_cell,
helper=training_helper,
initial_state=self.decoder_initial_state,
output_layer=output_layer)
#output_layer=None)
# Maximum decoder time_steps in current batch
max_decoder_length = tf.reduce_max(
self.decoder_inputs_length_train)
# decoder_outputs_train: BasicDecoderOutput
# namedtuple(rnn_outputs, sample_id)
# decoder_outputs_train.rnn_output: [batch_size, max_time_step + 1, num_decoder_symbols] if output_time_major=False
# [max_time_step + 1, batch_size, num_decoder_symbols] if output_time_major=True
# decoder_outputs_train.sample_id: [batch_size], tf.int32
(self.decoder_outputs_train, self.decoder_last_state_train,
self.decoder_outputs_length_train) = (seq2seq.dynamic_decode(
decoder=training_decoder,
output_time_major=False,
impute_finished=True,
maximum_iterations=max_decoder_length))
# More efficient to do the projection on the batch-time-concatenated tensor
# logits_train: [batch_size, max_time_step + 1, num_decoder_symbols]
# self.decoder_logits_train = output_layer(self.decoder_outputs_train.rnn_output)
self.decoder_logits_train = tf.identity(
self.decoder_outputs_train.rnn_output)
# Use argmax to extract decoder symbols to emit
self.decoder_pred_train = tf.argmax(self.decoder_logits_train,
axis=-1,
name='decoder_pred_train')
# masks: masking for valid and padded time steps, [batch_size, max_time_step + 1]
masks = tf.sequence_mask(
lengths=self.decoder_inputs_length_train,
maxlen=max_decoder_length,
dtype=self.dtype,
name='masks')
def class_weighted_loss(labels, logits):
class_weights = tf.constant([
0.00017234778799135608, 0.00017234778799135608,
0.00017234778799135608, 1.6821366229319637e-05,
4.898869308918329e-05, 7.106575604186823e-05,
7.126891354944498e-05, 7.514392550863835e-05,
7.719102618435312e-05, 8.89973910758995e-05,
0.00010430076292140834, 0.00010567508046918493,
0.00011254233356378444, 0.00013745981039146453,
0.00015365550520395147, 0.00016343173716428013,
0.00016623641703291143, 0.00018462654135821253,
0.0001873476479039208, 0.00018800477750021655,
0.00020981274294876723, 0.00021602805964389768,
0.00024354484846033354, 0.00024936107032012903,
0.0002495739348066665, 0.000319111899575184,
0.00033594586064125193, 0.0003818581956683335,
0.0003838636576651593, 0.0005417806138677063,
0.0006711205600832021, 0.0006750650134170244,
0.0006953534538202605, 0.0007032603813511271,
0.0007207552048226591, 0.0007264535179396215,
0.0007633538390502503, 0.000891602363160162,
0.0009813883808113227, 0.0010641991144668115,
0.0011028839931134101, 0.0012656472742694626,
0.0013067898106130453, 0.0013988733031399323,
0.0016671901108961662, 0.0017748398034871436,
0.0022286969673726295, 0.0022647955802244397,
0.0022727983914619817, 0.002481488984505173,
0.002566647824356508, 0.0026578592759658715,
0.002682243306020604, 0.002818588715090889,
0.002964064261676225, 0.0029888566207422903,
0.0030339714376591553, 0.0032127969269917125,
0.0032616731479905726, 0.0033361096721148385,
0.00424275689171333, 0.004594299605598149,
0.004750383639466329, 0.005306946739139776,
0.005497452519519153, 0.005911782580732912,
0.007162605175765489, 0.007194652626216341,
0.007496526162980663, 0.007960420108709664,
0.007960420108709664, 0.008691918172753256,
0.009110509132914177, 0.011323977901122198,
0.011652209144632988, 0.012711500885054168,
0.013180367720978298, 0.015169857188295775,
0.016242473353124773, 0.022971498027990745,
0.024000072566557496, 0.024549692548997745,
0.029504676366226647, 0.035733441376874495,
0.03828583004665124, 0.03874710510745427,
0.058472904071249165, 0.0630590141944844,
0.08040024309796762, 0.3573344137687449
])
weights = tf.gather(class_weights, labels)
unweighted_losses = tf.nn.sparse_softmax_cross_entropy_with_logits(
labels=labels, logits=logits)
return unweighted_losses * weights
# Computes per word average cross-entropy over a batch
# Internally calls 'nn_ops.sparse_softmax_cross_entropy_with_logits' by default
if self.loss_type == 'weighted':
print 'using weighted loss!'
self.loss = seq2seq.sequence_loss(
logits=self.decoder_logits_train,
targets=self.decoder_targets_train,
weights=masks,
average_across_timesteps=True,
average_across_batch=True,
softmax_loss_function=class_weighted_loss,
)
else:
self.loss = seq2seq.sequence_loss(
logits=self.decoder_logits_train,
targets=self.decoder_targets_train,
weights=masks,
average_across_timesteps=True,
average_across_batch=True,
)
# Training summary for the current batch_loss
tf.summary.scalar('loss', self.loss)
# Contruct graphs for minimizing loss
self.init_optimizer()
elif self.mode == 'decode':
# Start_tokens: [batch_size,] `int32` vector
start_tokens = tf.ones([
self.batch_size,
], tf.int32) * data_utils.start_token
end_token = data_utils.end_token
def embed_and_input_proj(inputs):
return input_layer(
tf.nn.embedding_lookup(self.decoder_embeddings,
inputs))
if not self.use_beamsearch_decode:
# Helper to feed inputs for greedy decoding: uses the argmax of the output
decoding_helper = seq2seq.GreedyEmbeddingHelper(
start_tokens=start_tokens,
end_token=end_token,
embedding=embed_and_input_proj)
# Basic decoder performs greedy decoding at each time step
print("building greedy decoder..")
inference_decoder = seq2seq.BasicDecoder(
cell=self.decoder_cell,
helper=decoding_helper,
initial_state=self.decoder_initial_state,
output_layer=output_layer)
else:
# Beamsearch is used to approximately find the most likely translation
print("building beamsearch decoder..")
inference_decoder = beam_search_decoder.BeamSearchDecoder(
cell=self.decoder_cell,
embedding=embed_and_input_proj,
start_tokens=start_tokens,
end_token=end_token,
initial_state=self.decoder_initial_state,
beam_width=self.beam_width,
output_layer=output_layer,
)
# For GreedyDecoder, return
# decoder_outputs_decode: BasicDecoderOutput instance
# namedtuple(rnn_outputs, sample_id)
# decoder_outputs_decode.rnn_output: [batch_size, max_time_step, num_decoder_symbols] if output_time_major=False
# [max_time_step, batch_size, num_decoder_symbols] if output_time_major=True
# decoder_outputs_decode.sample_id: [batch_size, max_time_step], tf.int32 if output_time_major=False
# [max_time_step, batch_size], tf.int32 if output_time_major=True
# For BeamSearchDecoder, return
# decoder_outputs_decode: FinalBeamSearchDecoderOutput instance
# namedtuple(predicted_ids, beam_search_decoder_output)
# decoder_outputs_decode.predicted_ids: [batch_size, max_time_step, beam_width] if output_time_major=False
# [max_time_step, batch_size, beam_width] if output_time_major=True
# decoder_outputs_decode.beam_search_decoder_output: BeamSearchDecoderOutput instance
# namedtuple(scores, predicted_ids, parent_ids)
(self.decoder_outputs_decode, self.decoder_last_state_decode,
self.decoder_outputs_length_decode) = (
seq2seq.dynamic_decode(
decoder=inference_decoder,
output_time_major=False,
#impute_finished=True, # error occurs
maximum_iterations=self.max_decode_step))
if not self.use_beamsearch_decode:
# decoder_outputs_decode.sample_id: [batch_size, max_time_step]
# Or use argmax to find decoder symbols to emit:
# self.decoder_pred_decode = tf.argmax(self.decoder_outputs_decode.rnn_output,
# axis=-1, name='decoder_pred_decode')
# Here, we use expand_dims to be compatible with the result of the beamsearch decoder
# decoder_pred_decode: [batch_size, max_time_step, 1] (output_major=False)
self.decoder_pred_decode = tf.expand_dims(
self.decoder_outputs_decode.sample_id, -1)
else:
# Use beam search to approximately find the most likely translation
# decoder_pred_decode: [batch_size, max_time_step, beam_width] (output_major=False)
self.decoder_pred_decode = self.decoder_outputs_decode.predicted_ids
def build_decoder(self):
print("building decoder and attention..")
with tf.variable_scope('decoder'):
# Building decoder_cell and decoder_initial_state
self.decoder_cell, self.decoder_initial_state = self.build_decoder_cell(
)
# Initialize decoder embeddings to have variance=1.
sqrt3 = math.sqrt(3) # Uniform(-sqrt(3), sqrt(3)) has variance=1.
initializer = tf.random_uniform_initializer(-sqrt3,
sqrt3,
dtype=self.dtype)
self.decoder_embeddings = tf.get_variable(
name='embedding',
shape=[self.num_decoder_symbols, self.embedding_size],
initializer=initializer,
dtype=self.dtype)
# Input projection layer to feed embedded inputs to the cell
# ** Essential when use_residual=True to match input/output dims
input_layer = Dense(self.hidden_units,
dtype=self.dtype,
name='input_projection')
# Output projection layer to convert cell_outputs to logits
output_layer = Dense(self.num_decoder_symbols,
name='output_projection')
if self.mode == 'train':
# decoder_inputs_embedded: [batch_size, max_time_step + 1, embedding_size]
self.decoder_inputs_embedded = tf.nn.embedding_lookup(
params=self.decoder_embeddings,
ids=self.decoder_inputs_train)
# Embedded inputs having gone through input projection layer
self.decoder_inputs_embedded = input_layer(
self.decoder_inputs_embedded)
# Helper to feed inputs for training: read inputs from dense ground truth vectors
training_helper = seq2seq.TrainingHelper(
inputs=self.decoder_inputs_embedded,
sequence_length=self.decoder_inputs_length_train,
time_major=False,
name='training_helper')
training_decoder = seq2seq.BasicDecoder(
cell=self.decoder_cell,
helper=training_helper,
initial_state=self.decoder_initial_state,
output_layer=output_layer)
#output_layer=None)
# Maximum decoder time_steps in current batch
max_decoder_length = tf.reduce_max(
self.decoder_inputs_length_train)
# decoder_outputs_train: BasicDecoderOutput
# namedtuple(rnn_outputs, sample_id)
# decoder_outputs_train.rnn_output: [batch_size, max_time_step + 1, num_decoder_symbols] if output_time_major=False
# [max_time_step + 1, batch_size, num_decoder_symbols] if output_time_major=True
# decoder_outputs_train.sample_id: [batch_size], tf.int32
(self.decoder_outputs_train, self.decoder_last_state_train,
self.decoder_outputs_length_train) = (seq2seq.dynamic_decode(
decoder=training_decoder,
output_time_major=False,
impute_finished=True,
maximum_iterations=max_decoder_length))
# More efficient to do the projection on the batch-time-concatenated tensor
# logits_train: [batch_size, max_time_step + 1, num_decoder_symbols]
# self.decoder_logits_train = output_layer(self.decoder_outputs_train.rnn_output)
self.decoder_logits_train = tf.identity(
self.decoder_outputs_train.rnn_output)
# Use argmax to extract decoder symbols to emit
self.decoder_pred_train = tf.argmax(self.decoder_logits_train,
axis=-1,
name='decoder_pred_train')
# masks: masking for valid and padded time steps, [batch_size, max_time_step + 1]
masks = tf.sequence_mask(
lengths=self.decoder_inputs_length_train,
maxlen=max_decoder_length,
dtype=self.dtype,
name='masks')
# Computes per word average cross-entropy over a batch
# Internally calls 'nn_ops.sparse_softmax_cross_entropy_with_logits' by default
self.loss = seq2seq.sequence_loss(
logits=self.decoder_logits_train,
targets=self.decoder_targets_train,
weights=masks,
average_across_timesteps=True,
average_across_batch=True,
)
# Training summary for the current batch_loss
tf.summary.scalar('loss', self.loss)
# Contruct graphs for minimizing loss
self.init_optimizer()
elif self.mode == 'decode':
# Start_tokens: [batch_size,] `int32` vector
start_tokens = tf.ones([
self.batch_size,
], tf.int32) * data_utils.start_token
end_token = data_utils.end_token
def embed_and_input_proj(inputs):
return input_layer(
tf.nn.embedding_lookup(self.decoder_embeddings,
inputs))
if not self.use_beamsearch_decode:
# Helper to feed inputs for greedy decoding: uses the argmax of the output
decoding_helper = seq2seq.GreedyEmbeddingHelper(
start_tokens=start_tokens,
end_token=end_token,
embedding=embed_and_input_proj)
# Basic decoder performs greedy decoding at each time step
print("building greedy decoder..")
inference_decoder = seq2seq.BasicDecoder(
cell=self.decoder_cell,
helper=decoding_helper,
initial_state=self.decoder_initial_state,
output_layer=output_layer)
else:
# Beamsearch is used to approximately find the most likely translation
print("building beamsearch decoder..")
inference_decoder = beam_search_decoder.BeamSearchDecoder(
cell=self.decoder_cell,
embedding=embed_and_input_proj,
start_tokens=start_tokens,
end_token=end_token,
initial_state=self.decoder_initial_state,
beam_width=self.beam_width,
output_layer=output_layer,
)
# For GreedyDecoder, return
# decoder_outputs_decode: BasicDecoderOutput instance
# namedtuple(rnn_outputs, sample_id)
# decoder_outputs_decode.rnn_output: [batch_size, max_time_step, num_decoder_symbols] if output_time_major=False
# [max_time_step, batch_size, num_decoder_symbols] if output_time_major=True
# decoder_outputs_decode.sample_id: [batch_size, max_time_step], tf.int32 if output_time_major=False
# [max_time_step, batch_size], tf.int32 if output_time_major=True
# For BeamSearchDecoder, return
# decoder_outputs_decode: FinalBeamSearchDecoderOutput instance
# namedtuple(predicted_ids, beam_search_decoder_output)
# decoder_outputs_decode.predicted_ids: [batch_size, max_time_step, beam_width] if output_time_major=False
# [max_time_step, batch_size, beam_width] if output_time_major=True
# decoder_outputs_decode.beam_search_decoder_output: BeamSearchDecoderOutput instance
# namedtuple(scores, predicted_ids, parent_ids)
(self.decoder_outputs_decode, self.decoder_last_state_decode,
self.decoder_outputs_length_decode) = (
seq2seq.dynamic_decode(
decoder=inference_decoder,
output_time_major=False,
#impute_finished=True, # error occurs
maximum_iterations=self.max_decode_step))
if not self.use_beamsearch_decode:
# decoder_outputs_decode.sample_id: [batch_size, max_time_step]
# Or use argmax to find decoder symbols to emit:
# self.decoder_pred_decode = tf.argmax(self.decoder_outputs_decode.rnn_output,
# axis=-1, name='decoder_pred_decode')
# Here, we use expand_dims to be compatible with the result of the beamsearch decoder
# decoder_pred_decode: [batch_size, max_time_step, 1] (output_major=False)
self.decoder_pred_decode = tf.expand_dims(
self.decoder_outputs_decode.sample_id, -1)
else:
# Use beam search to approximately find the most likely translation
# decoder_pred_decode: [batch_size, max_time_step, beam_width] (output_major=False)
self.decoder_pred_decode = self.decoder_outputs_decode.predicted_ids
def _inference(self):
self.embedding = tf.get_variable("embedding",
[self.VOL_SIZE, self.EMBEDDING_SIZE],
dtype=tf.float32)
num_classes = self.VOL_SIZE
# use softmax to map decoder_output to number(0-5,EOS)
self.softmax_w = self.variable(name="softmax_w",
shape=[self.HIDDEN_UNIT, num_classes])
self.softmax_b = self.variable(name="softmax_b", shape=[num_classes])
# prepare to compute c_i = \sum a_{ij}h_j, encoder_states are h_js
hidden_states = []
self.W_a = self.variable(name="attention_w_a",
shape=[self.HIDDEN_UNIT, self.HIDDEN_UNIT])
self.U_a = self.variable(name="attention_u_a",
shape=[self.HIDDEN_UNIT, self.HIDDEN_UNIT])
self.v_a = self.variable(name="attention_v_a",
shape=[1, self.EMBEDDING_SIZE])
# connect intention with decoder
# connect intention with intention
self.I_E = self.variable(name="intention_e",
shape=[self.HIDDEN_UNIT, self.HIDDEN_UNIT])
self.encoder_to_intention_b = self.variable(name="encoder_intention_b",
shape=[self.HIDDEN_UNIT])
self.I_I = self.variable(name="intention_i",
shape=[self.HIDDEN_UNIT, self.HIDDEN_UNIT])
self.intention_to_decoder_b = self.variable(name="intention_decoder_b",
shape=[self.HIDDEN_UNIT])
# self.C = self.variable(name="attention_C", shape=[self.HIDDEN_UNIT, self.HIDDEN_UNIT])
# encoder_params = rnn_encoder.StackBidirectionalRNNEncoder.default_params()
# encoder_params["rnn_cell"]["cell_params"][
# "num_units"] = self.HIDDEN_UNIT
# encoder_params["rnn_cell"]["cell_class"] = "BasicLSTMCell"
# encoder_params["rnn_cell"]["num_layers"] = self.N_LAYER
with tf.variable_scope("encoder") as scope:
encoder_embedding_vectors = tf.nn.embedding_lookup(
self.embedding, self.encoder_inputs)
encoder_fw_cell = self.stacked_rnn(self.HIDDEN_UNIT)
encoder_bw_cell = self.stacked_rnn(self.HIDDEN_UNIT)
self.encoder_initial_fw_state = self.get_state_variables(
self.batch_size, encoder_fw_cell)
self.encoder_initial_bw_state = self.get_state_variables(
self.batch_size, encoder_bw_cell)
((outputs_fw, outputs_bw), (state_fw, state_bw)) = \
tf.nn.bidirectional_dynamic_rnn(cell_fw=encoder_fw_cell, cell_bw=encoder_bw_cell,
inputs=encoder_embedding_vectors,
sequence_length=self.encoder_inputs_length,
initial_state_fw=self.encoder_initial_fw_state,
initial_state_bw=self.encoder_initial_bw_state,
dtype=tf.float32)
encoder_final_state_c = tf.concat(
(state_fw[self.N_LAYER - 1][0], state_bw[self.N_LAYER - 1][0]), 1)
encoder_final_state_h = tf.concat(
(state_fw[self.N_LAYER - 1][1], state_bw[self.N_LAYER - 1][1]), 1)
encoder_final_state = tf.nn.rnn_cell.LSTMStateTuple(
c=encoder_final_state_c, h=encoder_final_state_h)
hidden_state = tf.reshape(encoder_final_state[1],
shape=(-1, self.HIDDEN_UNIT * 2))
# compute U_a*h_j quote:"this vector can be pre-computed.. U_a is R^n * n, h_j is R^n"
# U_ah = []
# for h in hidden_states:
# ## h.shape is BATCH, HIDDEN_UNIT
# u_ahj = tf.matmul(h, self.U_a)
# U_ah.append(u_ahj)
# hidden_states = tf.stack(hidden_states)
self.decoder_outputs = []
# self.internal = []
#
with tf.variable_scope("decoder") as scope:
self.decoder_cell = self.stacked_rnn(self.HIDDEN_UNIT)
self.decoder_state = self.get_state_variables(
self.batch_size, self.decoder_cell)
#
# building intention network
with tf.variable_scope("intention") as scope:
self.intention_cell = self.stacked_rnn(self.HIDDEN_UNIT)
self.intention_state = self.get_state_variables(
self.batch_size, self.intention_cell)
if self.turn_index > 0:
tf.get_variable_scope().reuse_variables()
# for encoder_step_hidden_state in hidden_states:
intention_output, intention_state = self.intention_cell(
hidden_state, self.intention_state)
# # #
# cT_encoder= self._concat_hidden(encoder_state)
initial_decoder_state = []
for i in xrange(len(intention_state)):
b = intention_state[i]
c = b[0]
h = b[1]
Dh = tf.tanh(tf.matmul(h, self.I_I))
initial_decoder_state.append(tf.contrib.rnn.LSTMStateTuple(c, Dh))
# print(len(initial_decoder_state))
initial_decoder_state = tuple(initial_decoder_state)
print(initial_decoder_state)
# # intention_states.append(intention_hidden_state)
# intention_state = self.intention_state
# for encoder_step_hidden_state in hidden_states:
# intention_output, intention_state = self.intention_cell(encoder_step_hidden_state, intention_state)
# # intention_state = self.intention_state
# self.modified = []
# for layer in xrange(len(encoder_state)):
# layer_intention_state = encoder_state[layer]
# layer_last_encoder_state = self.encoder_state[layer]
# h = layer_intention_state[1]
# c = layer_intention_state[0]
# eh = layer_last_encoder_state[1]
# ec = layer_last_encoder_state[0]
# self.kernel_i = tf.add(tf.matmul(h, self.I_I), self.intention_to_decoder_b)
# self.kernel_e = tf.add(tf.matmul(eh, self.I_E), self.encoder_to_intention_b)
# self.h_ = tf.concat([self.kernel_e, self.kernel_i], axis=1)
# cc = tf.concat([c, ec], axis=1)
# layer = tf.contrib.rnn.LSTMStateTuple(cc, self.h_)
# self.modified.append(layer)
#
# *****************************************mark************************************************************
# with tf.variable_scope("decoder") as scope:
# if self.TRAINABLE:
# decoder_embedding_vectors = tf.nn.embedding_lookup(
# self.embedding, self.decoder_inputs)
# self.decoder_outputs, decoder_state = tf.nn.dynamic_rnn(cell=self.decoder_cell,
# inputs=decoder_embedding_vectors,
# sequence_length=self.decoder_inputs_length,
# initial_state=initial_decoder_state,
# dtype=tf.float32
# )
# self.intention_state_update_op = self.get_state_update_op(
# self.intention_state, intention_state)
# self.encoder_state_update_op = self.get_state_update_op(
# self.encoder_initial_fw_state, decoder_state)
# *****************************************mark end********************
# ***************try another way to decode*********************
with tf.variable_scope("decoder") as scope:
if self.TRAINABLE:
decoder_embedding_vectors = tf.nn.embedding_lookup(
self.embedding, self.decoder_inputs)
output_layer = Dense(
self.VOL_SIZE,
kernel_initializer=tf.truncated_normal_initializer(
mean=0.0, stddev=0.1))
self.max_target_sequence_length = tf.reduce_max(
self.decoder_inputs_length, name='max_target_len')
training_helper = tf.contrib.seq2seq.TrainingHelper(
inputs=decoder_embedding_vectors,
sequence_length=self.decoder_inputs_length,
time_major=False)
training_decoder = tf.contrib.seq2seq.BasicDecoder(
cell=self.decoder_cell,
helper=training_helper,
initial_state=initial_decoder_state,
output_layer=output_layer)
self.decoder_output, decoder_state, _ = tf.contrib.seq2seq.dynamic_decode(
training_decoder,
impute_finished=True,
maximum_iterations=self.max_target_sequence_length)
self.intention_state_update_op = self.get_state_update_op(
self.intention_state, intention_state)
self.encoder_state_update_op = self.get_state_update_op(
self.encoder_initial_fw_state, decoder_state)
else:
# https://github.com/tensorflow/tensorflow/issues/11598
# PREDICTING_DECODER ## METHOD 1
output_layer = Dense(
self.VOL_SIZE,
kernel_initializer=tf.truncated_normal_initializer(
mean=0.0, stddev=0.1))
greedy_helper = tf.contrib.seq2seq.GreedyEmbeddingHelper(embedding=self.embedding,\
start_tokens = tf.tile(tf.constant([self.data_config.GO_], dtype=tf.int32), [self.batch_size]),\
end_token = self.data_config.EOS_)
infer_decoder = tf.contrib.seq2seq.BasicDecoder(
cell=self.decoder_cell,
helper=greedy_helper,
initial_state=initial_decoder_state,
output_layer=output_layer)
self.decoder_output, decoder_state, final_sequence_lengths = tf.contrib.seq2seq.dynamic_decode(
infer_decoder,
impute_finished=True,
maximum_iterations=100)
logits = tf.identity(self.decoder_output.rnn_output, 'logits')
# self.predictions_ = tf.argmax(logits, axis=2)
time_major = tf.transpose(logits, [1, 0, 2])
print(time_major)
(self.predictions_, self.log_probabilities) = tf.nn.ctc_beam_search_decoder(inputs=time_major, \
sequence_length=final_sequence_lengths,\
beam_width=self.beam_width,
top_paths=self.paths,
merge_repeated=True)
def build_decoder(self):
with tf.variable_scope("decoder"):
decoder_cell, decoder_initial_state = self.build_decoder_cell()
# start tokens : [batch_size], which is fed to BeamsearchDecoder during inference
start_tokens = tf.ones([self.batch_size],
dtype=tf.int32) * data_util.ID_GO
end_token = data_util.ID_EOS
input_layer = Dense(self.state_size * 2, dtype=tf.float32,
name="input_layer")
output_layer = Dense(self.decoder_vocab_size,
name="output_projection")
if self.mode == "train":
# feed ground truth decoder input token every time step
decoder_input_lookup = tf.nn.embedding_lookup(
self.embedding_matrix, self.decoder_input)
decoder_input_lookup = input_layer(decoder_input_lookup)
training_helper = seq2seq.TrainingHelper(
inputs=decoder_input_lookup,
sequence_length=self.decoder_train_len,
name="training_helper")
training_decoder = seq2seq.BasicDecoder(cell=decoder_cell,
initial_state=decoder_initial_state,
helper=training_helper,
output_layer=output_layer)
# decoder_outputs_train: BasicDecoderOutput
# namedtuple(rnn_outputs, sample_id)
# decoder_outputs_train.rnn_output: [batch_size, max_time_step + 1, num_decoder_symbols] if output_time_major=False
# [max_time_step + 1, batch_size, num_decoder_symbols] if output_time_major=True
# decoder_outputs_train.sample_id: [batch_size], tf.int32
max_decoder_len = tf.reduce_max(self.decoder_train_len)
decoder_outputs_train, final_state, _ = seq2seq.dynamic_decode(
training_decoder, impute_finished=True, swap_memory=True,
maximum_iterations=max_decoder_len)
self.decoder_logits_train = tf.identity(
decoder_outputs_train.rnn_output)
decoder_pred = tf.argmax(self.decoder_logits_train, axis=2)
# sequence mask for get valid sequence except zero padding
weights = tf.sequence_mask(self.decoder_len,
maxlen=max_decoder_len,
dtype=tf.float32)
# compute cross entropy loss for all sequence prediction and ignore loss from zero padding
self.loss = seq2seq.sequence_loss(
logits=self.decoder_logits_train,
targets=self.decoder_target,
weights=weights, average_across_batch=True,
average_across_timesteps=True)
tf.summary.scalar("loss", self.loss)
with tf.variable_scope("train_optimizer") and tf.device(
"/device:GPU:1"):
# use AdamOptimizer and clip gradient by max_norm 5.0
# use global step for counting every iteration
params = tf.trainable_variables()
gradients = tf.gradients(self.loss, params)
clipped_gradients, _ = tf.clip_by_global_norm(gradients,
5.0)
learning_rate = tf.train.exponential_decay(self.lr,
self.global_step,
10000, 0.96)
opt = tf.train.AdagradOptimizer(learning_rate)
self.train_op = opt.apply_gradients(
zip(clipped_gradients, params),
global_step=self.global_step)
elif self.mode == "test":
def embedding_proj(inputs):
return input_layer(
tf.nn.embedding_lookup(self.embedding_matrix,
inputs))
inference_decoder = seq2seq.BeamSearchDecoder(cell=decoder_cell,
embedding=embedding_proj,
start_tokens=start_tokens,
end_token=end_token,
initial_state=decoder_initial_state,
beam_width=self.beam_depth,
output_layer=output_layer)
# For GreedyDecoder, return
# decoder_outputs_decode: BasicDecoderOutput instance
# namedtuple(rnn_outputs, sample_id)
# decoder_outputs_decode.rnn_output: [batch_size, max_time_step, num_decoder_symbols] if output_time_major=False
# [max_time_step, batch_size, num_decoder_symbols] if output_time_major=True
# decoder_outputs_decode.sample_id: [batch_size, max_time_step], tf.int32 if output_time_major=False
# [max_time_step, batch_size], tf.int32 if output_time_major=True
# For BeamSearchDecoder, return
# decoder_outputs_decode: FinalBeamSearchDecoderOutput instance
# namedtuple(predicted_ids, beam_search_decoder_output)
# decoder_outputs_decode.predicted_ids: [batch_size, max_time_step, beam_width] if output_time_major=False
# [max_time_step, batch_size, beam_width] if output_time_major=True
# decoder_outputs_decode.beam_search_decoder_output: BeamSearchDecoderOutput instance
# namedtuple(scores, predicted_ids, parent_ids)
with tf.device("/device:GPU:1"):
decoder_outputs, decoder_last_state, decoder_output_length = \
seq2seq.dynamic_decode(decoder=inference_decoder,
output_time_major=False,
swap_memory=True,
maximum_iterations=self.max_iter)
self.decoder_pred_test = decoder_outputs.predicted_ids
def __init__(self, params):
# Input variable
batch_size = params.batch_size
gen_length = params.gen_length
if infer == 1:
batch_size = 1
gen_length = 1
self.dropout_keep = tf.placeholder_with_default(tf.constant(1.0),
shape=None)
self.lr = tf.placeholder_with_default(tf.constant(0.01), shape=None)
self.x_word = tf.placeholder(tf.int32,
shape=(None, params.turn_num *
params.utc_length),
name='x_word')
self.x_api = tf.placeholder(tf.float32, shape=(None, 3), name='x_api')
self.y_word_in = tf.placeholder(tf.int32,
shape=(None, gen_length),
name='y_word')
self.y_word_out = tf.placeholder(tf.int32,
shape=(None, gen_length),
name='y_word')
self.y_len = tf.placeholder(tf.int32, shape=(None, ))
# Word embedding
x_embedding = tf.get_variable(
name='x_embedding', shape=[params.vocab_size, params.embed_size])
x_word_embedded = tf.nn.embedding_lookup(x_embedding, self.x_word)
y_embedding = tf.get_variable(
name='y_embedding', shape=[params.vocab_size, params.embed_size])
y_word_embedded = tf.nn.embedding_lookup(y_embedding, self.y_word_in)
# Extend x_api to concat with y_word_embedded
x_api = tf.expand_dims(self.x_api, 1)
x_api_extend = x_api
for i in range(gen_length - 1):
x_api_extend = tf.concat([x_api_extend, x_api], 1)
# y_word_embedded = tf.concat([y_word_embedded, x_api_extend], 2)
def single_cell(state_size): # define the cell of LSTM
return tf.contrib.rnn.BasicLSTMCell(state_size)
# Encoder
with tf.variable_scope('encoder'):
self.encoder_multi_cell = tf.contrib.rnn.MultiRNNCell([
single_cell(params.state_size) for _ in range(params.layer_num)
]) # multi-layer
self.encoder_outputs, self.encoder_state = tf.nn.dynamic_rnn(
self.encoder_multi_cell,
x_word_embedded,
sequence_length=[params.utc_length] * params.batch_size,
dtype=tf.float32,
scope='encoder')
with tf.variable_scope('decoder'):
self.decoder_multi_cell = tf.contrib.rnn.MultiRNNCell([
single_cell(params.state_size) for _ in range(params.layer_num)
]) # multi-layer
attn_mech = tf.contrib.seq2seq.BahdanauAttention(
num_units=params.state_size, # LuongAttention
memory=self.encoder_outputs,
name='attention_mechanic')
attn_cell = tf.contrib.seq2seq.DynamicAttentionWrapper(
self.decoder_multi_cell,
attention_mechanism=attn_mech,
attention_size=128,
name="attention_wrapper")
attn_zero = attn_cell.zero_state(batch_size=batch_size,
dtype=tf.float32)
init_state = tf.contrib.seq2seq.DynamicAttentionWrapperState(
cell_state=self.encoder_state, attention=attn_zero)
train_helper = tf.contrib.seq2seq.TrainingHelper(
inputs=y_word_embedded,
sequence_length=self.y_len,
time_major=False)
projection_layer = Dense(params.vocab_size)
decoder = tf.contrib.seq2seq.BasicDecoder(
cell=attn_cell, # attn_cell,
helper=train_helper, # A Helper instance
initial_state=init_state, # initial state of decoder
output_layer=projection_layer
) # instance of tf.layers.Layer, like Dense
# Perform dynamic decoding with decoder
self.decoder_outputs, self.decoder_state, _ = tf.contrib.seq2seq.dynamic_decode(
decoder=decoder)
self.w = tf.get_variable(
"softmax_w",
[params.vocab_size, params.vocab_size]) # weights for output
self.b = tf.get_variable("softmax_b", [params.vocab_size])
outputs = self.decoder_outputs[0]
# Loss
output = tf.reshape(outputs, [-1, params.vocab_size])
self.logits = tf.matmul(output, self.w) + self.b
self.probs = tf.nn.softmax(self.logits)
targets = tf.reshape(self.y_word_out, [-1])
weights = tf.ones_like(targets, dtype=tf.float32)
# print outputs
# print self.logits
# print targets
# print weights
loss = tf.contrib.legacy_seq2seq.sequence_loss([self.logits],
[targets], [weights])
self.cost = tf.reduce_sum(loss) / batch_size
optimizer = tf.train.AdamOptimizer(self.lr)
tvars = tf.trainable_variables()
grads = tf.gradients(self.cost, tvars)
grads, _ = tf.clip_by_global_norm(grads, params.grad_clip)
self.train_op = optimizer.apply_gradients(zip(grads, tvars))
def initialize_model(self):
# encoder_emb_layer = self.embedding_matrix
# decoder_emb_layer = self.embedding_matrix
INPUT_NUM_VOCAB = len(self.src_dictionary)
OUTPUT_NUM_VOCAB = len(self.src_dictionary)
tf.reset_default_graph()
self.encoder_input_seq = tf.placeholder(tf.int32, [None, None], name='encoder_input_seq')
self.encoder_seq_len = tf.placeholder(tf.int32, (None,), name='encoder_seq_len')
# Decoder placeholders
self.decoder_output_seq = tf.placeholder(tf.int32, [None, None], name='decoder_output_seq')
self.decoder_seq_len = tf.placeholder(tf.int32, (None,), name='decoder_seq_len')
max_decoder_seq_len = tf.reduce_max(self.decoder_seq_len, name='max_decoder_seq_len')
encoder_input_embedded = tf.nn.embedding_lookup(self.embedding_matrix, self.encoder_input_seq)
encoder_multi_cell = tf.nn.rnn_cell.BasicLSTMCell(self.RNN_STATE_DIM)
self.encoder_output, encoder_state = tf.nn.dynamic_rnn(encoder_multi_cell, encoder_input_embedded, sequence_length=self.encoder_seq_len, dtype=tf.float64)
decoder_raw_seq = self.decoder_output_seq[:, :-1]
go_prefixes = tf.fill([self.BATCH_SIZE, 1], self.src_dictionary[('<s>', 'None', 'None')])
decoder_input_seq = tf.concat([go_prefixes, decoder_raw_seq], 1)
decoder_input_embedded = tf.nn.embedding_lookup(self.embedding_matrix,
decoder_input_seq)
decoder_multi_cell = tf.nn.rnn_cell.BasicLSTMCell(self.RNN_STATE_DIM)
output_layer_kernel_initializer = tf.truncated_normal_initializer(mean=0.0, stddev=0.1)
output_layer = Dense(
OUTPUT_NUM_VOCAB,
kernel_initializer=output_layer_kernel_initializer
)
with tf.variable_scope("decode"):
training_helper = tf.contrib.seq2seq.TrainingHelper(
inputs=decoder_input_embedded,
sequence_length=[self.max_length for x in range(self.BATCH_SIZE)],
time_major=False
)
training_decoder = tf.contrib.seq2seq.BasicDecoder(
decoder_multi_cell,
training_helper,
encoder_state,
output_layer
)
training_decoder_output_seq, _, _ = tf.contrib.seq2seq.dynamic_decode(
training_decoder,
impute_finished=True,
maximum_iterations=self.max_length
)
with tf.variable_scope("decode", reuse=True):
start_tokens = tf.tile(
tf.constant([self.src_dictionary[('<s>', 'None', 'None')]],
dtype=tf.int32),
[self.BATCH_SIZE],
name='start_tokens')
# Helper for the inference process.
inference_helper = tf.contrib.seq2seq.GreedyEmbeddingHelper(
embedding=self.embedding_matrix,
start_tokens=start_tokens,
end_token=self.src_dictionary[('</s>', 'None', 'None')]
)
# Basic decoder
inference_decoder = tf.contrib.seq2seq.BasicDecoder(
decoder_multi_cell,
inference_helper,
encoder_state,
output_layer
)
# Perform dynamic decoding using the decoder
inference_decoder_output_seq, _, _ = tf.contrib.seq2seq.dynamic_decode(
inference_decoder,
impute_finished=True,
maximum_iterations=self.max_length
)
training_logits = tf.identity(training_decoder_output_seq.rnn_output, name='logits')
inference_logits = tf.identity(inference_decoder_output_seq.sample_id, name='predictions')
# Create the weights for sequence_loss
masks = tf.sequence_mask(
self.decoder_seq_len,
self.max_length,
dtype=tf.float64,
name='masks'
)
self.cost = tf.contrib.seq2seq.sequence_loss(
training_logits,
self.decoder_output_seq,
masks
)
optimizer = tf.train.AdamOptimizer(self.LEARNING_RATE)
self.train_pred = training_decoder_output_seq.sample_id
gradients = optimizer.compute_gradients(self.cost)
capped_gradients = [(tf.clip_by_value(grad, -5., 5.), var)
for grad, var in gradients if grad is not None]
self.train_op = optimizer.apply_gradients(capped_gradients)
def build_latent_space(self):
with tf.name_scope("latent_space"):
self.z_mean = Dense(self.latent_dim, name='z_mean')(self.h_N)
self.z_log_sigma = Dense(self.latent_dim, name='z_log_sigma')(self.h_N)
self.z_vector = tf.identity(self.sample_gaussian(), name='z_vector')
[
4.7, 3.2, 1.3, 0.2, 5.1, 3.5, 1.4, 0.2, 5.1, 3.5, 1.4, 0.2, 5.1, 3.5,
1.4, 0.2, 5.1, 3.5, 1.4, 0.2, 5.1, 3.5, 1.4, 0.2, 5.1, 3.5, 1.4, 0.2,
5.1, 3.5
],
[
4.6, 3.1, 1.5, 0.2, 5.1, 3.5, 1.4, 0.2, 5.1, 3.5, 1.4, 0.2, 5.1, 3.5,
1.4, 0.2, 5.1, 3.5, 1.4, 0.2, 5.1, 3.5, 1.4, 0.2, 5.1, 3.5, 1.4, 0.2,
5.1, 3.5
],
])
labels = np.array([0, 1, 0, 1])
print('------A. Training------')
model = Sequential()
layer1 = Dense(200, activation='relu', input_dim=4)
model.add(layer1)
layer2 = Dense(200, activation='relu')
model.add(layer2)
layer3 = Dense(3, activation='softmax')
model.add(layer3)
model.compile('adam', loss='categorical_crossentropy', metrics=['accuracy'])
# predefined multiclass dataset
train_output = model.fit(data, labels, batch_size=20, epochs=5)
print('---------------------')
print(train_output.history)
print('------B. Evaluation------')
# predefined eval dataset
for a in range(SIZE_RNN_LAYER):
cell = rnn.BasicLSTMCell(SIZE_RNN_STATE)
cell = rnn.DropoutWrapper(cell, output_keep_prob=keep_prob)
cell_decode.append(cell)
multi_rnn_decode = rnn.MultiRNNCell(cell_decode, state_is_tuple=True)
dec_cell = tf.contrib.seq2seq.AttentionWrapper(
cell=multi_rnn_decode,
attention_mechanism=attn_luong,
attention_layer_size=SIZE_ATTN,
name="attention_wrapper")
initial_state = dec_cell.zero_state(dtype=tf.float32, batch_size=batch_size)
initial_state = initial_state.clone(cell_state=state_enc)
output_layer = Dense(voc_size_kor, kernel_initializer=tf.truncated_normal_initializer(mean=0.0, stddev=0.1))
# train mode
with tf.variable_scope("decoder_layer"):
train_helper = tf.contrib.seq2seq.TrainingHelper(inputs=embed_dec,
sequence_length=dec_pad_len,
time_major=False)
train_decoder = tf.contrib.seq2seq.BasicDecoder(dec_cell, train_helper, initial_state, output_layer)
output_train_dec, state_train_dec, len_train_dec = tf.contrib.seq2seq.dynamic_decode(
decoder=train_decoder,
output_time_major=False,
impute_finished=True,
maximum_iterations=padded_kor_len)
# predict mode
def __init__(self, lstm_size, lstm_layers, source_vocab_size,
enc_embedding_size, tgt_word_to_int, dec_embedding_size,
tgt_max_length):
#-----------------------------------------------------------------------
# Placeholders
#-----------------------------------------------------------------------
self.inputs = tf.placeholder(tf.int32, [None, None], name='inputs')
self.targets = tf.placeholder(tf.int32, [None, None], name='targets')
self.batch_size = tf.placeholder(tf.int32, [], name='batch_size')
self.tgt_seq_length = tf.placeholder(tf.int32, [None],
name='tgt_seq_length')
self.src_seq_length = tf.placeholder(tf.int32, [None],
name='src_seq_length')
#-----------------------------------------------------------------------
# Encoder
#-----------------------------------------------------------------------
with tf.variable_scope('encoder'):
with tf.variable_scope('embedding'):
enc_embed = tf.contrib.layers.embed_sequence(
self.inputs, source_vocab_size, enc_embedding_size)
with tf.variable_scope('rnn'):
enc_cell = tf.contrib.rnn.MultiRNNCell(
[tf.contrib.rnn.BasicLSTMCell(lstm_size) \
for _ in range(lstm_layers)])
self.initial_state = enc_cell.zero_state(self.batch_size,
tf.float32)
_, self.enc_state = tf.nn.dynamic_rnn(
enc_cell,
enc_embed,
sequence_length=self.src_seq_length,
initial_state=self.initial_state)
#-----------------------------------------------------------------------
# Decoder
#-----------------------------------------------------------------------
target_vocab_size = len(tgt_word_to_int)
with tf.variable_scope('decoder'):
#-------------------------------------------------------------------
# Embedding
#-------------------------------------------------------------------
with tf.variable_scope('embedding'):
self.dec_embed = tf.Variable(
tf.random_uniform([target_vocab_size, dec_embedding_size]))
#-------------------------------------------------------------------
# Final classifier
#-------------------------------------------------------------------
with tf.variable_scope('classifier') as classifier_scope:
self.output_layer = Dense(target_vocab_size,
kernel_initializer = \
tf.truncated_normal_initializer(
mean = 0.0, stddev=0.1))
#-------------------------------------------------------------------
# RNN
#-------------------------------------------------------------------
with tf.variable_scope('rnn'):
self.dec_cell = tf.contrib.rnn.MultiRNNCell(
[tf.contrib.rnn.BasicLSTMCell(lstm_size) \
for _ in range(lstm_layers)])
#-------------------------------------------------------------------
# Inference decoder
#-------------------------------------------------------------------
with tf.variable_scope('decoder'):
start_tokens = tf.tile([tgt_word_to_int['<s>']],
[self.batch_size])
helper = seq2seq.GreedyEmbeddingHelper(self.dec_embed,
start_tokens,
tgt_word_to_int['</s>'])
decoder = seq2seq.BasicDecoder(self.dec_cell, helper,
self.enc_state,
self.output_layer)
outputs, _, _ = seq2seq.dynamic_decode(decoder,
impute_finished=\
True,
maximum_iterations=\
tgt_max_length)
self.outputs = tf.identity(outputs.sample_id, 'predictions')
def decoding_layer(phonem_dict, decoding_embedding_size, num_layers, rnn_size,
target_sequence_length, max_target_sequence_length,
encoder_state, decoder_input):
'''
构造Decoder层
参数：
- target_letter_to_int: target数据的映射表
- decoding_embedding_size: embed向量大小
- num_layers: 堆叠的RNN单元数量
- rnn_size: RNN单元的隐层结点数量
- target_sequence_length: target数据序列长度
- max_target_sequence_length: target数据序列最大长度
- encoder_state: encoder端编码的状态向量
- decoder_input: decoder端输入
'''
# 1. Embedding
target_vocab_size = len(phonem_dict)
decoder_embeddings = tf.Variable(
tf.random_uniform([target_vocab_size, decoding_embedding_size]))
decoder_embed_input = tf.nn.embedding_lookup(decoder_embeddings,
decoder_input)
# 构造Decoder中的RNN单元
def get_decoder_cell(rnn_size):
decoder_cell = tf.contrib.rnn.LSTMCell(
rnn_size,
initializer=tf.random_uniform_initializer(-0.1, 0.1, seed=2))
return decoder_cell
cell = tf.contrib.rnn.MultiRNNCell(
[get_decoder_cell(rnn_size) for _ in range(num_layers)])
# Output全连接层
# target_vocab_size定义了输出层的大小
output_layer = Dense(target_vocab_size,
kernel_initializer=tf.truncated_normal_initializer(
mean=0.1, stddev=0.1))
# 4. Training decoder
with tf.variable_scope("decode"):
training_helper = tf.contrib.seq2seq.TrainingHelper(
inputs=decoder_embed_input,
sequence_length=target_sequence_length,
time_major=False)
training_decoder = tf.contrib.seq2seq.BasicDecoder(
cell, training_helper, encoder_state, output_layer)
training_decoder_output, _, _ = tf.contrib.seq2seq.dynamic_decode(
training_decoder,
impute_finished=True,
maximum_iterations=max_target_sequence_length)
# 5. Predicting decoder
# 与training共享参数
with tf.variable_scope("decode", reuse=True):
# 创建一个常量tensor并复制为batch_size的大小
start_tokens = tf.tile(tf.constant([phonem_dict['_sos_']],
dtype=tf.int32),
[tf.shape(target_sequence_length)[0]],
name='start_token')
predicting_helper = tf.contrib.seq2seq.GreedyEmbeddingHelper(
decoder_embeddings, start_tokens, phonem_dict['_eos_'])
predicting_decoder = tf.contrib.seq2seq.BasicDecoder(
cell, predicting_helper, encoder_state, output_layer)
predicting_decoder_output, _, _ = \
tf.contrib.seq2seq.dynamic_decode(predicting_decoder,
impute_finished=True, maximum_iterations=max_target_sequence_length)
return training_decoder_output, predicting_decoder_output
def decoding_layer(target_letter_to_int, decoding_embedding_size, num_layers,
rnn_size, target_sequence_length,
max_target_sequence_length, enc_state, dec_input):
# 1. Decoder Embedding
target_vocab_size = len(target_letter_to_int)
dec_embeddings = tf.Variable(
tf.random_uniform([target_vocab_size, decoding_embedding_size]))
dec_embed_input = tf.nn.embedding_lookup(dec_embeddings, dec_input)
# 2. Construct the decoder cell
def make_cell(rnn_size):
dec_cell = tf.contrib.rnn.LSTMCell(
rnn_size,
initializer=tf.random_uniform_initializer(-0.1, 0.1, seed=2))
return dec_cell
dec_cell = tf.contrib.rnn.MultiRNNCell(
[make_cell(rnn_size) for _ in range(num_layers)])
# 3. Dense layer to translate the decoder's output at each time
# step into a choice from the target vocabulary
output_layer = Dense(target_vocab_size,
kernel_initializer=tf.truncated_normal_initializer(
mean=0.0, stddev=0.1))
# 4. Set up a training decoder and an inference decoder
# Training Decoder
with tf.variable_scope("decode"):
# Helper for the training process. Used by BasicDecoder to read inputs.
training_helper = tf.contrib.seq2seq.TrainingHelper(
inputs=dec_embed_input,
sequence_length=target_sequence_length,
time_major=False)
# Basic decoder
training_decoder = tf.contrib.seq2seq.BasicDecoder(
dec_cell, training_helper, enc_state, output_layer)
# Perform dynamic decoding using the decoder
training_decoder_output = tf.contrib.seq2seq.dynamic_decode(
training_decoder,
impute_finished=True,
maximum_iterations=max_target_sequence_length)[0]
# 5. Inference Decoder
# Reuses the same parameters trained by the training process
with tf.variable_scope("decode", reuse=True):
start_tokens = tf.tile(tf.constant([target_letter_to_int['<GO>']],
dtype=tf.int32), [batch_size],
name='start_tokens')
# Helper for the inference process.
inference_helper = tf.contrib.seq2seq.GreedyEmbeddingHelper(
dec_embeddings, start_tokens, target_letter_to_int['<EOS>'])
# Basic decoder
inference_decoder = tf.contrib.seq2seq.BasicDecoder(
dec_cell, inference_helper, enc_state, output_layer)
# Perform dynamic decoding using the decoder
inference_decoder_output = tf.contrib.seq2seq.dynamic_decode(
inference_decoder,
impute_finished=True,
maximum_iterations=max_target_sequence_length)[0]
return training_decoder_output, inference_decoder_output
def model(self):
# 将来替换为record input
inputs = tf.placeholder(dtype=tf.int32,
shape=(FLAGS.batch_size, FLAGS.en_max_length))
targets = tf.placeholder(dtype=tf.int32,
shape=(FLAGS.batch_size, FLAGS.zh_max_length))
start_tokens = tf.constant(0, dtype=tf.int32)
end_token = tf.constant(0, dtype=tf.int32)
en_len_sequence = tf.placeholder(dtype=tf.int32,
shape=FLAGS.batch_size)
zh_len_sequence = tf.placeholder(dtype=tf.int32,
shape=FLAGS.batch_size,
name='batch_seq_length')
en_embedding_matrix = tf.get_variable(
name='embedding_matrix',
shape=(FLAGS.en_vocab_size, FLAGS.en_embedded_size),
dtype=tf.float32,
# regularizer=tf.nn.l2_loss,
initializer=tf.truncated_normal_initializer(mean=0, stddev=0.01))
zh_embedding_matrix = tf.get_variable(
name='zh_embedding_matrix',
shape=(FLAGS.zh_vocab_size, FLAGS.zh_embedded_size),
dtype=tf.float32,
# regularizer=tf.nn.l2_loss,
initializer=tf.truncated_normal_initializer(mean=0, stddev=0.01))
tf.add_to_collection(tf.GraphKeys.LOSSES,
tf.nn.l2_loss(en_embedding_matrix))
tf.add_to_collection(tf.GraphKeys.LOSSES,
tf.nn.l2_loss(zh_embedding_matrix))
tf.summary.histogram('zh_embedding_matrix', zh_embedding_matrix)
tf.summary.histogram('en_embedding_matrix', en_embedding_matrix)
with tf.device('/cpu:0'):
embedded = tf.nn.embedding_lookup(en_embedding_matrix, inputs)
target_embedded = tf.nn.embedding_lookup(zh_embedding_matrix,
targets)
with tf.name_scope("encoder"):
cells_fw = [
tf.contrib.rnn.GRUCell(num) for num in config.encoder_fw_units
]
cells_bw = [
tf.contrib.rnn.GRUCell(num) for num in config.encoder_bw_units
]
outputs, states_fw, states_bw = \
tf.contrib.rnn.stack_bidirectional_dynamic_rnn(cells_fw,
cells_bw,
embedded,
dtype=tf.float32,
sequence_length=en_len_sequence)
dense_fw = tf.concat(states_fw, axis=1)
dense_bw = tf.concat(states_bw, axis=1)
states = tf.concat([dense_bw, dense_fw], axis=1)
tf.summary.histogram('encoder_state', states)
'''
external memory will add here
'''
with tf.name_scope("decoder"):
attention_m = \
tf.contrib.seq2seq.BahdanauAttention(
FLAGS.attention_size,
outputs,
en_len_sequence)
cell_out = [
tf.contrib.rnn.GRUCell(num) for num in config.out_cell_units
]
cell_attention = \
[tf.contrib.seq2seq.AttentionWrapper(
cell_out[i], attention_m) for i in range(len(config.out_cell_units))]
cells = tf.contrib.rnn.MultiRNNCell(cell_attention)
initial_state = cells.zero_state(dtype=tf.float32,
batch_size=FLAGS.batch_size)
initial_state = list(initial_state)
initial_state[0] = initial_state[0].clone(cell_state=states)
initial_state = tuple(initial_state)
if FLAGS.is_inference:
helper = tf.contrib.seq2seq.GreedyEmbeddingHelper(
zh_embedding_matrix, start_tokens, end_token)
else:
helper = tf.contrib.seq2seq.TrainingHelper(
target_embedded, zh_len_sequence)
dense = Dense(FLAGS.zh_vocab_size)
decoder = tf.contrib.seq2seq.BasicDecoder(cells, helper,
initial_state, dense)
logits, final_states, final_sequence_lengths = tf.contrib.seq2seq.dynamic_decode(
decoder)
weights = tf.constant(
1.0, shape=[FLAGS.batch_size, FLAGS.zh_max_length])
inference_losses = tf.contrib.seq2seq.sequence_loss(
logits.rnn_output, targets, weights)
tf.summary.scalar('inference_loss', inference_losses)
tf.add_to_collection(tf.GraphKeys.LOSSES, inference_losses)
losses = tf.add_n(tf.get_collection(tf.GraphKeys.LOSSES))
tf.summary.scalar('losses', losses)
eval = sequence_equal(logits.sample_id, targets)
tf.summary.scalar('eval', eval)
global_step = tf.train.get_or_create_global_step()
learning_rate = tf.train.exponential_decay(FLAGS.learning_rate,
global_step,
FLAGS.decay_step,
FLAGS.decay_rate)
tf.summary.scalar('learning_rate', learning_rate)
opt = tf.train.GradientDescentOptimizer(learning_rate)
grads_and_vars = opt.compute_gradients(losses)
clipped_grads_and_vars = tf.contrib.training.clip_gradient_norms(
grads_and_vars, FLAGS.max_gradient)
apply_grads_op = opt.apply_gradients(clipped_grads_and_vars,
global_step)
summary_op = tf.summary.merge_all()
if FLAGS.is_inference:
return logits.sample_id
elif FLAGS.is_train:
return [global_step, eval, losses, apply_grads_op, summary_op]
else:
return [global_step, eval, losses]