def __init__(self,
num_symbols,
num_embed_units,
num_units,
num_layers,
is_train,
vocab=None,
embed=None,
learning_rate=0.1,
learning_rate_decay_factor=0.95,
max_gradient_norm=5.0,
num_samples=512,
max_length=30,
use_lstm=True):
self.posts_1 = tf.placeholder(tf.string, shape=(None, None))
self.posts_2 = tf.placeholder(tf.string, shape=(None, None))
self.posts_3 = tf.placeholder(tf.string, shape=(None, None))
self.posts_4 = tf.placeholder(tf.string, shape=(None, None))
self.entity_1 = tf.placeholder(tf.string, shape=(None, None, None, 3))
self.entity_2 = tf.placeholder(tf.string, shape=(None, None, None, 3))
self.entity_3 = tf.placeholder(tf.string, shape=(None, None, None, 3))
self.entity_4 = tf.placeholder(tf.string, shape=(None, None, None, 3))
self.entity_mask_1 = tf.placeholder(tf.float32,
shape=(None, None, None))
self.entity_mask_2 = tf.placeholder(tf.float32,
shape=(None, None, None))
self.entity_mask_3 = tf.placeholder(tf.float32,
shape=(None, None, None))
self.entity_mask_4 = tf.placeholder(tf.float32,
shape=(None, None, None))
self.posts_length_1 = tf.placeholder(tf.int32, shape=(None))
self.posts_length_2 = tf.placeholder(tf.int32, shape=(None))
self.posts_length_3 = tf.placeholder(tf.int32, shape=(None))
self.posts_length_4 = tf.placeholder(tf.int32, shape=(None))
self.responses = tf.placeholder(tf.string, shape=(None, None))
self.responses_length = tf.placeholder(tf.int32, shape=(None))
self.epoch = tf.Variable(0, trainable=False, name='epoch')
self.epoch_add_op = self.epoch.assign(self.epoch + 1)
if is_train:
self.symbols = tf.Variable(vocab, trainable=False, name="symbols")
else:
self.symbols = tf.Variable(np.array(['.'] * num_symbols),
name="symbols")
self.symbol2index = HashTable(KeyValueTensorInitializer(
self.symbols,
tf.Variable(
np.array([i for i in range(num_symbols)], dtype=np.int32),
False)),
default_value=UNK_ID,
name="symbol2index")
self.posts_input_1 = self.symbol2index.lookup(self.posts_1)
self.posts_2_target = self.posts_2_embed = self.symbol2index.lookup(
self.posts_2)
self.posts_3_target = self.posts_3_embed = self.symbol2index.lookup(
self.posts_3)
self.posts_4_target = self.posts_4_embed = self.symbol2index.lookup(
self.posts_4)
self.responses_target = self.symbol2index.lookup(self.responses)
batch_size, decoder_len = tf.shape(self.posts_1)[0], tf.shape(
self.responses)[1]
self.posts_input_2 = tf.concat([
tf.ones([batch_size, 1], dtype=tf.int32) * GO_ID,
tf.split(self.posts_2_embed, [tf.shape(self.posts_2)[1] - 1, 1],
1)[0]
], 1)
self.posts_input_3 = tf.concat([
tf.ones([batch_size, 1], dtype=tf.int32) * GO_ID,
tf.split(self.posts_3_embed, [tf.shape(self.posts_3)[1] - 1, 1],
1)[0]
], 1)
self.posts_input_4 = tf.concat([
tf.ones([batch_size, 1], dtype=tf.int32) * GO_ID,
tf.split(self.posts_4_embed, [tf.shape(self.posts_4)[1] - 1, 1],
1)[0]
], 1)
self.responses_target = self.symbol2index.lookup(self.responses)
batch_size, decoder_len = tf.shape(self.posts_1)[0], tf.shape(
self.responses)[1]
self.responses_input = tf.concat([
tf.ones([batch_size, 1], dtype=tf.int32) * GO_ID,
tf.split(self.responses_target, [decoder_len - 1, 1], 1)[0]
], 1)
self.encoder_2_mask = tf.reshape(
tf.cumsum(tf.one_hot(self.posts_length_2 - 1,
tf.shape(self.posts_2)[1]),
reverse=True,
axis=1), [-1, tf.shape(self.posts_2)[1]])
self.encoder_3_mask = tf.reshape(
tf.cumsum(tf.one_hot(self.posts_length_3 - 1,
tf.shape(self.posts_3)[1]),
reverse=True,
axis=1), [-1, tf.shape(self.posts_3)[1]])
self.encoder_4_mask = tf.reshape(
tf.cumsum(tf.one_hot(self.posts_length_4 - 1,
tf.shape(self.posts_4)[1]),
reverse=True,
axis=1), [-1, tf.shape(self.posts_4)[1]])
self.decoder_mask = tf.reshape(
tf.cumsum(tf.one_hot(self.responses_length - 1, decoder_len),
reverse=True,
axis=1), [-1, decoder_len])
if embed is None:
self.embed = tf.get_variable('embed',
[num_symbols, num_embed_units],
tf.float32)
else:
self.embed = tf.get_variable('embed',
dtype=tf.float32,
initializer=embed)
self.encoder_input_1 = tf.nn.embedding_lookup(self.embed,
self.posts_input_1)
self.encoder_input_2 = tf.nn.embedding_lookup(self.embed,
self.posts_input_2)
self.encoder_input_3 = tf.nn.embedding_lookup(self.embed,
self.posts_input_3)
self.encoder_input_4 = tf.nn.embedding_lookup(self.embed,
self.posts_input_4)
self.decoder_input = tf.nn.embedding_lookup(self.embed,
self.responses_input)
entity_embedding_1 = tf.reshape(
tf.nn.embedding_lookup(self.embed,
self.symbol2index.lookup(self.entity_1)),
[
batch_size,
tf.shape(self.entity_1)[1],
tf.shape(self.entity_1)[2], 3 * num_embed_units
])
entity_embedding_2 = tf.reshape(
tf.nn.embedding_lookup(self.embed,
self.symbol2index.lookup(self.entity_2)),
[
batch_size,
tf.shape(self.entity_2)[1],
tf.shape(self.entity_2)[2], 3 * num_embed_units
])
entity_embedding_3 = tf.reshape(
tf.nn.embedding_lookup(self.embed,
self.symbol2index.lookup(self.entity_3)),
[
batch_size,
tf.shape(self.entity_3)[1],
tf.shape(self.entity_3)[2], 3 * num_embed_units
])
entity_embedding_4 = tf.reshape(
tf.nn.embedding_lookup(self.embed,
self.symbol2index.lookup(self.entity_4)),
[
batch_size,
tf.shape(self.entity_4)[1],
tf.shape(self.entity_4)[2], 3 * num_embed_units
])
head_1, relation_1, tail_1 = tf.split(entity_embedding_1,
[num_embed_units] * 3,
axis=3)
head_2, relation_2, tail_2 = tf.split(entity_embedding_2,
[num_embed_units] * 3,
axis=3)
head_3, relation_3, tail_3 = tf.split(entity_embedding_3,
[num_embed_units] * 3,
axis=3)
head_4, relation_4, tail_4 = tf.split(entity_embedding_4,
[num_embed_units] * 3,
axis=3)
with tf.variable_scope('graph_attention'):
#[batch_size, max_reponse_length, max_triple_num, 2*embed_units]
head_tail_1 = tf.concat([head_1, tail_1], axis=3)
#[batch_size, max_reponse_length, max_triple_num, embed_units]
head_tail_transformed_1 = tf.layers.dense(
head_tail_1,
num_embed_units,
activation=tf.tanh,
name='head_tail_transform')
#[batch_size, max_reponse_length, max_triple_num, embed_units]
relation_transformed_1 = tf.layers.dense(relation_1,
num_embed_units,
name='relation_transform')
#[batch_size, max_reponse_length, max_triple_num]
e_weight_1 = tf.reduce_sum(relation_transformed_1 *
head_tail_transformed_1,
axis=3)
#[batch_size, max_reponse_length, max_triple_num]
alpha_weight_1 = tf.nn.softmax(e_weight_1)
#[batch_size, max_reponse_length, embed_units]
graph_embed_1 = tf.reduce_sum(
tf.expand_dims(alpha_weight_1, 3) *
(tf.expand_dims(self.entity_mask_1, 3) * head_tail_1),
axis=2)
with tf.variable_scope('graph_attention', reuse=True):
head_tail_2 = tf.concat([head_2, tail_2], axis=3)
head_tail_transformed_2 = tf.layers.dense(
head_tail_2,
num_embed_units,
activation=tf.tanh,
name='head_tail_transform')
relation_transformed_2 = tf.layers.dense(relation_2,
num_embed_units,
name='relation_transform')
e_weight_2 = tf.reduce_sum(relation_transformed_2 *
head_tail_transformed_2,
axis=3)
alpha_weight_2 = tf.nn.softmax(e_weight_2)
graph_embed_2 = tf.reduce_sum(
tf.expand_dims(alpha_weight_2, 3) *
(tf.expand_dims(self.entity_mask_2, 3) * head_tail_2),
axis=2)
with tf.variable_scope('graph_attention', reuse=True):
head_tail_3 = tf.concat([head_3, tail_3], axis=3)
head_tail_transformed_3 = tf.layers.dense(
head_tail_3,
num_embed_units,
activation=tf.tanh,
name='head_tail_transform')
relation_transformed_3 = tf.layers.dense(relation_3,
num_embed_units,
name='relation_transform')
e_weight_3 = tf.reduce_sum(relation_transformed_3 *
head_tail_transformed_3,
axis=3)
alpha_weight_3 = tf.nn.softmax(e_weight_3)
graph_embed_3 = tf.reduce_sum(
tf.expand_dims(alpha_weight_3, 3) *
(tf.expand_dims(self.entity_mask_3, 3) * head_tail_3),
axis=2)
with tf.variable_scope('graph_attention', reuse=True):
head_tail_4 = tf.concat([head_4, tail_4], axis=3)
head_tail_transformed_4 = tf.layers.dense(
head_tail_4,
num_embed_units,
activation=tf.tanh,
name='head_tail_transform')
relation_transformed_4 = tf.layers.dense(relation_4,
num_embed_units,
name='relation_transform')
e_weight_4 = tf.reduce_sum(relation_transformed_4 *
head_tail_transformed_4,
axis=3)
alpha_weight_4 = tf.nn.softmax(e_weight_4)
graph_embed_4 = tf.reduce_sum(
tf.expand_dims(alpha_weight_4, 3) *
(tf.expand_dims(self.entity_mask_4, 3) * head_tail_4),
axis=2)
if use_lstm:
cell = MultiRNNCell([LSTMCell(num_units)] * num_layers)
else:
cell = MultiRNNCell([GRUCell(num_units)] * num_layers)
output_fn, sampled_sequence_loss = output_projection_layer(
num_units, num_symbols, num_samples)
encoder_output_1, encoder_state_1 = dynamic_rnn(cell,
self.encoder_input_1,
self.posts_length_1,
dtype=tf.float32,
scope="encoder")
attention_keys_1, attention_values_1, attention_score_fn_1, attention_construct_fn_1 \
= attention_decoder_fn.prepare_attention(graph_embed_1, encoder_output_1, 'luong', num_units)
decoder_fn_train_1 = attention_decoder_fn.attention_decoder_fn_train(
encoder_state_1,
attention_keys_1,
attention_values_1,
attention_score_fn_1,
attention_construct_fn_1,
max_length=tf.reduce_max(self.posts_length_2))
encoder_output_2, encoder_state_2, alignments_ta_2 = dynamic_rnn_decoder(
cell,
decoder_fn_train_1,
self.encoder_input_2,
self.posts_length_2,
scope="decoder")
self.alignments_2 = tf.transpose(alignments_ta_2.stack(),
perm=[1, 0, 2])
self.decoder_loss_2 = sampled_sequence_loss(encoder_output_2,
self.posts_2_target,
self.encoder_2_mask)
with variable_scope.variable_scope('', reuse=True):
attention_keys_2, attention_values_2, attention_score_fn_2, attention_construct_fn_2 \
= attention_decoder_fn.prepare_attention(graph_embed_2, encoder_output_2, 'luong', num_units)
decoder_fn_train_2 = attention_decoder_fn.attention_decoder_fn_train(
encoder_state_2,
attention_keys_2,
attention_values_2,
attention_score_fn_2,
attention_construct_fn_2,
max_length=tf.reduce_max(self.posts_length_3))
encoder_output_3, encoder_state_3, alignments_ta_3 = dynamic_rnn_decoder(
cell,
decoder_fn_train_2,
self.encoder_input_3,
self.posts_length_3,
scope="decoder")
self.alignments_3 = tf.transpose(alignments_ta_3.stack(),
perm=[1, 0, 2])
self.decoder_loss_3 = sampled_sequence_loss(
encoder_output_3, self.posts_3_target, self.encoder_3_mask)
attention_keys_3, attention_values_3, attention_score_fn_3, attention_construct_fn_3 \
= attention_decoder_fn.prepare_attention(graph_embed_3, encoder_output_3, 'luong', num_units)
decoder_fn_train_3 = attention_decoder_fn.attention_decoder_fn_train(
encoder_state_3,
attention_keys_3,
attention_values_3,
attention_score_fn_3,
attention_construct_fn_3,
max_length=tf.reduce_max(self.posts_length_4))
encoder_output_4, encoder_state_4, alignments_ta_4 = dynamic_rnn_decoder(
cell,
decoder_fn_train_3,
self.encoder_input_4,
self.posts_length_4,
scope="decoder")
self.alignments_4 = tf.transpose(alignments_ta_4.stack(),
perm=[1, 0, 2])
self.decoder_loss_4 = sampled_sequence_loss(
encoder_output_4, self.posts_4_target, self.encoder_4_mask)
attention_keys, attention_values, attention_score_fn, attention_construct_fn \
= attention_decoder_fn.prepare_attention(graph_embed_4, encoder_output_4, 'luong', num_units)
if is_train:
with variable_scope.variable_scope('', reuse=True):
decoder_fn_train = attention_decoder_fn.attention_decoder_fn_train(
encoder_state_4,
attention_keys,
attention_values,
attention_score_fn,
attention_construct_fn,
max_length=tf.reduce_max(self.responses_length))
self.decoder_output, _, alignments_ta = dynamic_rnn_decoder(
cell,
decoder_fn_train,
self.decoder_input,
self.responses_length,
scope="decoder")
self.alignments = tf.transpose(alignments_ta.stack(),
perm=[1, 0, 2])
self.decoder_loss = sampled_sequence_loss(
self.decoder_output, self.responses_target,
self.decoder_mask)
self.params = tf.trainable_variables()
self.learning_rate = tf.Variable(float(learning_rate),
trainable=False,
dtype=tf.float32)
self.learning_rate_decay_op = self.learning_rate.assign(
self.learning_rate * learning_rate_decay_factor)
self.global_step = tf.Variable(0, trainable=False)
#opt = tf.train.GradientDescentOptimizer(self.learning_rate)
opt = tf.train.MomentumOptimizer(self.learning_rate, 0.9)
gradients = tf.gradients(
self.decoder_loss + self.decoder_loss_2 + self.decoder_loss_3 +
self.decoder_loss_4, self.params)
clipped_gradients, self.gradient_norm = tf.clip_by_global_norm(
gradients, max_gradient_norm)
self.update = opt.apply_gradients(zip(clipped_gradients,
self.params),
global_step=self.global_step)
else:
with variable_scope.variable_scope('', reuse=True):
decoder_fn_inference = attention_decoder_fn.attention_decoder_fn_inference(
output_fn, encoder_state_4, attention_keys,
attention_values, attention_score_fn,
attention_construct_fn, self.embed, GO_ID, EOS_ID,
max_length, num_symbols)
self.decoder_distribution, _, alignments_ta = dynamic_rnn_decoder(
cell, decoder_fn_inference, scope="decoder")
output_len = tf.shape(self.decoder_distribution)[1]
self.alignments = tf.transpose(
alignments_ta.gather(tf.range(output_len)), [1, 0, 2])
self.generation_index = tf.argmax(
tf.split(self.decoder_distribution, [2, num_symbols - 2],
2)[1], 2) + 2 # for removing UNK
self.generation = tf.nn.embedding_lookup(self.symbols,
self.generation_index,
name="generation")
self.params = tf.trainable_variables()
self.saver = tf.train.Saver(tf.global_variables(),
write_version=tf.train.SaverDef.V2,
max_to_keep=10,
pad_step_number=True,
keep_checkpoint_every_n_hours=1.0)
def __init__(self,
num_symbols,
num_embed_units,
num_units,
num_layers,
vocab=None,
embed=None,
name_scope=None,
learning_rate=0.001,
learning_rate_decay_factor=0.95,
max_gradient_norm=5,
num_samples=512,
max_length=30):
self.posts = tf.placeholder(tf.string, shape=[None,
None]) # batch * len
self.posts_length = tf.placeholder(tf.int32, shape=[None]) # batch
self.responses = tf.placeholder(tf.string, shape=[None,
None]) # batch*len
self.responses_length = tf.placeholder(tf.int32, shape=[None]) # batch
self.weight = tf.placeholder(tf.float32, shape=[None]) # batch
# build the vocab table (string to index)
self.symbols = tf.Variable(vocab, trainable=False, name="symbols")
self.symbol2index = HashTable(KeyValueTensorInitializer(
self.symbols,
tf.Variable(
np.array([i for i in range(num_symbols)], dtype=np.int32),
False)),
default_value=UNK_ID,
name="symbol2index")
# build the embedding table (index to vector)
if embed is None:
# initialize the embedding randomly
self.embed = tf.get_variable('embed',
[num_symbols, num_embed_units],
tf.float32)
else:
# initialize the embedding by pre-trained word vectors
self.embed = tf.get_variable('embed',
dtype=tf.float32,
initializer=embed)
self.posts_input = self.symbol2index.lookup(
self.posts) # batch * utter_len
self.encoder_input = tf.nn.embedding_lookup(
self.embed, self.posts_input) # batch * utter_len * embed_unit
self.responses_target = self.symbol2index.lookup(
self.responses) # batch, len
batch_size, decoder_len = tf.shape(self.responses)[0], tf.shape(
self.responses)[1]
self.responses_input = tf.concat([
tf.ones([batch_size, 1], dtype=tf.int32) * GO_ID,
tf.split(self.responses_target, [decoder_len - 1, 1], 1)[0]
], 1) # batch, len
self.decoder_mask = tf.reshape(
tf.cumsum(tf.one_hot(self.responses_length - 1, decoder_len),
reverse=True,
axis=1), [-1, decoder_len]) # batch, len
self.decoder_input = tf.nn.embedding_lookup(self.embed,
self.responses_input)
# Construct multi-layer GRU cells for encoder and decoder
cell_enc = MultiRNNCell(
[GRUCell(num_units) for _ in range(num_layers)])
cell_dec = MultiRNNCell(
[GRUCell(num_units) for _ in range(num_layers)])
# Encode the post sequence
encoder_output, encoder_state = tf.nn.dynamic_rnn(cell_enc,
self.encoder_input,
self.posts_length,
dtype=tf.float32,
scope="encoder")
output_fn, sampled_sequence_loss = output_projection_layer(
num_units, num_symbols, num_samples)
attention_keys, attention_values, attention_score_fn, attention_construct_fn \
= my_attention_decoder_fn.prepare_attention(encoder_output, 'bahdanau', num_units)
# Decode the response sequence (Training)
with variable_scope.variable_scope('decoder'):
decoder_fn_train = my_attention_decoder_fn.attention_decoder_fn_train(
encoder_state, attention_keys, attention_values,
attention_score_fn, attention_construct_fn)
self.decoder_output, _, _ = my_seq2seq.dynamic_rnn_decoder(
cell_dec,
decoder_fn_train,
self.decoder_input,
self.responses_length,
scope='decoder_rnn')
self.decoder_loss = my_loss.sequence_loss(
self.decoder_output,
self.responses_target,
self.decoder_mask,
softmax_loss_function=sampled_sequence_loss)
self.weighted_decoder_loss = self.decoder_loss * self.weight
attention_keys_infer, attention_values_infer, attention_score_fn_infer, attention_construct_fn_infer \
= my_attention_decoder_fn.prepare_attention(encoder_output, 'bahdanau', num_units, reuse = True)
# Decode the response sequence (Inference)
with variable_scope.variable_scope('decoder', reuse=True):
decoder_fn_inference = my_attention_decoder_fn.attention_decoder_fn_inference(
output_fn, encoder_state, attention_keys_infer,
attention_values_infer, attention_score_fn_infer,
attention_construct_fn_infer, self.embed, GO_ID, EOS_ID,
max_length, num_symbols)
self.decoder_distribution, _, _ = my_seq2seq.dynamic_rnn_decoder(
cell_dec, decoder_fn_inference, scope='decoder_rnn')
self.generation_index = tf.argmax(
tf.split(self.decoder_distribution, [2, num_symbols - 2],
2)[1], 2) + 2 # for removing UNK
self.generation = tf.nn.embedding_lookup(self.symbols,
self.generation_index)
self.params = [
k for k in tf.trainable_variables() if name_scope in k.name
]
# initialize the training process
self.learning_rate = tf.Variable(float(learning_rate),
trainable=False,
dtype=tf.float32)
self.learning_rate_decay_op = self.learning_rate.assign(
self.learning_rate * learning_rate_decay_factor)
self.global_step = tf.Variable(0, trainable=False)
self.adv_global_step = tf.Variable(0, trainable=False)
# calculate the gradient of parameters
self.cost = tf.reduce_mean(self.weighted_decoder_loss)
self.unweighted_cost = tf.reduce_mean(self.decoder_loss)
opt = tf.train.AdamOptimizer(self.learning_rate)
gradients = tf.gradients(self.cost, self.params)
clipped_gradients, self.gradient_norm = tf.clip_by_global_norm(
gradients, max_gradient_norm)
self.update = opt.apply_gradients(zip(clipped_gradients, self.params),
global_step=self.global_step)
all_variables = [
k for k in tf.global_variables() if name_scope in k.name
]
self.saver = tf.train.Saver(all_variables,
write_version=tf.train.SaverDef.V2,
max_to_keep=5,
pad_step_number=True,
keep_checkpoint_every_n_hours=1.0)
self.adv_saver = tf.train.Saver(all_variables,
write_version=tf.train.SaverDef.V2,
max_to_keep=5,
pad_step_number=True,
keep_checkpoint_every_n_hours=1.0)
def __init__(self, sess, config, api, log_dir, forward, scope=None):
self.vocab = api.vocab
self.rev_vocab = api.rev_vocab
self.vocab_size = len(self.vocab)
self.topic_vocab = api.topic_vocab
self.topic_vocab_size = len(self.topic_vocab)
self.da_vocab = api.dialog_act_vocab
self.da_vocab_size = len(self.da_vocab)
self.sess = sess
self.scope = scope
self.pad_id = self.rev_vocab["<pad>"]
self.sos_id = self.rev_vocab["<s>"]
self.eos_id = self.rev_vocab["</s>"]
self.unk_id = self.rev_vocab["<unk>"]
self.context_cell_size = config.cxt_cell_size
self.sent_cell_size = config.sent_cell_size
self.dec_cell_size = config.dec_cell_size
self.latent_size = config.latent_size
with tf.name_scope("io"):
self.input_contexts = tf.placeholder(dtype=tf.string,
shape=(None, None, None),
name="dialog_context")
self.context_lens = tf.placeholder(dtype=tf.int32,
shape=(None, ),
name="context_lens")
self.topics = tf.placeholder(dtype=tf.int32,
shape=(None, ),
name="topics")
self.output_tokens = tf.placeholder(dtype=tf.string,
shape=(None, None, None),
name="output_token")
self.output_lens = tf.placeholder(dtype=tf.int32,
shape=(None, None),
name="output_lens")
self.learning_rate = tf.Variable(float(config.init_lr),
trainable=False,
name="learning_rate")
self.learning_rate_decay_op = self.learning_rate.assign(
tf.multiply(self.learning_rate, config.lr_decay))
self.global_t = tf.placeholder(dtype=tf.int32, name="global_t")
self.use_prior = tf.placeholder(dtype=tf.bool, name="use_prior")
batch_size = tf.shape(self.input_contexts)[0]
max_dialog_len = tf.shape(self.input_contexts)[1]
max_out_len = tf.shape(self.output_tokens)[2]
with tf.variable_scope("tokenization"):
self.symbols = tf.Variable(self.vocab,
trainable=False,
name="symbols")
self.symbol2index = HashTable(KeyValueTensorInitializer(
self.symbols,
tf.Variable(
np.array([i for i in range(self.vocab_size)],
dtype=np.int32), False)),
default_value=self.unk_id,
name="symbol2index")
self.contexts = self.symbol2index.lookup(self.input_contexts)
self.responses_target = self.symbol2index.lookup(
self.output_tokens)
with tf.variable_scope("topic_embedding"):
t_embedding = tf.get_variable(
"embedding", [self.topic_vocab_size, config.topic_embed_size],
dtype=tf.float32)
topic_embedding = tf.nn.embedding_lookup(t_embedding, self.topics)
# [batch_size, topic_embed_size]
with tf.variable_scope("word_embedding"):
self.embedding = tf.get_variable(
"embedding", [self.vocab_size, config.embed_size],
dtype=tf.float32)
embedding_mask = tf.constant(
[0 if i == 0 else 1 for i in range(self.vocab_size)],
dtype=tf.float32,
shape=[self.vocab_size, 1])
embedding = self.embedding * embedding_mask
input_embedding = tf.nn.embedding_lookup(
embedding, tf.reshape(self.contexts, [-1]))
input_embedding = tf.reshape(
input_embedding,
[batch_size * max_dialog_len, -1, config.embed_size])
output_embedding = tf.nn.embedding_lookup(
embedding, tf.reshape(self.responses_target, [-1]))
output_embedding = tf.reshape(
output_embedding,
[batch_size * max_dialog_len, -1, config.embed_size])
with tf.variable_scope("uttrance_encoder"):
if config.sent_type == "rnn":
sent_cell = self.create_rnn_cell(self.sent_cell_size)
input_embedding, sent_size = get_rnn_encode(input_embedding,
sent_cell,
scope="sent_rnn")
output_embedding, _ = get_rnn_encode(output_embedding,
sent_cell,
tf.reshape(
self.output_lens,
[-1]),
scope="sent_rnn",
reuse=True)
elif config.sent_type == "bi_rnn":
fwd_sent_cell = self.create_rnn_cell(self.sent_cell_size)
bwd_sent_cell = self.create_rnn_cell(self.sent_cell_size)
input_embedding, sent_size = get_bi_rnn_encode(
input_embedding,
fwd_sent_cell,
bwd_sent_cell,
scope="sent_bi_rnn")
output_embedding, _ = get_bi_rnn_encode(output_embedding,
fwd_sent_cell,
bwd_sent_cell,
tf.reshape(
self.output_lens,
[-1]),
scope="sent_bi_rnn",
reuse=True)
else:
raise ValueError(
"Unknown sent_type. Must be one of [rnn, bi_rnn]")
input_embedding = tf.reshape(
input_embedding, [batch_size, max_dialog_len, sent_size])
if config.keep_prob < 1.0:
input_embedding = tf.nn.dropout(input_embedding,
config.keep_prob)
output_embedding = tf.reshape(
output_embedding, [batch_size, max_dialog_len, sent_size])
with tf.variable_scope("context_encoder"):
enc_cell = self.create_rnn_cell(self.context_cell_size)
cxt_outputs, _ = tf.nn.dynamic_rnn(
enc_cell,
input_embedding,
dtype=tf.float32,
sequence_length=self.context_lens)
# [batch_size, max_dialog_len, context_cell_size]
tile_topic_embedding = tf.reshape(
tf.tile(topic_embedding, [1, max_dialog_len]),
[batch_size, max_dialog_len, config.topic_embed_size])
cond_embedding = tf.concat([tile_topic_embedding, cxt_outputs], -1)
# [batch_size, max_dialog_len, context_cell_size + topic_embed_size]
with tf.variable_scope("posterior_network"):
recog_input = tf.concat([cond_embedding, output_embedding], -1)
post_sample, recog_mu_1, recog_logvar_1, recog_mu_2, recog_logvar_2 = self.hierarchical_inference_net(
recog_input)
with tf.variable_scope("prior_network"):
prior_input = cond_embedding
prior_sample, prior_mu_1, prior_logvar_1, prior_mu_2, prior_logvar_2 = self.hierarchical_inference_net(
prior_input)
latent_sample = tf.cond(self.use_prior, lambda: prior_sample,
lambda: post_sample)
with tf.variable_scope("decoder"):
dec_inputs = tf.concat([cond_embedding, latent_sample], -1)
dec_inputs_dim = config.latent_size + config.topic_embed_size + self.context_cell_size
dec_inputs = tf.reshape(
dec_inputs, [batch_size * max_dialog_len, dec_inputs_dim])
dec_init_state = tf.contrib.layers.fully_connected(
dec_inputs,
self.dec_cell_size,
activation_fn=None,
scope="init_state")
dec_cell = self.create_rnn_cell(self.dec_cell_size)
output_fn, sampled_sequence_loss = output_projection_layer(
self.dec_cell_size, self.vocab_size)
decoder_fn_train = decoder_fn.simple_decoder_fn_train(
dec_init_state, dec_inputs)
decoder_fn_inference = decoder_fn.simple_decoder_fn_inference(
output_fn, dec_init_state, dec_inputs, embedding, self.sos_id,
self.eos_id, max_out_len * 2, self.vocab_size)
if forward:
dec_outs, _, final_context_state = dynamic_rnn_decoder(
dec_cell, decoder_fn_inference, scope="decoder")
else:
dec_input_embedding = tf.nn.embedding_lookup(
embedding, tf.reshape(self.responses_target, [-1]))
dec_input_embedding = tf.reshape(
dec_input_embedding,
[batch_size * max_dialog_len, -1, config.embed_size])
dec_input_embedding = dec_input_embedding[:, 0:-1, :]
dec_seq_lens = tf.reshape(self.output_lens, [-1]) - 1
if config.dec_keep_prob < 1.0:
keep_mask = tf.less_equal(
tf.random_uniform(
(batch_size * max_dialog_len, max_out_len - 1),
minval=0.0,
maxval=1.0), config.dec_keep_prob)
keep_mask = tf.expand_dims(tf.to_float(keep_mask), 2)
dec_input_embedding = dec_input_embedding * keep_mask
dec_input_embedding = tf.reshape(
dec_input_embedding,
[-1, max_out_len - 1, config.embed_size])
dec_outs, _, final_context_state = dynamic_rnn_decoder(
dec_cell,
decoder_fn_train,
dec_input_embedding,
dec_seq_lens,
scope="decoder")
reshape_target = tf.reshape(self.responses_target,
[batch_size * max_dialog_len, -1])
labels = reshape_target[:, 1:]
label_mask = tf.to_float(tf.sign(labels))
local_loss = sampled_sequence_loss(dec_outs, labels,
label_mask)
if final_context_state is not None:
final_context_state = final_context_state[:, 0:tf.
shape(dec_outs)[1]]
mask = tf.to_int32(tf.sign(tf.reduce_max(dec_outs, axis=2)))
dec_out_words = tf.multiply(
tf.reverse(final_context_state, axis=[1]), mask)
else:
dec_out_words = tf.argmax(dec_outs, 2)
self.dec_out_words = tf.reshape(
dec_out_words, [batch_size, max_dialog_len, -1])[:, -1, :]
if not forward:
with tf.variable_scope("loss"):
self.avg_rc_loss = tf.reduce_mean(local_loss)
self.rc_ppl = tf.reduce_sum(local_loss)
self.total_word = tf.reduce_sum(label_mask)
new_recog_mu_2 = tf.reshape(recog_mu_2,
[-1, config.latent_size])
new_recog_logvar_2 = tf.reshape(recog_logvar_2,
[-1, config.latent_size])
new_prior_mu_1 = tf.reshape(prior_mu_1,
[-1, config.latent_size])
new_prior_logvar_1 = tf.reshape(prior_logvar_1,
[-1, config.latent_size])
new_recog_mu_1 = tf.reshape(recog_mu_1,
[-1, config.latent_size])
new_recog_logvar_1 = tf.reshape(recog_logvar_1,
[-1, config.latent_size])
new_prior_mu_2 = tf.reshape(prior_mu_2,
[-1, config.latent_size])
new_prior_logvar_2 = tf.reshape(prior_logvar_2,
[-1, config.latent_size])
kld_1 = gaussian_kld(new_recog_mu_2, new_recog_logvar_2,
new_prior_mu_1, new_prior_logvar_1)
kld_2 = gaussian_kld(new_recog_mu_1, new_recog_logvar_1,
new_prior_mu_2, new_prior_logvar_2)
kld = kld_1 + kld_2
self.avg_kld = tf.reduce_mean(kld)
if log_dir is not None:
self.kl_w = tf.minimum(
tf.to_float(self.global_t) / config.full_kl_step, 1.0)
else:
self.kl_w = tf.constant(1.0)
aug_elbo = self.elbo = self.avg_rc_loss + self.kl_w * self.avg_kld
tf.summary.scalar("rc_loss", self.avg_rc_loss)
tf.summary.scalar("elbo", self.elbo)
tf.summary.scalar("kld", self.avg_kld)
self.summary_op = tf.summary.merge_all()
"""
self.log_p_z = norm_log_liklihood(latent_sample, prior_mu, prior_logvar)
self.log_q_z_xy = norm_log_liklihood(latent_sample, recog_mu, recog_logvar)
self.est_marginal = tf.reduce_mean(- self.log_p_z + self.log_q_z_xy)
"""
self.optimize(sess, config, aug_elbo, log_dir)
self.saver = tf.train.Saver(tf.global_variables(),
write_version=tf.train.SaverDef.V2)
def __init__(self,
num_symbols,
num_qwords, #modify
num_embed_units,
num_units,
num_layers,
is_train,
vocab=None,
embed=None,
question_data=True,
learning_rate=0.5,
learning_rate_decay_factor=0.95,
max_gradient_norm=5.0,
num_samples=512,
max_length=30,
use_lstm=False):
self.posts = tf.placeholder(tf.string, shape=(None, None)) # batch*len
self.posts_length = tf.placeholder(tf.int32, shape=(None)) # batch
self.responses = tf.placeholder(tf.string, shape=(None, None)) # batch*len
self.responses_length = tf.placeholder(tf.int32, shape=(None)) # batch
self.keyword_tensor = tf.placeholder(tf.float32, shape=(None, 3, None)) #(batch * len) * 3 * numsymbol
self.word_type = tf.placeholder(tf.int32, shape=(None)) #(batch * len)
# build the vocab table (string to index)
if is_train:
self.symbols = tf.Variable(vocab, trainable=False, name="symbols")
else:
self.symbols = tf.Variable(np.array(['.']*num_symbols), name="symbols")
self.symbol2index = HashTable(KeyValueTensorInitializer(self.symbols,
tf.Variable(np.array([i for i in range(num_symbols)], dtype=np.int32), False)),
default_value=UNK_ID, name="symbol2index")
self.posts_input = self.symbol2index.lookup(self.posts) # batch*len
self.responses_target = self.symbol2index.lookup(self.responses) #batch*len
batch_size, decoder_len = tf.shape(self.responses)[0], tf.shape(self.responses)[1]
self.responses_input = tf.concat([tf.ones([batch_size, 1], dtype=tf.int32)*GO_ID,
tf.split(self.responses_target, [decoder_len-1, 1], 1)[0]], 1) # batch*len
#delete the last column of responses_target) and add 'GO at the front of it.
self.decoder_mask = tf.reshape(tf.cumsum(tf.one_hot(self.responses_length-1,
decoder_len), reverse=True, axis=1), [-1, decoder_len]) # bacth * len
print "embedding..."
# build the embedding table (index to vector)
if embed is None:
# initialize the embedding randomly
self.embed = tf.get_variable('embed', [num_symbols, num_embed_units], tf.float32)
else:
print len(vocab), len(embed), len(embed[0])
print embed
# initialize the embedding by pre-trained word vectors
self.embed = tf.get_variable('embed', dtype=tf.float32, initializer=embed)
self.encoder_input = tf.nn.embedding_lookup(self.embed, self.posts_input) #batch*len*unit
self.decoder_input = tf.nn.embedding_lookup(self.embed, self.responses_input)
print "embedding finished"
if use_lstm:
cell = MultiRNNCell([LSTMCell(num_units)] * num_layers)
else:
cell = MultiRNNCell([GRUCell(num_units)] * num_layers)
# rnn encoder
encoder_output, encoder_state = dynamic_rnn(cell, self.encoder_input,
self.posts_length, dtype=tf.float32, scope="encoder")
# get output projection function
output_fn, sampled_sequence_loss = output_projection_layer(num_units,
num_symbols, num_qwords, num_samples, question_data)
print "encoder_output.shape:", encoder_output.get_shape()
# get attention function
attention_keys, attention_values, attention_score_fn, attention_construct_fn \
= attention_decoder_fn.prepare_attention(encoder_output, 'luong', num_units)
# get decoding loop function
decoder_fn_train = attention_decoder_fn.attention_decoder_fn_train(encoder_state,
attention_keys, attention_values, attention_score_fn, attention_construct_fn)
decoder_fn_inference = attention_decoder_fn.attention_decoder_fn_inference(output_fn,
self.keyword_tensor,
encoder_state, attention_keys, attention_values, attention_score_fn,
attention_construct_fn, self.embed, GO_ID, EOS_ID, max_length, num_symbols)
if is_train:
# rnn decoder
self.decoder_output, _, _ = dynamic_rnn_decoder(cell, decoder_fn_train,
self.decoder_input, self.responses_length, scope="decoder")
# calculate the loss of decoder
# self.decoder_output = tf.Print(self.decoder_output, [self.decoder_output])
self.decoder_loss, self.log_perplexity = sampled_sequence_loss(self.decoder_output,
self.responses_target, self.decoder_mask, self.keyword_tensor, self.word_type)
# building graph finished and get all parameters
self.params = tf.trainable_variables()
for item in tf.trainable_variables():
print item.name, item.get_shape()
# initialize the training process
self.learning_rate = tf.Variable(float(learning_rate), trainable=False,
dtype=tf.float32)
self.learning_rate_decay_op = self.learning_rate.assign(
self.learning_rate * learning_rate_decay_factor)
self.global_step = tf.Variable(0, trainable=False)
# calculate the gradient of parameters
opt = tf.train.GradientDescentOptimizer(self.learning_rate)
gradients = tf.gradients(self.decoder_loss, self.params)
clipped_gradients, self.gradient_norm = tf.clip_by_global_norm(gradients,
max_gradient_norm)
self.update = opt.apply_gradients(zip(clipped_gradients, self.params),
global_step=self.global_step)
else:
# rnn decoder
self.decoder_distribution, _, _ = dynamic_rnn_decoder(cell, decoder_fn_inference,
scope="decoder")
print("self.decoder_distribution.shape():",self.decoder_distribution.get_shape())
self.decoder_distribution = tf.Print(self.decoder_distribution, ["distribution.shape()", tf.reduce_sum(self.decoder_distribution)])
# generating the response
self.generation_index = tf.argmax(tf.split(self.decoder_distribution,
[2, num_symbols-2], 2)[1], 2) + 2 # for removing UNK
self.generation = tf.nn.embedding_lookup(self.symbols, self.generation_index)
self.params = tf.trainable_variables()
self.saver = tf.train.Saver(tf.global_variables(), write_version=tf.train.SaverDef.V2,
max_to_keep=3, pad_step_number=True, keep_checkpoint_every_n_hours=1.0)
def __init__(self,
num_symbols,
num_embed_units,
num_units,
is_train,
vocab=None,
content_pos=None,
rhetoric_pos = None,
embed=None,
learning_rate=0.1,
learning_rate_decay_factor=0.9995,
max_gradient_norm=5.0,
max_length=30,
latent_size=128,
use_lstm=False,
num_classes=3,
full_kl_step=80000,
mem_slot_num=4,
mem_size=128):
self.ori_sents = tf.placeholder(tf.string, shape=(None, None))
self.ori_sents_length = tf.placeholder(tf.int32, shape=(None))
self.rep_sents = tf.placeholder(tf.string, shape=(None, None))
self.rep_sents_length = tf.placeholder(tf.int32, shape=(None))
self.labels = tf.placeholder(tf.float32, shape=(None, num_classes))
self.use_prior = tf.placeholder(tf.bool)
self.global_t = tf.placeholder(tf.int32)
self.content_mask = tf.reduce_sum(tf.one_hot(content_pos, num_symbols, 1.0, 0.0), axis = 0)
self.rhetoric_mask = tf.reduce_sum(tf.one_hot(rhetoric_pos, num_symbols, 1.0, 0.0), axis = 0)
topic_memory = tf.zeros(name="topic_memory", dtype=tf.float32,
shape=[None, mem_slot_num, mem_size])
w_topic_memory = tf.get_variable(name="w_topic_memory", dtype=tf.float32,
initializer=tf.random_uniform([mem_size, mem_size], -0.1, 0.1))
# build the vocab table (string to index)
if is_train:
self.symbols = tf.Variable(vocab, trainable=False, name="symbols")
else:
self.symbols = tf.Variable(np.array(['.']*num_symbols), name="symbols")
self.symbol2index = HashTable(KeyValueTensorInitializer(self.symbols,
tf.Variable(np.array([i for i in range(num_symbols)], dtype=np.int32), False)),
default_value=UNK_ID, name="symbol2index")
self.ori_sents_input = self.symbol2index.lookup(self.ori_sents)
self.rep_sents_target = self.symbol2index.lookup(self.rep_sents)
batch_size, decoder_len = tf.shape(self.rep_sents)[0], tf.shape(self.rep_sents)[1]
self.rep_sents_input = tf.concat([tf.ones([batch_size, 1], dtype=tf.int32)*GO_ID,
tf.split(self.rep_sents_target, [decoder_len-1, 1], 1)[0]], 1)
self.decoder_mask = tf.reshape(tf.cumsum(tf.one_hot(self.rep_sents_length-1,
decoder_len), reverse=True, axis=1), [-1, decoder_len])
# build the embedding table (index to vector)
if embed is None:
# initialize the embedding randomly
self.embed = tf.get_variable('embed', [num_symbols, num_embed_units], tf.float32)
else:
# initialize the embedding by pre-trained word vectors
self.embed = tf.get_variable('embed', dtype=tf.float32, initializer=embed)
self.pattern_embed = tf.get_variable('pattern_embed', [num_classes, num_embed_units], tf.float32)
self.encoder_input = tf.nn.embedding_lookup(self.embed, self.ori_sents_input)
self.decoder_input = tf.nn.embedding_lookup(self.embed, self.rep_sents_input)
if use_lstm:
cell_fw = LSTMCell(num_units)
cell_bw = LSTMCell(num_units)
cell_dec = LSTMCell(2*num_units)
else:
cell_fw = GRUCell(num_units)
cell_bw = GRUCell(num_units)
cell_dec = GRUCell(2*num_units)
# origin sentence encoder
with variable_scope.variable_scope("encoder"):
encoder_output, encoder_state = tf.nn.bidirectional_dynamic_rnn(cell_fw, cell_bw, self.encoder_input,
self.ori_sents_length, dtype=tf.float32)
post_sum_state = tf.concat(encoder_state, 1)
encoder_output = tf.concat(encoder_output, 2)
# response sentence encoder
with variable_scope.variable_scope("encoder", reuse = True):
decoder_state, decoder_last_state = tf.nn.bidirectional_dynamic_rnn(cell_fw, cell_bw, self.decoder_input,
self.rep_sents_length, dtype=tf.float32)
response_sum_state = tf.concat(decoder_last_state, 1)
# recognition network
with variable_scope.variable_scope("recog_net"):
recog_input = tf.concat([post_sum_state, response_sum_state], 1)
recog_mulogvar = tf.contrib.layers.fully_connected(recog_input, latent_size * 2, activation_fn=None, scope="muvar")
recog_mu, recog_logvar = tf.split(recog_mulogvar, 2, axis=1)
# prior network
with variable_scope.variable_scope("prior_net"):
prior_fc1 = tf.contrib.layers.fully_connected(post_sum_state, latent_size * 2, activation_fn=tf.tanh, scope="fc1")
prior_mulogvar = tf.contrib.layers.fully_connected(prior_fc1, latent_size * 2, activation_fn=None, scope="muvar")
prior_mu, prior_logvar = tf.split(prior_mulogvar, 2, axis=1)
latent_sample = tf.cond(self.use_prior,
lambda: sample_gaussian(prior_mu, prior_logvar),
lambda: sample_gaussian(recog_mu, recog_logvar))
# classifier
with variable_scope.variable_scope("classifier"):
classifier_input = latent_sample
pattern_fc1 = tf.contrib.layers.fully_connected(classifier_input, latent_size, activation_fn=tf.tanh, scope="pattern_fc1")
self.pattern_logits = tf.contrib.layers.fully_connected(pattern_fc1, num_classes, activation_fn=None, scope="pattern_logits")
self.label_embedding = tf.matmul(self.labels, self.pattern_embed)
output_fn, my_sequence_loss = output_projection_layer(2*num_units, num_symbols, latent_size, num_embed_units, self.content_mask, self.rhetoric_mask)
attention_keys, attention_values, attention_score_fn, attention_construct_fn = my_attention_decoder_fn.prepare_attention(encoder_output, 'luong', 2*num_units)
with variable_scope.variable_scope("dec_start"):
temp_start = tf.concat([post_sum_state, self.label_embedding, latent_sample], 1)
dec_fc1 = tf.contrib.layers.fully_connected(temp_start, 2*num_units, activation_fn=tf.tanh, scope="dec_start_fc1")
dec_fc2 = tf.contrib.layers.fully_connected(dec_fc1, 2*num_units, activation_fn=None, scope="dec_start_fc2")
if is_train:
# rnn decoder
topic_memory = self.update_memory(topic_memory, encoder_output)
extra_info = tf.concat([self.label_embedding, latent_sample, topic_memory], 1)
decoder_fn_train = my_attention_decoder_fn.attention_decoder_fn_train(dec_fc2,
attention_keys, attention_values, attention_score_fn, attention_construct_fn, extra_info)
self.decoder_output, _, _ = my_seq2seq.dynamic_rnn_decoder(cell_dec, decoder_fn_train,
self.decoder_input, self.rep_sents_length, scope = "decoder")
# calculate the loss
self.decoder_loss = my_loss.sequence_loss(logits = self.decoder_output,
targets = self.rep_sents_target, weights = self.decoder_mask,
extra_information = latent_sample, label_embedding = self.label_embedding, softmax_loss_function = my_sequence_loss)
temp_klloss = tf.reduce_mean(gaussian_kld(recog_mu, recog_logvar, prior_mu, prior_logvar))
self.kl_weight = tf.minimum(tf.to_float(self.global_t)/full_kl_step, 1.0)
self.klloss = self.kl_weight * temp_klloss
temp_labels = tf.argmax(self.labels, 1)
self.classifierloss = tf.reduce_mean(tf.nn.sparse_softmax_cross_entropy_with_logits(logits=self.pattern_logits, labels=temp_labels))
self.loss = self.decoder_loss + self.klloss + self.classifierloss # need to anneal the kl_weight
# building graph finished and get all parameters
self.params = tf.trainable_variables()
# initialize the training process
self.learning_rate = tf.Variable(float(learning_rate), trainable=False, dtype=tf.float32)
self.learning_rate_decay_op = self.learning_rate.assign(self.learning_rate * learning_rate_decay_factor)
self.global_step = tf.Variable(0, trainable=False)
# calculate the gradient of parameters
opt = tf.train.MomentumOptimizer(self.learning_rate, 0.9)
gradients = tf.gradients(self.loss, self.params)
clipped_gradients, self.gradient_norm = tf.clip_by_global_norm(gradients,
max_gradient_norm)
self.update = opt.apply_gradients(zip(clipped_gradients, self.params),
global_step=self.global_step)
else:
# rnn decoder
topic_memory = self.update_memory(topic_memory, encoder_output)
extra_info = tf.concat([self.label_embedding, latent_sample, topic_memory], 1)
decoder_fn_inference = my_attention_decoder_fn.attention_decoder_fn_inference(output_fn,
dec_fc2, attention_keys, attention_values, attention_score_fn,
attention_construct_fn, self.embed, GO_ID, EOS_ID, max_length, num_symbols, extra_info)
self.decoder_distribution, _, _ = my_seq2seq.dynamic_rnn_decoder(cell_dec, decoder_fn_inference, scope="decoder")
self.generation_index = tf.argmax(tf.split(self.decoder_distribution,
[2, num_symbols-2], 2)[1], 2) + 2 # for removing UNK
self.generation = tf.nn.embedding_lookup(self.symbols, self.generation_index)
self.params = tf.trainable_variables()
self.saver = tf.train.Saver(tf.global_variables(), write_version=tf.train.SaverDef.V2,
max_to_keep=3, pad_step_number=True, keep_checkpoint_every_n_hours=1.0)
def __init__(self,
num_symbols,
num_embed_units,
num_units,
vocab=None,
embed=None,
name_scope=None,
learning_rate=0.0001,
learning_rate_decay_factor=0.95,
max_gradient_norm=5,
l2_lambda=0.2):
self.posts = tf.placeholder(tf.string, shape=[None,
None]) # batch * len
self.posts_length = tf.placeholder(tf.int32, shape=[None]) # batch
self.responses = tf.placeholder(tf.string, shape=[None,
None]) # batch*len
self.responses_length = tf.placeholder(tf.int32, shape=[None]) # batch
self.generation = tf.placeholder(tf.string, shape=[None,
None]) # batch*len
self.generation_length = tf.placeholder(tf.int32,
shape=[None]) # batch
# build the vocab table (string to index)
self.symbols = tf.Variable(vocab, trainable=False, name="symbols")
self.symbol2index = HashTable(KeyValueTensorInitializer(
self.symbols,
tf.Variable(
np.array([i for i in range(num_symbols)], dtype=np.int32),
False)),
default_value=UNK_ID,
name="symbol2index")
# build the embedding table (index to vector)
if embed is None:
# initialize the embedding randomly
self.embed = tf.get_variable('embed',
[num_symbols, num_embed_units],
tf.float32)
else:
# initialize the embedding by pre-trained word vectors
self.embed = tf.get_variable('embed',
dtype=tf.float32,
initializer=embed)
self.posts_input = self.symbol2index.lookup(
self.posts) # batch * utter_len
self.posts_input_embed = tf.nn.embedding_lookup(
self.embed, self.posts_input) #batch * utter_len * embed_unit
self.responses_input = self.symbol2index.lookup(self.responses)
self.responses_input_embed = tf.nn.embedding_lookup(
self.embed, self.responses_input) # batch * utter_len * embed_unit
self.generation_input = self.symbol2index.lookup(self.generation)
self.generation_input_embed = tf.nn.embedding_lookup(
self.embed,
self.generation_input) # batch * utter_len * embed_unit
# Construct bidirectional GRU cells for encoder / decoder
cell_fw_post = GRUCell(num_units)
cell_bw_post = GRUCell(num_units)
cell_fw_resp = GRUCell(num_units)
cell_bw_resp = GRUCell(num_units)
# Encode the post sequence
with variable_scope.variable_scope("post_encoder"):
posts_state, posts_final_state = tf.nn.bidirectional_dynamic_rnn(
cell_fw_post,
cell_bw_post,
self.posts_input_embed,
self.posts_length,
dtype=tf.float32)
posts_final_state_bid = tf.concat(
posts_final_state, 1) # batch_size * (2 * num_units)
# Encode the real response sequence
with variable_scope.variable_scope("resp_encoder"):
responses_state, responses_final_state = tf.nn.bidirectional_dynamic_rnn(
cell_fw_resp,
cell_bw_resp,
self.responses_input_embed,
self.responses_length,
dtype=tf.float32)
responses_final_state_bid = tf.concat(responses_final_state, 1)
# Encode the generated response sequence
with variable_scope.variable_scope("resp_encoder", reuse=True):
generation_state, generation_final_state = tf.nn.bidirectional_dynamic_rnn(
cell_fw_resp,
cell_bw_resp,
self.generation_input_embed,
self.generation_length,
dtype=tf.float32)
generation_final_state_bid = tf.concat(generation_final_state, 1)
# Calculate the relevance score between post and real response
with variable_scope.variable_scope("calibration"):
self.W = tf.get_variable('W', [2 * num_units, 2 * num_units],
tf.float32)
vec_post = tf.reshape(posts_final_state_bid,
[-1, 1, 2 * num_units])
vec_resp = tf.reshape(responses_final_state_bid,
[-1, 2 * num_units, 1])
attn_score_true = tf.einsum(
'aij,ajk->aik', tf.einsum('aij,jk->aik', vec_post, self.W),
vec_resp)
attn_score_true = tf.reshape(attn_score_true, [-1, 1])
fc_true_input = tf.concat([
posts_final_state_bid, responses_final_state_bid,
attn_score_true
], 1)
self.output_fc_W = tf.get_variable("output_fc_W",
[4 * num_units + 1, num_units],
tf.float32)
self.output_fc_b = tf.get_variable("output_fc_b", [num_units],
tf.float32)
fc_true = tf.nn.tanh(
tf.nn.xw_plus_b(fc_true_input, self.output_fc_W,
self.output_fc_b)) # batch_size
self.output_W = tf.get_variable("output_W", [num_units, 1],
tf.float32)
self.output_b = tf.get_variable("output_b", [1], tf.float32)
self.cost_true = tf.nn.sigmoid(
tf.nn.xw_plus_b(fc_true, self.output_W,
self.output_b)) # batch_size
# Calculate the relevance score between post and generated response
with variable_scope.variable_scope("calibration", reuse=True):
vec_gen = tf.reshape(generation_final_state_bid,
[-1, 2 * num_units, 1])
attn_score_false = tf.einsum(
'aij,ajk->aik', tf.einsum('aij,jk->aik', vec_post, self.W),
vec_gen)
attn_score_false = tf.reshape(attn_score_false, [-1, 1])
fc_false_input = tf.concat([
posts_final_state_bid, generation_final_state_bid,
attn_score_false
], 1)
fc_false = tf.nn.tanh(
tf.nn.xw_plus_b(fc_false_input, self.output_fc_W,
self.output_fc_b)) # batch_size
self.cost_false = tf.nn.sigmoid(
tf.nn.xw_plus_b(fc_false, self.output_W,
self.output_b)) # batch_size
self.PR_cost = tf.reduce_mean(
tf.reduce_sum(tf.square(self.cost_true - 1.0), axis=1))
self.PG_cost = tf.reduce_mean(
tf.reduce_sum(tf.square(self.cost_false), axis=1))
# Use the loss similar to least square GAN
self.cost = self.PR_cost / 2.0 + self.PG_cost / 2.0 + l2_lambda * (
tf.nn.l2_loss(self.output_fc_W) + tf.nn.l2_loss(self.output_fc_b) +
tf.nn.l2_loss(self.output_W) + tf.nn.l2_loss(self.output_b) +
tf.nn.l2_loss(self.W))
# building graph finished and get all parameters
self.params = [
k for k in tf.trainable_variables() if name_scope in k.name
]
# initialize the training process
self.learning_rate = tf.Variable(float(learning_rate),
trainable=False,
dtype=tf.float32)
self.learning_rate_decay_op = self.learning_rate.assign(
self.learning_rate * learning_rate_decay_factor)
self.global_step = tf.Variable(0, trainable=False)
self.adv_global_step = tf.Variable(0, trainable=False)
# calculate the gradient of parameters
opt = tf.train.AdamOptimizer(self.learning_rate)
gradients = tf.gradients(self.cost, self.params)
clipped_gradients, self.gradient_norm = tf.clip_by_global_norm(
gradients, max_gradient_norm)
self.update = opt.apply_gradients(zip(clipped_gradients, self.params),
global_step=self.global_step)
self.reward = tf.reduce_sum(self.cost_false, axis=1) # batch
all_variables = [
k for k in tf.global_variables() if name_scope in k.name
]
self.saver = tf.train.Saver(all_variables,
write_version=tf.train.SaverDef.V2,
max_to_keep=5,
pad_step_number=True,
keep_checkpoint_every_n_hours=1.0)
self.adv_saver = tf.train.Saver(all_variables,
write_version=tf.train.SaverDef.V2,
max_to_keep=5,
pad_step_number=True,
keep_checkpoint_every_n_hours=1.0)