def __init__(self, data, args, embed):
self.init_states = tf.placeholder(tf.float32, (None, args.ch_size),
'ctx_inps') # batch*ch_size
self.posts = tf.placeholder(tf.int32, (None, None),
'enc_inps') # batch*len
self.posts_length = tf.placeholder(tf.int32, (None, ),
'enc_lens') # batch
self.prev_posts = tf.placeholder(tf.int32, (None, None),
'enc_prev_inps')
self.prev_posts_length = tf.placeholder(tf.int32, (None, ),
'enc_prev_lens')
self.kgs = tf.placeholder(tf.int32, (None, None, None),
'kg_inps') # batch*len
self.kgs_h_length = tf.placeholder(tf.int32, (None, None),
'kg_h_lens') # batch
self.kgs_hr_length = tf.placeholder(tf.int32, (None, None),
'kg_hr_lens') # batch
self.kgs_hrt_length = tf.placeholder(tf.int32, (None, None),
'kg_hrt_lens') # batch
self.kgs_index = tf.placeholder(tf.float32, (None, None),
'kg_indices') # batch
self.origin_responses = tf.placeholder(tf.int32, (None, None),
'dec_inps') # batch*len
self.origin_responses_length = tf.placeholder(tf.int32, (None, ),
'dec_lens') # batch
self.context_length = tf.placeholder(tf.int32, (None, ), 'ctx_lens')
self.is_train = tf.placeholder(tf.bool)
num_past_turns = tf.shape(self.posts)[0] // tf.shape(
self.origin_responses)[0]
# deal with original data to adapt encoder and decoder
batch_size, decoder_len = tf.shape(self.origin_responses)[0], tf.shape(
self.origin_responses)[1]
self.responses = tf.split(self.origin_responses, [1, decoder_len - 1],
1)[1] # no go_id
self.responses_length = self.origin_responses_length - 1
self.responses_input = tf.split(self.origin_responses,
[decoder_len - 1, 1],
1)[0] # no eos_id
self.responses_target = self.responses
decoder_len = decoder_len - 1
self.posts_input = self.posts # 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])
kg_len = tf.shape(self.kgs)[2]
kg_h_mask = tf.reshape(
tf.cumsum(tf.one_hot(self.kgs_h_length - 1, kg_len),
reverse=True,
axis=2), [batch_size, -1, kg_len, 1])
kg_hr_mask = tf.reshape(
tf.cumsum(tf.one_hot(self.kgs_hr_length - 1, kg_len),
reverse=True,
axis=2), [batch_size, -1, kg_len, 1])
kg_hrt_mask = tf.reshape(
tf.cumsum(tf.one_hot(self.kgs_hrt_length - 1, kg_len),
reverse=True,
axis=2), [batch_size, -1, kg_len, 1])
kg_key_mask = kg_hr_mask
kg_value_mask = kg_hrt_mask - kg_hr_mask
# 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 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.encoder_input = tf.nn.embedding_lookup(self.embed, self.posts)
self.decoder_input = tf.nn.embedding_lookup(self.embed,
self.responses_input)
self.kg_input = tf.nn.embedding_lookup(self.embed, self.kgs)
#self.knowledge_max = tf.reduce_max(tf.where(tf.cast(tf.tile(knowledge_mask, [1, 1, args.embedding_size]), tf.bool), self.knowledge_input, -mask_value), axis=1)
#self.knowledge_min = tf.reduce_max(tf.where(tf.cast(tf.tile(knowledge_mask, [1, 1, args.embedding_size]), tf.bool), self.knowledge_input, mask_value), axis=1)
self.kg_key_avg = tf.reduce_sum(
self.kg_input * kg_key_mask, axis=2) / tf.maximum(
tf.reduce_sum(kg_key_mask, axis=2),
tf.ones_like(tf.expand_dims(self.kgs_hrt_length, -1),
dtype=tf.float32))
self.kg_value_avg = tf.reduce_sum(
self.kg_input * kg_value_mask, axis=2) / tf.maximum(
tf.reduce_sum(kg_value_mask, axis=2),
tf.ones_like(tf.expand_dims(self.kgs_hrt_length, -1),
dtype=tf.float32))
#self.encoder_input = tf.cond(self.is_train,
# lambda: tf.nn.dropout(tf.nn.embedding_lookup(self.embed, self.posts_input), 0.8),
# lambda: tf.nn.embedding_lookup(self.embed, self.posts_input)) # batch*len*unit
#self.decoder_input = tf.cond(self.is_train,
# lambda: tf.nn.dropout(tf.nn.embedding_lookup(self.embed, self.responses_input), 0.8),
# lambda: tf.nn.embedding_lookup(self.embed, self.responses_input))
# build rnn_cell
cell_enc = tf.nn.rnn_cell.GRUCell(args.eh_size)
cell_ctx = tf.nn.rnn_cell.GRUCell(args.ch_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.posts_length,
dtype=tf.float32,
scope="encoder_rnn")
with tf.variable_scope('encoder', reuse=tf.AUTO_REUSE):
prev_output, _ = dynamic_rnn(cell_enc,
tf.nn.embedding_lookup(
self.embed, self.prev_posts),
self.prev_posts_length,
dtype=tf.float32,
scope="encoder_rnn")
with tf.variable_scope('context'):
encoder_state_reshape = tf.reshape(
encoder_state, [-1, num_past_turns, args.eh_size])
_, self.context_state = dynamic_rnn(cell_ctx,
encoder_state_reshape,
self.context_length,
dtype=tf.float32,
scope='context_rnn')
# get output projection function
output_fn = MyDense(data.vocab_size, use_bias=True)
sampled_sequence_loss = output_projection_layer(
args.dh_size, data.vocab_size, args.softmax_samples)
# construct attention
'''
encoder_len = tf.shape(encoder_output)[1]
attention_memory = tf.reshape(encoder_output, [batch_size, -1, args.eh_size])
attention_mask = tf.reshape(tf.sequence_mask(self.posts_length, encoder_len), [batch_size, -1])
attention_mask = tf.concat([tf.ones([batch_size, 1], tf.bool), attention_mask[:,1:]], axis=1)
attn_mechanism = MyAttention(args.dh_size, attention_memory, attention_mask)
'''
attn_mechanism = tf.contrib.seq2seq.BahdanauAttention(
args.dh_size,
prev_output,
memory_sequence_length=tf.maximum(self.prev_posts_length, 1))
cell_dec_attn = tf.contrib.seq2seq.AttentionWrapper(
cell_dec, attn_mechanism, attention_layer_size=args.dh_size)
ctx_state_shaping = tf.layers.dense(self.context_state,
args.dh_size,
activation=None)
dec_start = cell_dec_attn.zero_state(
batch_size, dtype=tf.float32).clone(cell_state=ctx_state_shaping)
# calculate kg embedding
with tf.variable_scope('knowledge'):
query = tf.reshape(
tf.layers.dense(tf.concat(self.context_state, axis=-1),
args.embedding_size,
use_bias=False),
[batch_size, 1, args.embedding_size])
kg_score = tf.reduce_sum(query * self.kg_key_avg, axis=2)
kg_score = tf.where(tf.greater(self.kgs_hrt_length, 0), kg_score,
-tf.ones_like(kg_score) * np.inf)
kg_alignment = tf.nn.softmax(kg_score)
kg_max = tf.argmax(kg_alignment, axis=-1)
kg_max_onehot = tf.one_hot(kg_max,
tf.shape(kg_alignment)[1],
dtype=tf.float32)
self.kg_acc = tf.reduce_sum(
kg_max_onehot * self.kgs_index) / tf.maximum(
tf.reduce_sum(tf.reduce_max(self.kgs_index, axis=-1)),
tf.constant(1.0))
self.kg_loss = tf.reduce_sum(
-tf.log(tf.clip_by_value(kg_alignment, 1e-12, 1.0)) *
self.kgs_index,
axis=1) / tf.maximum(tf.reduce_sum(self.kgs_index, axis=1),
tf.ones([batch_size], dtype=tf.float32))
self.kg_loss = tf.reduce_mean(self.kg_loss)
self.knowledge_embed = tf.reduce_sum(
tf.expand_dims(kg_alignment, axis=-1) * self.kg_value_avg *
tf.cast(kg_num_mask, tf.float32),
axis=1)
#self.knowledge_embed = tf.Print(self.knowledge_embed, ['acc', self.kg_acc, 'loss', self.kg_loss])
knowledge_embed_extend = tf.tile(
tf.expand_dims(self.knowledge_embed, axis=1), [1, decoder_len, 1])
self.decoder_input = tf.concat(
[self.decoder_input, knowledge_embed_extend], axis=2)
# construct helper
train_helper = tf.contrib.seq2seq.TrainingHelper(
self.decoder_input, tf.maximum(self.responses_length, 1))
infer_helper = MyInferenceHelper(self.embed,
tf.fill([batch_size], data.go_id),
data.eos_id, self.knowledge_embed)
#infer_helper = tf.contrib.seq2seq.GreedyEmbeddingHelper(self.embed, tf.fill([batch_size], data.go_id), data.eos_id)
# build decoder (train)
with tf.variable_scope('decoder'):
decoder_train = tf.contrib.seq2seq.BasicDecoder(
cell_dec_attn, train_helper, dec_start)
train_outputs, _, _ = tf.contrib.seq2seq.dynamic_decode(
decoder_train, impute_finished=True, scope="decoder_rnn")
self.decoder_output = train_outputs.rnn_output
#self.decoder_output = tf.nn.dropout(self.decoder_output, 0.8)
self.decoder_distribution_teacher, self.decoder_loss, self.decoder_all_loss = \
sampled_sequence_loss(self.decoder_output, self.responses_target, self.decoder_mask)
# build decoder (test)
with tf.variable_scope('decoder', reuse=True):
decoder_infer = tf.contrib.seq2seq.BasicDecoder(
cell_dec_attn, infer_helper, dec_start, output_layer=output_fn)
infer_outputs, _, _ = tf.contrib.seq2seq.dynamic_decode(
decoder_infer,
impute_finished=True,
maximum_iterations=args.max_sent_length,
scope="decoder_rnn")
self.decoder_distribution = infer_outputs.rnn_output
self.generation_index = tf.argmax(
tf.split(self.decoder_distribution, [2, data.vocab_size - 2],
2)[1], 2) + 2 # for removing UNK
# 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.AdamOptimizer(self.learning_rate)
self.loss = self.decoder_loss + self.kg_loss
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, data, args, embed):
self.posts = tf.placeholder(tf.int32, (None, None),
'enc_inps') # batch*len
self.posts_length = tf.placeholder(tf.int32, (None, ),
'enc_lens') # batch
self.origin_responses = tf.placeholder(tf.int32, (None, None),
'dec_inps') # batch*len
self.origin_responses_length = tf.placeholder(tf.int32, (None, ),
'dec_lens') # batch
self.is_train = tf.placeholder(tf.bool)
# deal with original data to adapt encoder and decoder
batch_size, decoder_len = tf.shape(self.origin_responses)[0], tf.shape(
self.origin_responses)[1]
self.responses_input = tf.split(self.origin_responses,
[decoder_len - 1, 1], 1)[0]
self.responses_target = tf.split(self.origin_responses,
[1, decoder_len - 1], 1)[1]
self.responses_length = self.origin_responses_length - 1
decoder_len = decoder_len - 1
self.decoder_mask = tf.reshape(
tf.cumsum(tf.one_hot(self.responses_length - 1, decoder_len),
reverse=True,
axis=1), [-1, decoder_len])
# 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 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.encoder_input = tf.nn.embedding_lookup(self.embed, self.posts)
self.decoder_input = tf.nn.embedding_lookup(self.embed,
self.responses_input)
#self.decoder_input = tf.cond(self.is_train,
# lambda: tf.nn.dropout(tf.nn.embedding_lookup(self.embed, self.responses_input), 0.8),
# lambda: tf.nn.embedding_lookup(self.embed, self.responses_input))
# build rnn_cell
cell = tf.nn.rnn_cell.GRUCell(args.eh_size)
# get output projection function
output_fn = MyDense(data.vocab_size, use_bias=True)
sampled_sequence_loss = output_projection_layer(
args.dh_size, data.vocab_size, args.softmax_samples)
# build encoder
with tf.variable_scope('decoder', reuse=tf.AUTO_REUSE):
_, self.encoder_state = dynamic_rnn(cell,
self.encoder_input,
self.posts_length,
dtype=tf.float32,
scope="decoder_rnn")
# construct helper and attention
infer_helper = tf.contrib.seq2seq.GreedyEmbeddingHelper(
self.embed, tf.fill([batch_size], data.eos_id), data.eos_id)
dec_start = tf.cond(
self.is_train,
lambda: tf.zeros([batch_size, args.dh_size], dtype=tf.float32),
lambda: self.encoder_state)
# build decoder (train)
with tf.variable_scope('decoder', reuse=tf.AUTO_REUSE):
self.decoder_output, _ = dynamic_rnn(
cell,
self.decoder_input,
self.responses_length,
dtype=tf.float32,
initial_state=self.encoder_state,
scope='decoder_rnn')
#self.decoder_output = tf.nn.dropout(self.decoder_output, 0.8)
self.decoder_distribution_teacher, self.decoder_loss, self.decoder_all_loss = \
sampled_sequence_loss(self.decoder_output, self.responses_target, self.decoder_mask)
# build decoder (test)
with tf.variable_scope('decoder', reuse=tf.AUTO_REUSE):
decoder_infer = tf.contrib.seq2seq.BasicDecoder(
cell, infer_helper, dec_start, output_layer=output_fn)
infer_outputs, _, _ = tf.contrib.seq2seq.dynamic_decode(
decoder_infer,
impute_finished=True,
maximum_iterations=args.max_sent_length,
scope="decoder_rnn")
self.decoder_distribution = infer_outputs.rnn_output
self.generation_index = tf.argmax(
tf.split(self.decoder_distribution, [2, data.vocab_size - 2],
2)[1], 2) + 2 # for removing UNK
# 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.AdamOptimizer(self.learning_rate)
gradients = tf.gradients(self.decoder_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, data, args, embed):
# 定义输入的占位符
self.posts = tf.placeholder(tf.int32, (None, None),
'enc_inps') # batch*len
self.posts_length = tf.placeholder(tf.int32, (None, ),
'enc_lens') # batch
self.origin_responses = tf.placeholder(tf.int32, (None, None),
'dec_inps') # batch*len
self.origin_responses_length = tf.placeholder(tf.int32, (None, ),
'dec_lens') # batch
self.is_train = tf.placeholder(tf.bool)
# deal with original data to adapt encoder and decoder
# 记录batch_size以及response的长度
batch_size, decoder_len = tf.shape(self.origin_responses)[0], tf.shape(
self.origin_responses)[1]
# 定义输入和输出，对应的长度都是decoder_len-1
# input是去除最后一个位置的token，target是去除第一个位置的token
self.responses_input = tf.split(self.origin_responses,
[decoder_len - 1, 1], 1)[0]
self.responses_target = tf.split(self.origin_responses,
[1, decoder_len - 1], 1)[1]
self.responses_length = self.origin_responses_length - 1
decoder_len = decoder_len - 1
# 定义decoder的mask矩阵，[batch_size, decoder_len]
self.decoder_mask = tf.reshape(
tf.cumsum(tf.one_hot(self.responses_length - 1, decoder_len),
reverse=True,
axis=1), [-1, decoder_len])
# initialize the training process
# 初始化训练参数，学习率等
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 the embedding table and embedding input
# 定义词向量矩阵
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.encoder_input = tf.nn.embedding_lookup(self.embed, self.posts)
self.decoder_input = tf.nn.embedding_lookup(self.embed,
self.responses_input)
#self.decoder_input = tf.cond(self.is_train,
# lambda: tf.nn.dropout(tf.nn.embedding_lookup(self.embed, self.responses_input), 0.8),
# lambda: tf.nn.embedding_lookup(self.embed, self.responses_input))
# build rnn_cell
# 定义GRU单元，这里的eh_size表示隐层的单元数
cell = tf.nn.rnn_cell.GRUCell(args.eh_size)
# get output projection function
# 映射到词表分布上
output_fn = MyDense(data.vocab_size, use_bias=True)
# dh_size表示解码器的隐层输出
# vocab_size表示词表的大小
sampled_sequence_loss = output_projection_layer(
args.dh_size, data.vocab_size, args.softmax_samples)
# build encoder
# 这里主要用于测试阶段，通过对post编码得到隐向量
# 如果是训练阶段，这里应该是全0的矩阵
with tf.variable_scope('decoder', reuse=tf.AUTO_REUSE):
_, self.encoder_state = tf.nn.dynamic_rnn(cell,
self.encoder_input,
self.posts_length,
dtype=tf.float32,
scope="decoder_rnn")
# construct helper and attention
# 这里之所以填充eos_id，是因为在解码时，decoder的输入第一个字符就是<eos>
# 这在对输入数据进行封装的时候就定义好了
infer_helper = tf.contrib.seq2seq.GreedyEmbeddingHelper(
self.embed, tf.fill([batch_size], data.eos_id), data.eos_id)
dec_start = tf.cond(
self.is_train,
lambda: tf.zeros([batch_size, args.dh_size], dtype=tf.float32),
lambda: self.encoder_state)
# build decoder (train)
with tf.variable_scope('decoder', reuse=tf.AUTO_REUSE):
# 这里的Output是[batch_size, decoder_length, hidden_size]
self.decoder_output, _ = tf.nn.dynamic_rnn(cell,
self.decoder_input,
self.responses_length,
dtype=tf.float32,
initial_state=dec_start,
scope='decoder_rnn')
#self.decoder_output = tf.nn.dropout(self.decoder_output, 0.8)
# decoder_output的维度是[batch_size, decoder_length, hidden_size]
# responses_target的维度是[batch_size, decoder_length]
# decoder_mask的维度是[batch_size, decoder_mask]
# 输出decoder_distribution_teacher的维度是[batch_size, decoder_len, vocab_size]
# 输出的decoder_loss是0维的平均损失
# 输出的decoder_all_loss是每一个样例一句话的损失[batch_size,]
self.decoder_distribution_teacher, self.decoder_loss, self.decoder_all_loss = \
sampled_sequence_loss(self.decoder_output, self.responses_target, self.decoder_mask)
# build decoder (test)
with tf.variable_scope('decoder', reuse=tf.AUTO_REUSE):
decoder_infer = tf.contrib.seq2seq.BasicDecoder(
cell, infer_helper, dec_start, output_layer=output_fn)
infer_outputs, _, _ = tf.contrib.seq2seq.dynamic_decode(
decoder_infer,
impute_finished=True,
maximum_iterations=args.max_decoder_length,
scope="decoder_rnn")
# [batch_size, max_decoder_length, vocab_size]
self.decoder_distribution = infer_outputs.rnn_output
# 得到生成的单词的索引[batch_size, max_decoder_length]
# 这里由于前4个单词是["<pad>", "<unk>", "<go>", "<eos>"]
# 所以要去除<pad>和<unk>这两个单词
self.generation_index = tf.argmax(
tf.split(self.decoder_distribution, [2, data.vocab_size - 2],
2)[1], 2) + 2 # for removing UNK
# 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.AdamOptimizer(self.learning_rate)
gradients = tf.gradients(self.decoder_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
# 记录参数
self.create_summary(args)
def __init__(self, data, args, embed):
# posts表示编码器，即历史对话输入 [batch, encoder_len]
# posts_length表示输入的每一句话的实际长度 [batch]
# prev_length除去最后一轮，之前轮次语句的长度（包含<go>和<eos>），[batch]
self.posts = tf.placeholder(tf.int32, (None, None),
'enc_inps') # batch*len
self.posts_length = tf.placeholder(tf.int32, (None, ),
'enc_lens') # batch
self.prevs_length = tf.placeholder(tf.int32, (None, ),
'enc_lens_prev') # batch
# origin_responses表示回复的内容，[batch, resp_len]
# origin_responses_length表示每一个回复的实际长度，[batch, ]
self.origin_responses = tf.placeholder(tf.int32, (None, None),
'dec_inps') # batch*len
self.origin_responses_length = tf.placeholder(tf.int32, (None, ),
'dec_lens') # batch
self.is_train = tf.placeholder(tf.bool)
# deal with original data to adapt encoder and decoder
batch_size, decoder_len = tf.shape(self.origin_responses)[0], tf.shape(
self.origin_responses)[1]
# 这里对回复进行分割，此时祛除了回复中的go_id
self.responses = tf.split(self.origin_responses, [1, decoder_len - 1],
1)[1] # no go_id
self.responses_length = self.origin_responses_length - 1
# 这里得到解码器的输入和输出，输入去除了最后的eos_id，输出去除了最开始的go_id，这样保证对齐
# [batch, decoder_len]（这里的decoder_len等于resp_len-1）
self.responses_input = tf.split(self.origin_responses,
[decoder_len - 1, 1],
1)[0] # no eos_id
self.responses_target = self.responses
decoder_len = decoder_len - 1
# 编码器输入 [batch, encoder_len]
self.posts_input = self.posts # batch*len
# 这里计算decoder的mask矩阵
# 等于[batch, decoder_len]
self.decoder_mask = tf.reshape(
tf.cumsum(tf.one_hot(self.responses_length - 1, decoder_len),
reverse=True,
axis=1), [-1, decoder_len])
# 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 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)
# 将编码器和解码器的输入转化为词向量
# encoder_input: [batch, encoder_len, embed_size]
# decoder_input: [batch, decoder_len, embed_size]
self.encoder_input = tf.nn.embedding_lookup(self.embed, self.posts)
self.decoder_input = tf.nn.embedding_lookup(self.embed,
self.responses_input)
#self.encoder_input = tf.cond(self.is_train,
# lambda: tf.nn.dropout(tf.nn.embedding_lookup(self.embed, self.posts_input), 0.8),
# lambda: tf.nn.embedding_lookup(self.embed, self.posts_input)) #batch*len*unit
#self.decoder_input = tf.cond(self.is_train,
# lambda: tf.nn.dropout(tf.nn.embedding_lookup(self.embed, self.responses_input), 0.8),
# lambda: tf.nn.embedding_lookup(self.embed, self.responses_input))
# 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: [batch, encoder_len, eh_size]
# encoder_state: [batch, eh_size]
encoder_output, encoder_state = tf.nn.dynamic_rnn(
cell_enc,
self.encoder_input,
self.posts_length,
dtype=tf.float32,
scope="encoder_rnn")
# get output projection function
output_fn = MyDense(data.vocab_size, use_bias=True)
sampled_sequence_loss = output_projection_layer(
args.dh_size, data.vocab_size, args.softmax_samples)
encoder_len = tf.shape(encoder_output)[1]
# 这里计算posts和prevs的mask矩阵
posts_mask = tf.sequence_mask(self.posts_length, encoder_len)
prevs_mask = tf.sequence_mask(self.prevs_length, encoder_len)
# 不同为1，相同为1
# 这里表示只关注最后一轮，[batch, encoder_len]
attention_mask = tf.reshape(tf.logical_xor(posts_mask, prevs_mask),
[batch_size, encoder_len])
# construct helper and attention
train_helper = tf.contrib.seq2seq.TrainingHelper(
self.decoder_input, self.responses_length)
# 这里在推理的时候，起始位置全部使用go_id进行填充
# 这在对输入数据进行封装时即进行了定义
infer_helper = tf.contrib.seq2seq.GreedyEmbeddingHelper(
self.embed, tf.fill([batch_size], data.go_id), data.eos_id)
# 这里编码器是按照多轮输入进行编码的
# 但是解码器在attention的时候只关注最后一轮输入
# 这里定义输入输出attention
attn_mechanism = MyAttention(args.dh_size, encoder_output,
attention_mask)
cell_dec_attn = tf.contrib.seq2seq.AttentionWrapper(
cell_dec, attn_mechanism, attention_layer_size=args.dh_size)
# 把编码器最后一层的隐状态映射到解码器隐状态的维度
# [batch, dh_size]
enc_state_shaping = tf.layers.dense(encoder_state,
args.dh_size,
activation=None)
dec_start = cell_dec_attn.zero_state(
batch_size, dtype=tf.float32).clone(cell_state=enc_state_shaping)
# build decoder (train)
with tf.variable_scope('decoder'):
decoder_train = tf.contrib.seq2seq.BasicDecoder(
cell_dec_attn, train_helper, dec_start)
train_outputs, _, _ = tf.contrib.seq2seq.dynamic_decode(
decoder_train, impute_finished=True, scope="decoder_rnn")
self.decoder_output = train_outputs.rnn_output
#self.decoder_output = tf.nn.dropout(self.decoder_output, 0.8)
# 计算损失和概率分布
# decoder_distribution_teacher：[batch, decoder_length, vocab_size] （这里都是对数概率）
# decoder_loss，基于这个batch中所有词的损失，0维
# decoder_all_loss，每一句话的损失，[batch, ]
self.decoder_distribution_teacher, self.decoder_loss, self.decoder_all_loss = \
sampled_sequence_loss(self.decoder_output, self.responses_target, self.decoder_mask)
# build decoder (test)
with tf.variable_scope('decoder', reuse=True):
# 这里output_fn会重用上面的权重和偏置
decoder_infer = tf.contrib.seq2seq.BasicDecoder(
cell_dec_attn, infer_helper, dec_start, output_layer=output_fn)
infer_outputs, _, _ = tf.contrib.seq2seq.dynamic_decode(
decoder_infer,
impute_finished=True,
maximum_iterations=args.max_decoder_length,
scope="decoder_rnn")
# [batch, max_decoder_len, vocab_size]
self.decoder_distribution = infer_outputs.rnn_output
# 这里在计算索引概率最大值的去除前面两个<pad>和<unk>的影响
self.generation_index = tf.argmax(
tf.split(self.decoder_distribution, [2, data.vocab_size - 2],
2)[1], 2) + 2 # for removing UNK
# 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.AdamOptimizer(self.learning_rate) # 定义优化器
gradients = tf.gradients(self.decoder_loss, self.params) # 计算参数的梯度
clipped_gradients, self.gradient_norm = tf.clip_by_global_norm(
gradients, args.grad_clip) # 梯度裁剪
self.update = opt.apply_gradients(
zip(clipped_gradients,
self.params), global_step=self.global_step) # 对参数进行更新
# 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, data, args, embed):
#self.init_states = tf.placeholder(tf.float32, (None, args.ch_size), 'ctx_inps') # batch*ch_size
# posts: [batch*(num_turns-1), max_post_length]
# posts_length: [batch*(num_turns-1),]
self.posts = tf.placeholder(tf.int32, (None, None),
'enc_inps') # batch * num_turns-1 * len
self.posts_length = tf.placeholder(tf.int32, (None, ),
'enc_lens') # batch * num_turns-1
# prev_posts: [batch, max_prev_length]，即对应上面post的最后一轮
# prev_posts_length: [batch]，即最后一轮每句话的实际长度
self.prev_posts = tf.placeholder(tf.int32, (None, None),
'enc_prev_inps')
self.prev_posts_length = tf.placeholder(tf.int32, (None, ),
'enc_prev_lens')
# origin_responses: [batch, max_response_length]
# origin_responses_length: [batch]
self.origin_responses = tf.placeholder(tf.int32, (None, None),
'dec_inps') # batch*len
self.origin_responses_length = tf.placeholder(tf.int32, (None, ),
'dec_lens') # batch
# context_length: [batch]，表示每一个posts的实际轮次
self.context_length = tf.placeholder(tf.int32, (None, ), 'ctx_lens')
self.is_train = tf.placeholder(tf.bool)
# 即对应num_turns-1（也有可能比这个小）
# 表示当前batch的实际最大轮次
num_past_turns = tf.shape(self.posts)[0] // tf.shape(
self.origin_responses)[0]
# deal with original data to adapt encoder and decoder
# 获取解码器的输入和输出
# 其中输入没有最后的<eos>，输出没有最开始的<go>
batch_size, decoder_len = tf.shape(self.origin_responses)[0], tf.shape(
self.origin_responses)[1]
self.responses = tf.split(self.origin_responses, [1, decoder_len - 1],
1)[1] # no go_id
self.responses_length = self.origin_responses_length - 1
self.responses_input = tf.split(self.origin_responses,
[decoder_len - 1, 1],
1)[0] # no eos_id
self.responses_target = self.responses
decoder_len = decoder_len - 1
self.posts_input = self.posts # batch*len
# [batch, decoder_length]
self.decoder_mask = tf.reshape(
tf.cumsum(tf.one_hot(self.responses_length - 1, decoder_len),
reverse=True,
axis=1), [-1, decoder_len])
# 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 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.encoder_input = tf.nn.embedding_lookup(self.embed, self.posts)
self.decoder_input = tf.nn.embedding_lookup(self.embed,
self.responses_input)
# self.encoder_input = tf.cond(self.is_train,
# lambda: tf.nn.dropout(tf.nn.embedding_lookup(self.embed, self.posts_input), 0.8),
# lambda: tf.nn.embedding_lookup(self.embed, self.posts_input)) # batch*len*unit
# self.decoder_input = tf.cond(self.is_train,
# lambda: tf.nn.dropout(tf.nn.embedding_lookup(self.embed, self.responses_input), 0.8),
# lambda: tf.nn.embedding_lookup(self.embed, self.responses_input))
# build rnn_cell
cell_enc = tf.nn.rnn_cell.GRUCell(args.eh_size)
cell_ctx = tf.nn.rnn_cell.GRUCell(args.ch_size)
cell_dec = tf.nn.rnn_cell.GRUCell(args.dh_size)
# build encoder
with tf.variable_scope('encoder'):
# encoder_output: [batch*(num_turns-1), max_post_length, eh_size]
# encoder_state: [batch*(num_turns-1), eh_size]
encoder_output, encoder_state = tf.nn.dynamic_rnn(
cell_enc,
self.encoder_input,
self.posts_length,
dtype=tf.float32,
scope="encoder_rnn")
with tf.variable_scope('encoder', reuse=tf.AUTO_REUSE):
# prev_output: [batch, max_prev_length, eh_size]
prev_output, _ = tf.nn.dynamic_rnn(cell_enc,
tf.nn.embedding_lookup(
self.embed,
self.prev_posts),
self.prev_posts_length,
dtype=tf.float32,
scope="encoder_rnn")
# encoder_hidden_size = tf.shape(encoder_state)[-1]
with tf.variable_scope('context'):
# encoder_state_reshape: [batch, num_turns-1, eh_size]
# context_output: [batch, num_turns-1, ch_size]
# context_state: [batch, ch_size]
encoder_state_reshape = tf.reshape(
encoder_state, [-1, num_past_turns, args.eh_size])
context_output, self.context_state = tf.nn.dynamic_rnn(
cell_ctx,
encoder_state_reshape,
self.context_length,
dtype=tf.float32,
scope='context_rnn')
# get output projection function
output_fn = MyDense(data.vocab_size, use_bias=True)
sampled_sequence_loss = output_projection_layer(
args.dh_size, data.vocab_size, args.softmax_samples)
# construct helper and attention
train_helper = tf.contrib.seq2seq.TrainingHelper(
self.decoder_input, tf.maximum(self.responses_length, 1))
infer_helper = tf.contrib.seq2seq.GreedyEmbeddingHelper(
self.embed, tf.fill([batch_size], data.go_id), data.eos_id)
#encoder_len = tf.shape(encoder_output)[1]
#attention_memory = tf.reshape(encoder_output, [batch_size, -1, args.eh_size])
#attention_mask = tf.reshape(tf.sequence_mask(self.posts_length, encoder_len), [batch_size, -1])
'''
attention_memory = context_output
attention_mask = tf.reshape(tf.sequence_mask(self.context_length, self.num_turns - 1), [batch_size, -1])
'''
#attention_mask = tf.concat([tf.ones([batch_size, 1], tf.bool), attention_mask[:, 1:]], axis=1)
#attn_mechanism = MyAttention(args.dh_size, attention_memory, attention_mask)
# 注意这里的inputs，是最后一句话的编码，即[batch_size, prev_post_length, eh_size]
# 在attention中，如果query的维度和inputs不一致，需要先经过线性层将query转化为
attn_mechanism = tf.contrib.seq2seq.BahdanauAttention(
args.dh_size,
prev_output,
memory_sequence_length=tf.maximum(self.prev_posts_length, 1))
cell_dec_attn = tf.contrib.seq2seq.AttentionWrapper(
cell_dec, attn_mechanism, attention_layer_size=args.dh_size)
# 将posts的编码输出转化为解码器的维度 [batch, dh_size]
ctx_state_shaping = tf.layers.dense(self.context_state,
args.dh_size,
activation=None)
dec_start = cell_dec_attn.zero_state(
batch_size, dtype=tf.float32).clone(cell_state=ctx_state_shaping)
# build decoder (train)
with tf.variable_scope('decoder'):
decoder_train = tf.contrib.seq2seq.BasicDecoder(
cell_dec_attn, train_helper, dec_start)
train_outputs, _, _ = tf.contrib.seq2seq.dynamic_decode(
decoder_train, impute_finished=True, scope="decoder_rnn")
# 这里的decoder_output: [batch, decoder_length, dh_size]
self.decoder_output = train_outputs.rnn_output
# self.decoder_output = tf.nn.dropout(self.decoder_output, 0.8)
# decoder_distribution_teacher: [batch, decoder_length, vocab_size]
# decoder_loss: 标量
# decoder_all_loss: [batch, ]，表示每一句话的对数损失
self.decoder_distribution_teacher, self.decoder_loss, self.decoder_all_loss = \
sampled_sequence_loss(self.decoder_output, self.responses_target, self.decoder_mask)
# build decoder (test)
with tf.variable_scope('decoder', reuse=True):
decoder_infer = tf.contrib.seq2seq.BasicDecoder(
cell_dec_attn, infer_helper, dec_start, output_layer=output_fn)
infer_outputs, _, _ = tf.contrib.seq2seq.dynamic_decode(
decoder_infer,
impute_finished=True,
maximum_iterations=args.max_decoder_length,
scope="decoder_rnn")
# [batch, max_decoder_length, vocab_size]
self.decoder_distribution = infer_outputs.rnn_output
# 得到每一步解码的单词索引[batch, max_decoder_length]
self.generation_index = tf.argmax(
tf.split(self.decoder_distribution, [2, data.vocab_size - 2],
2)[1], 2) + 2 # for removing UNK
# 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.AdamOptimizer(self.learning_rate)
gradients = tf.gradients(self.decoder_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, data, args, embed):
# 这里的输入和前面的seq2seq一致
self.posts = tf.placeholder(tf.int32, (None, None),
'enc_inps') # batch*len
self.posts_length = tf.placeholder(tf.int32, (None, ),
'enc_lens') # batch
self.prevs_length = tf.placeholder(tf.int32, (None, ),
'enc_lens_prev') # batch
self.origin_responses = tf.placeholder(tf.int32, (None, None),
'dec_inps') # batch*len
self.origin_responses_length = tf.placeholder(tf.int32, (None, ),
'dec_lens') # batch
# kgs表示该样例所在这段对话中所有的知识：[batch, max_kg_nums, max_kg_length]
# kgs_h_length表示每一个知识中head entity的长度：[batch, max_kg_nums]
# kgs_hr_length表示每一个知识中head entity和relation的长度：[batch, max_kg_nums]
# kgs_hrt_length表示每一个知识中h,r,t的长度：[batch, max_kg_nums]
# kgs_index表示当前这句话实际使用的kg的索引指示矩阵：[batch, max_kg_nums]（其中使用的知识对应为1，没有使用的知识对应为0）
self.kgs = tf.placeholder(tf.int32, (None, None, None), 'kg_inps')
self.kgs_h_length = tf.placeholder(tf.int32, (None, None), 'kg_h_lens')
self.kgs_hr_length = tf.placeholder(tf.int32, (None, None),
'kg_hr_lens')
self.kgs_hrt_length = tf.placeholder(tf.int32, (None, None),
'kg_hrt_lens')
self.kgs_index = tf.placeholder(tf.float32, (None, None), 'kg_indices')
# 用来平衡解码损失和kg损失的超参数
self.lamb = tf.placeholder(tf.float32, name='lamb')
self.is_train = tf.placeholder(tf.bool)
# deal with original data to adapt encoder and decoder
# 获取解码器的输入和输出
batch_size, decoder_len = tf.shape(self.origin_responses)[0], tf.shape(
self.origin_responses)[1]
self.responses = tf.split(self.origin_responses, [1, decoder_len - 1],
1)[1] # no go_id
self.responses_length = self.origin_responses_length - 1
self.responses_input = tf.split(self.origin_responses,
[decoder_len - 1, 1],
1)[0] # no eos_id
self.responses_target = self.responses
decoder_len = decoder_len - 1
# 获取编码器的输入
self.posts_input = self.posts # batch*len
# 对解码器的mask矩阵，对于pad的mask
self.decoder_mask = tf.reshape(
tf.cumsum(tf.one_hot(self.responses_length - 1, decoder_len),
reverse=True,
axis=1), [-1, decoder_len])
kg_len = tf.shape(self.kgs)[2]
#kg_len = tf.Print(kg_len, [batch_size, kg_len, decoder_len, self.kgs_length])
# kg_h_mask = tf.reshape(tf.cumsum(tf.one_hot(self.kgs_h_length-1,
# kg_len), reverse=True, axis=2), [batch_size, -1, kg_len, 1])
# 这里分别得到对于key（也就是hr）的mask矩阵：[batch_size, max_kg_nums, max_kg_length, 1]
# 以及对于value（也就是t）的mask矩阵：[batch_size, max_kg_nums, max_kg_length, 1]
kg_hr_mask = tf.reshape(
tf.cumsum(tf.one_hot(self.kgs_hr_length - 1, kg_len),
reverse=True,
axis=2), [batch_size, -1, kg_len, 1])
kg_hrt_mask = tf.reshape(
tf.cumsum(tf.one_hot(self.kgs_hrt_length - 1, kg_len),
reverse=True,
axis=2), [batch_size, -1, kg_len, 1])
kg_key_mask = kg_hr_mask
kg_value_mask = kg_hrt_mask - kg_hr_mask
# 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 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)
# encoder_input: [batch, encoder_len, embed_size]
self.encoder_input = tf.nn.embedding_lookup(self.embed, self.posts)
# decoder_input: [batch, decoder_len, embed_size]
self.decoder_input = tf.nn.embedding_lookup(self.embed,
self.responses_input)
# kg_input: [batch, max_kg_nums, max_kg_length, embed_size]
self.kg_input = tf.nn.embedding_lookup(self.embed, self.kgs)
#self.encoder_input = tf.cond(self.is_train,
# lambda: tf.nn.dropout(tf.nn.embedding_lookup(self.embed, self.posts_input), 0.8),
# lambda: tf.nn.embedding_lookup(self.embed, self.posts_input)) #batch*len*unit
#self.decoder_input = tf.cond(self.is_train,
# lambda: tf.nn.dropout(tf.nn.embedding_lookup(self.embed, self.responses_input), 0.8),
# lambda: tf.nn.embedding_lookup(self.embed, self.responses_input))
# 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 = tf.nn.dynamic_rnn(
cell_enc,
self.encoder_input,
self.posts_length,
dtype=tf.float32,
scope="encoder_rnn")
# key对应一个知识h,r的词向量的均值 [batch, max_kg_nums, embed_size]
# value对应一个知识t的词向量的均值 [batch, max_kg_nums, embed_size]
self.kg_key_avg = tf.reduce_sum(
self.kg_input * kg_key_mask, axis=2) / tf.maximum(
tf.reduce_sum(kg_key_mask, axis=2),
tf.ones_like(tf.expand_dims(self.kgs_hrt_length, -1),
dtype=tf.float32))
self.kg_value_avg = tf.reduce_sum(
self.kg_input * kg_value_mask, axis=2) / tf.maximum(
tf.reduce_sum(kg_value_mask, axis=2),
tf.ones_like(tf.expand_dims(self.kgs_hrt_length, -1),
dtype=tf.float32))
# 将编码器的输出状态映射到embed_size的维度
# query: [batch, 1, embed_size]
with tf.variable_scope('knowledge'):
query = tf.reshape(
tf.layers.dense(tf.concat(encoder_state, axis=-1),
args.embedding_size,
use_bias=False),
[batch_size, 1, args.embedding_size])
# [batch, max_kg_nums]
kg_score = tf.reduce_sum(query * self.kg_key_avg, axis=2)
# 对于hrt大于0的位置（即该位置存在知识），取对应的kg_score，否则对应位置为-inf
kg_score = tf.where(tf.greater(self.kgs_hrt_length, 0), kg_score,
-tf.ones_like(kg_score) * np.inf)
# 计算每个知识对应的分数 [batch, max_kg_nums]
kg_alignment = tf.nn.softmax(kg_score)
# 根据计算的kg注意力分数的位置，计算关注的kg准确率和损失
kg_max = tf.argmax(kg_alignment, axis=-1)
kg_max_onehot = tf.one_hot(kg_max,
tf.shape(kg_alignment)[1],
dtype=tf.float32)
self.kg_acc = tf.reduce_sum(
kg_max_onehot * self.kgs_index) / tf.maximum(
tf.reduce_sum(tf.reduce_max(self.kgs_index, axis=-1)),
tf.constant(1.0))
self.kg_loss = tf.reduce_sum(
-tf.log(tf.clip_by_value(kg_alignment, 1e-12, 1.0)) *
self.kgs_index,
axis=1) / tf.maximum(tf.reduce_sum(self.kgs_index, axis=1),
tf.ones([batch_size], dtype=tf.float32))
self.kg_loss = tf.reduce_mean(self.kg_loss)
# 得到注意力之后的知识的嵌入：[batch, embed_size]
self.knowledge_embed = tf.reduce_sum(
tf.expand_dims(kg_alignment, axis=-1) * self.kg_value_avg, axis=1)
# 对维度进行扩充[batch, decoder_len, embed_size]
knowledge_embed_extend = tf.tile(
tf.expand_dims(self.knowledge_embed, axis=1), [1, decoder_len, 1])
# 将知识和原始的解码输入拼接，作为新的解码输入 [batch, decoder_len, 2*embed_size]
self.decoder_input = tf.concat(
[self.decoder_input, knowledge_embed_extend], axis=2)
# get output projection function
output_fn = MyDense(data.vocab_size, use_bias=True)
sampled_sequence_loss = output_projection_layer(
args.dh_size, data.vocab_size, args.softmax_samples)
encoder_len = tf.shape(encoder_output)[1]
posts_mask = tf.sequence_mask(self.posts_length, encoder_len)
prevs_mask = tf.sequence_mask(self.prevs_length, encoder_len)
attention_mask = tf.reshape(tf.logical_xor(posts_mask, prevs_mask),
[batch_size, encoder_len])
# construct helper and attention
train_helper = tf.contrib.seq2seq.TrainingHelper(
self.decoder_input, self.responses_length)
#infer_helper = tf.contrib.seq2seq.GreedyEmbeddingHelper(self.embed, tf.fill([batch_size], data.go_id), data.eos_id)
# 为了在推理的时候，每一次的输入都是上一次输出和知识的拼接
infer_helper = MyInferenceHelper(self.embed,
tf.fill([batch_size], data.go_id),
data.eos_id, self.knowledge_embed)
#attn_mechanism = tf.contrib.seq2seq.BahdanauAttention(args.dh_size, encoder_output,
# memory_sequence_length=self.posts_length)
# 这里的MyAttention主要解决BahdanauAttention只能输入编码序列长度的问题
attn_mechanism = MyAttention(args.dh_size, encoder_output,
attention_mask)
cell_dec_attn = tf.contrib.seq2seq.AttentionWrapper(
cell_dec, attn_mechanism, attention_layer_size=args.dh_size)
enc_state_shaping = tf.layers.dense(encoder_state,
args.dh_size,
activation=None)
dec_start = cell_dec_attn.zero_state(
batch_size, dtype=tf.float32).clone(cell_state=enc_state_shaping)
# build decoder (train)
with tf.variable_scope('decoder'):
decoder_train = tf.contrib.seq2seq.BasicDecoder(
cell_dec_attn, train_helper, dec_start)
train_outputs, _, _ = tf.contrib.seq2seq.dynamic_decode(
decoder_train, impute_finished=True, scope="decoder_rnn")
self.decoder_output = train_outputs.rnn_output
#self.decoder_output = tf.nn.dropout(self.decoder_output, 0.8)
# 输出概率分布和解码损失
self.decoder_distribution_teacher, self.decoder_loss, self.decoder_all_loss = \
sampled_sequence_loss(self.decoder_output, self.responses_target, self.decoder_mask)
# build decoder (test)
with tf.variable_scope('decoder', reuse=True):
decoder_infer = tf.contrib.seq2seq.BasicDecoder(
cell_dec_attn, infer_helper, dec_start, output_layer=output_fn)
infer_outputs, _, _ = tf.contrib.seq2seq.dynamic_decode(
decoder_infer,
impute_finished=True,
maximum_iterations=args.max_decoder_length,
scope="decoder_rnn")
# 输出解码概率分布
self.decoder_distribution = infer_outputs.rnn_output
self.generation_index = tf.argmax(
tf.split(self.decoder_distribution, [2, data.vocab_size - 2],
2)[1], 2) + 2 # for removing UNK
# 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.AdamOptimizer(self.learning_rate)
# 将解码损失和kg损失相加
self.loss = self.decoder_loss + self.lamb * self.kg_loss
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)
