这个系列网上的教程实在太多,所以我准备采用代码和理论相结合的方式,详细代码请点击我的github,基于python3.6和tensorflow1.4完成。数据都是合成数据,即构造一个输入任意序列encoder输出任意序列decoder的任务,比较简单,原理的基本实现。
基于tensorflow1.4 Seq2seq的实现
import helpers
import tensorflow as tf
from tensorflow.contrib import seq2seq,rnn
tf.__version__
'1.4.0'
tf.reset_default_graph()
sess = tf.InteractiveSession()
PAD = 0
EOS = 1
vocab_size = 10
input_embedding_size = 20
encoder_hidden_units = 25
decoder_hidden_units = encoder_hidden_units
import helpers as data_helpers
batch_size = 10
# 一个generator,每次产生一个minibatch的随机样本
batches = data_helpers.random_sequences(length_from=3, length_to=8,
vocab_lower=2, vocab_upper=10,
batch_size=batch_size)
print('产生%d个长度不一(最短3,最长8)的sequences, 其中前十个是:' % batch_size)
for seq in next(batches)[:min(batch_size, 10)]:
print(seq)
产生10个长度不一(最短3,最长8)的sequences, 其中前十个是:
[9, 4, 4, 6]
[4, 3, 3, 2]
[5, 7, 4, 4]
[5, 6, 6, 4, 6, 7, 3]
[6, 7, 5, 2, 8, 6, 8]
[5, 6, 9, 4, 6, 9, 6, 9]
[3, 5, 2, 2, 9]
[5, 6, 5, 8, 9, 8]
[6, 8, 2, 4, 3]
[9, 6, 8, 3, 5, 2]
1.使用seq2seq库实现seq2seq模型
tf.reset_default_graph()
sess = tf.InteractiveSession()
mode = tf.contrib.learn.ModeKeys.TRAIN
1. 计算图的数据的placeholder
with tf.name_scope('minibatch'):
encoder_inputs = tf.placeholder(tf.int32, [None, None], name='encoder_inputs')
encoder_inputs_length = tf.placeholder(tf.int32, [None], name='encoder_inputs_length')
decoder_targets = tf.placeholder(tf.int32, [None, None], name='decoder_targets')
decoder_inputs = tf.placeholder(shape=(None, None),dtype=tf.int32,name='decoder_inputs')
#decoder_inputs_length和decoder_targets_length是一样的
decoder_inputs_length = tf.placeholder(shape=(None,),
dtype=tf.int32,
name='decoder_inputs_length')
2.定义lstm cell 这里使用1层的lstm
def _create_rnn_cell():
def single_rnn_cell(encoder_hidden_units):
# 创建单个cell,这里需要注意的是一定要使用一个single_rnn_cell的函数,不然直接把cell放在MultiRNNCell
# 的列表中最终模型会发生错误
single_cell = rnn.LSTMCell(encoder_hidden_units)
#添加dropout
single_cell = rnn.DropoutWrapper(single_cell, output_keep_prob=0.5)
return single_cell
#列表中每个元素都是调用single_rnn_cell函数
#cell = rnn.MultiRNNCell([single_rnn_cell() for _ in range(self.num_layers)])
cell = rnn.MultiRNNCell([single_rnn_cell(encoder_hidden_units) for _ in range(1)])
return cell
dynamic_rnn
需要提供decoder_input
1.定义encoder 部分
with tf.variable_scope('encoder'):
# 创建LSTMCell
encoder_cell = _create_rnn_cell()
# 构建embedding矩阵,encoder和decoder公用该词向量矩阵
embedding = tf.get_variable('embedding', [vocab_size,input_embedding_size])
encoder_inputs_embedded = tf.nn.embedding_lookup(embedding,encoder_inputs)
# 使用dynamic_rnn构建LSTM模型,将输入编码成隐层向量。
# encoder_outputs用于attention,batch_size*encoder_inputs_length*rnn_size,
# encoder_state用于decoder的初始化状态,batch_size*rnn_szie
encoder_outputs, encoder_state = tf.nn.dynamic_rnn(encoder_cell, encoder_inputs_embedded,
sequence_length=encoder_inputs_length,
dtype=tf.float32)
2.定义decoder 部分(暂时不添加attention部分)
with tf.variable_scope('decoder'):
decoder_cell = _create_rnn_cell()
#定义decoder的初始状态
decoder_initial_state = encoder_state
#定义output_layer
output_layer = tf.layers.Dense(vocab_size,kernel_initializer=tf.truncated_normal_initializer(mean=0.0, stddev=0.1))
decoder_inputs_embedded = tf.nn.embedding_lookup(embedding, decoder_inputs)
# 训练阶段,使用TrainingHelper+BasicDecoder的组合,这一般是固定的,当然也可以自己定义Helper类,实现自己的功能
training_helper = seq2seq.TrainingHelper(inputs=decoder_inputs_embedded,
sequence_length=decoder_inputs_length,
time_major=False, name='training_helper')
training_decoder = seq2seq.BasicDecoder(cell=decoder_cell, helper=training_helper,
initial_state=decoder_initial_state,
output_layer=output_layer)
# 调用dynamic_decode进行解码,decoder_outputs是一个namedtuple,里面包含两项(rnn_outputs, sample_id)
# rnn_output: [batch_size, decoder_targets_length, vocab_size],保存decode每个时刻每个单词的概率,可以用来计算loss
# sample_id: [batch_size], tf.int32,保存最终的编码结果。可以表示最后的答案
max_target_sequence_length = tf.reduce_max(decoder_inputs_length, name='max_target_len')
decoder_outputs, _, _ = seq2seq.dynamic_decode(decoder=training_decoder,
impute_finished=True,
maximum_iterations=max_target_sequence_length)
#创建一个与decoder_outputs.rnn_output一样的tensor给decoder_logits_train
decoder_logits_train = tf.identity(decoder_outputs.rnn_output)
sample_id = decoder_outputs.sample_id
#decoder_predict_train = tf.argmax(decoder_logits_train, axis=-1,name='decoder_pred_train')
#decoder_predict_decode = tf.expand_dims(decoder_outputs.sample_id, -1)
# 根据目标序列长度,选出其中最大值,然后使用该值构建序列长度的mask标志。用一个sequence_mask的例子来说明起作用
# tf.sequence_mask([1, 3, 2], 5)
# [[True, False, False, False, False],
# [True, True, True, False, False],
# [True, True, False, False, False]]
max_target_sequence_length = tf.reduce_max(decoder_inputs_length, name='max_target_len')
mask = tf.sequence_mask(decoder_inputs_length,max_target_sequence_length, dtype=tf.float32, name='masks')
print('\t%s' % repr(decoder_logits_train))
print('\t%s' % repr(decoder_targets))
print('\t%s' % repr(sample_id))
loss = seq2seq.sequence_loss(logits=decoder_logits_train,targets=decoder_targets, weights=mask)
<tf.Tensor 'decoder/Identity:0' shape=(?, ?, 10) dtype=float32>
<tf.Tensor 'minibatch/decoder_targets:0' shape=(?, ?) dtype=int32>
<tf.Tensor 'decoder/decoder/transpose_1:0' shape=(?, ?) dtype=int32>
train_op = tf.train.AdamOptimizer(learning_rate = 0.001).minimize(loss)
sess.run(tf.global_variables_initializer())
def next_feed():
batch = next(batches)
encoder_inputs_, encoder_inputs_length_ = data_helpers.batch(batch)
decoder_targets_, decoder_targets_length_ = data_helpers.batch(
[(sequence) + [EOS] for sequence in batch]
)
decoder_inputs_, decoder_inputs_length_ = data_helpers.batch(
[[EOS] + (sequence) for sequence in batch]
)
# 在feedDict里面,key可以是一个Tensor
return {
encoder_inputs: encoder_inputs_.T,
decoder_inputs: decoder_inputs_.T,
decoder_targets: decoder_targets_.T,
encoder_inputs_length: encoder_inputs_length_,
decoder_inputs_length: decoder_inputs_length_
}
x = next_feed()
print('encoder_inputs:')
print(x[encoder_inputs][0,:])
print('encoder_inputs_length:')
print(x[encoder_inputs_length][0])
print('decoder_inputs:')
print(x[decoder_inputs][0,:])
print('decoder_inputs_length:')
print(x[decoder_inputs_length][0])
print('decoder_targets:')
print(x[decoder_targets][0,:])
encoder_inputs:
[9 4 3 3 2 6 0 0]
encoder_inputs_length:
6
decoder_inputs:
[1 9 4 3 3 2 6 0 0]
decoder_inputs_length:
7
decoder_targets:
[9 4 3 3 2 6 1 0 0]
loss_track = []
max_batches = 3001
batches_in_epoch = 100
try:
# 一个epoch的learning
for batch in range(max_batches):
fd = next_feed()
_, l = sess.run([train_op, loss], fd)
loss_track.append(l)
if batch == 0 or batch % batches_in_epoch == 0:
print('batch {}'.format(batch))
print(' minibatch loss: {}'.format(sess.run(loss, fd)))
predict_ = sess.run(decoder_outputs.sample_id, fd)
for i, (inp, pred) in enumerate(zip(fd[encoder_inputs], predict_)):
print(' sample {}:'.format(i + 1))
print(' input > {}'.format(inp))
print(' predicted > {}'.format(pred))
if i >= 2:
break
print()
except KeyboardInterrupt:
print('training interrupted')
batch 0
minibatch loss: 2.2938551902770996
sample 1:
input > [8 5 3 9 3 5 0 0]
predicted > [4 4 4 4 4 1 4 0 0]
sample 2:
input > [9 5 8 4 4 6 4 7]
predicted > [9 3 4 4 4 9 9 4 9]
sample 3:
input > [6 6 5 7 6 8 0 0]
predicted > [1 4 4 3 3 3 4 0 0]
batch 100
minibatch loss: 2.1440541744232178
sample 1:
input > [5 5 3 7 2 5 0 0]
predicted > [7 5 5 5 5 7 1 0 0]
sample 2:
input > [3 2 7 2 4 9 6 8]
predicted > [2 2 2 2 2 1 1 1 1]
sample 3:
input > [6 8 6 2 0 0 0 0]
predicted > [2 9 2 1 1 0 0 0 0]
batch 200
minibatch loss: 1.7902907133102417
sample 1:
input > [8 5 6 9 6 6 7 0]
predicted > [7 5 7 9 5 7 5 1 0]
sample 2:
input > [5 3 4 0 0 0 0 0]
predicted > [5 3 1 1 0 0 0 0 0]
sample 3:
input > [8 9 3 6 6 4 6 2]
predicted > [6 9 8 4 4 4 2 1 1]
batch 300
minibatch loss: 1.6711502075195312
sample 1:
input > [6 5 6 5 7 0 0 0]
predicted > [7 7 7 7 5 1 0 0 0]
sample 2:
input > [7 8 6 9 7 2 7 0]
predicted > [5 7 7 5 7 7 7 1 0]
sample 3:
input > [7 3 8 2 2 0 0 0]
predicted > [2 2 2 2 1 1 0 0 0]
batch 400
minibatch loss: 1.4671175479888916
sample 1:
input > [3 4 8 8 9 0 0 0]
predicted > [4 8 8 4 2 1 0 0 0]
sample 2:
input > [5 2 6 2 5 4 3 8]
predicted > [8 8 2 6 2 9 8 8 1]
sample 3:
input > [2 9 6 0 0 0 0 0]
predicted > [8 6 5 1 0 0 0 0 0]
batch 500
minibatch loss: 1.3590279817581177
sample 1:
input > [3 2 2 3 8 8 5 5]
predicted > [8 8 8 9 5 5 5 1 1]
sample 2:
input > [8 4 6 3 8 2 0 0]
predicted > [4 4 2 8 2 4 1 0 0]
sample 3:
input > [2 2 6 3 9 9 0 0]
predicted > [4 2 2 9 6 6 1 0 0]
batch 600
minibatch loss: 1.292779564857483
sample 1:
input > [7 9 6 5 0 0 0 0]
predicted > [5 9 5 5 1 0 0 0 0]
sample 2:
input > [5 9 3 0 0 0 0 0]
predicted > [5 9 3 1 0 0 0 0 0]
sample 3:
input > [3 3 8 5 6 3 0 0]
predicted > [3 3 3 3 9 3 1 0 0]
batch 700
minibatch loss: 1.2727009057998657
sample 1:
input > [4 4 7 7 8 6 5 7]
predicted > [3 7 7 7 9 7 5 1 1]
sample 2:
input > [5 4 2 2 7 7 0 0]
predicted > [2 2 8 7 7 7 1 0 0]
sample 3:
input > [7 3 9 7 8 0 0 0]
predicted > [3 7 5 7 8 1 0 0 0]
batch 800
minibatch loss: 1.1580817699432373
sample 1:
input > [8 3 2 7 8 5 7 0]
predicted > [4 3 7 7 7 7 7 1 0]
sample 2:
input > [2 8 7 6 7 2 0 0]
predicted > [2 2 7 7 7 2 1 0 0]
sample 3:
input > [8 7 8 4 3 2 5 8]
predicted > [8 7 4 3 5 5 5 8 1]
batch 900
minibatch loss: 1.1622250080108643
sample 1:
input > [6 8 2 5 5 0 0 0]
predicted > [8 8 5 5 5 1 0 0 0]
sample 2:
input > [5 9 4 5 7 0 0 0]
predicted > [5 6 7 7 7 1 0 0 0]
sample 3:
input > [6 2 3 4 9 5 3 9]
predicted > [4 3 3 4 9 3 9 6 1]
batch 1000
minibatch loss: 1.2378357648849487
sample 1:
input > [4 3 2 3 8 7 4 8]
predicted > [3 4 8 3 2 4 2 2 1]
sample 2:
input > [5 6 5 4 5 8 5 6]
predicted > [5 5 5 5 5 5 6 6 1]
sample 3:
input > [3 8 4 3 4 3 6 0]
predicted > [2 4 4 4 4 3 6 1 0]
batch 1100
minibatch loss: 1.1085090637207031
sample 1:
input > [4 7 2 0 0 0 0 0]
predicted > [4 2 8 1 0 0 0 0 0]
sample 2:
input > [6 2 3 5 7 7 2 4]
predicted > [6 7 7 7 7 7 2 4 1]
sample 3:
input > [9 7 7 3 5 2 4 0]
predicted > [7 7 7 3 5 8 3 1 0]
batch 1200
minibatch loss: 1.1771703958511353
sample 1:
input > [8 2 7 8 9 7 0 0]
predicted > [8 8 5 8 7 7 1 0 0]
sample 2:
input > [8 8 4 7 2 8 0 0]
predicted > [8 8 2 2 2 2 1 0 0]
sample 3:
input > [2 9 7 9 4 9 3 2]
predicted > [9 9 7 8 4 8 3 2 1]
batch 1300
minibatch loss: 0.9447832107543945
sample 1:
input > [4 3 2 3 9 6 0 0]
predicted > [4 3 4 6 9 9 1 0 0]
sample 2:
input > [5 9 4 0 0 0 0 0]
predicted > [5 6 4 1 0 0 0 0 0]
sample 3:
input > [8 8 8 2 7 8 0 0]
predicted > [8 8 8 2 5 8 1 0 0]
batch 1400
minibatch loss: 1.0269840955734253
sample 1:
input > [5 6 3 5 7 5 6 4]
predicted > [2 6 5 5 7 6 6 4 1]
sample 2:
input > [2 6 2 4 2 6 0 0]
predicted > [2 4 2 6 6 6 1 0 0]
sample 3:
input > [2 3 8 4 0 0 0 0]
predicted > [4 3 8 4 1 0 0 0 0]
batch 1500
minibatch loss: 0.8967496752738953
sample 1:
input > [7 7 8 6 4 7 0 0]
predicted > [7 7 2 4 4 7 1 0 0]
sample 2:
input > [7 8 4 6 0 0 0 0]
predicted > [7 4 4 6 1 0 0 0 0]
sample 3:
input > [6 7 5 6 8 7 7 6]
predicted > [7 7 5 6 7 7 7 1 1]
batch 1600
minibatch loss: 0.9586960077285767
sample 1:
input > [6 5 8 3 2 4 9 0]
predicted > [5 5 8 4 2 4 5 1 0]
sample 2:
input > [4 9 6 9 0 0 0 0]
predicted > [3 9 9 9 1 0 0 0 0]
sample 3:
input > [7 7 9 9 5 2 0 0]
predicted > [7 5 9 5 5 2 1 0 0]
batch 1700
minibatch loss: 1.0395662784576416
sample 1:
input > [5 7 4 5 0 0 0 0]
predicted > [5 7 4 7 1 0 0 0 0]
sample 2:
input > [3 3 2 8 0 0 0 0]
predicted > [3 4 2 8 1 0 0 0 0]
sample 3:
input > [6 8 2 7 8 5 0 0]
predicted > [8 8 2 7 8 7 1 0 0]
batch 1800
minibatch loss: 0.9203397035598755
sample 1:
input > [4 5 4 2 5 8 0 0]
predicted > [4 5 4 5 5 1 1 0 0]
sample 2:
input > [2 7 4 8 8 4 0 0]
predicted > [7 7 4 8 4 4 1 0 0]
sample 3:
input > [6 6 4 0 0 0 0 0]
predicted > [6 6 4 1 0 0 0 0 0]
batch 1900
minibatch loss: 0.7155815362930298
sample 1:
input > [6 5 2 2 9 7 9 0]
predicted > [6 2 2 8 9 7 9 1 0]
sample 2:
input > [5 6 2 9 9 4 8 0]
predicted > [5 9 9 6 9 4 8 1 0]
sample 3:
input > [6 8 2 9 0 0 0 0]
predicted > [2 8 2 9 1 0 0 0 0]
batch 2000
minibatch loss: 0.7423955202102661
sample 1:
input > [3 5 2 9 8 5 3 2]
predicted > [5 5 2 3 5 2 3 2 1]
sample 2:
input > [8 5 5 9 6 0 0 0]
predicted > [5 9 5 6 6 1 0 0 0]
sample 3:
input > [6 8 8 0 0 0 0 0]
predicted > [8 8 8 1 0 0 0 0 0]
batch 2100
minibatch loss: 0.8510919213294983
sample 1:
input > [7 7 9 0 0 0 0 0]
predicted > [7 7 9 1 0 0 0 0 0]
sample 2:
input > [4 2 9 2 5 6 2 6]
predicted > [2 2 9 2 6 6 6 6 1]
sample 3:
input > [4 6 8 2 5 5 0 0]
predicted > [6 9 8 2 5 5 1 0 0]
batch 2200
minibatch loss: 0.6667694449424744
sample 1:
input > [9 8 8 4 0 0 0 0]
predicted > [8 8 8 4 1 0 0 0 0]
sample 2:
input > [5 8 7 0 0 0 0 0]
predicted > [2 8 1 1 0 0 0 0 0]
sample 3:
input > [9 3 4 0 0 0 0 0]
predicted > [3 3 4 1 0 0 0 0 0]
batch 2300
minibatch loss: 0.7337868809700012
sample 1:
input > [2 4 7 6 6 9 0 0]
predicted > [2 6 6 6 6 9 1 0 0]
sample 2:
input > [3 5 2 8 0 0 0 0]
predicted > [3 5 2 8 1 0 0 0 0]
sample 3:
input > [5 5 8 4 8 9 4 3]
predicted > [3 5 8 4 4 3 3 3 1]
batch 2400
minibatch loss: 0.8720135688781738
sample 1:
input > [8 7 5 7 2 7 2 0]
predicted > [2 5 5 7 2 7 8 1 0]
sample 2:
input > [7 7 9 4 3 6 8 0]
predicted > [7 7 9 4 3 9 7 1 0]
sample 3:
input > [8 6 3 2 6 0 0 0]
predicted > [2 6 2 2 6 1 0 0 0]
batch 2500
minibatch loss: 0.6776264309883118
sample 1:
input > [7 7 8 8 8 3 2 0]
predicted > [7 7 8 8 8 3 1 1 0]
sample 2:
input > [6 7 7 9 3 7 9 8]
predicted > [7 7 7 3 9 7 9 8 1]
sample 3:
input > [8 6 6 7 0 0 0 0]
predicted > [6 6 6 7 1 0 0 0 0]
batch 2600
minibatch loss: 0.7246588468551636
sample 1:
input > [3 6 7 0 0 0 0 0]
predicted > [6 6 7 1 0 0 0 0 0]
sample 2:
input > [9 6 8 4 6 6 8 0]
predicted > [6 6 8 6 6 6 8 1 0]
sample 3:
input > [6 5 9 6 9 2 7 0]
predicted > [6 9 9 4 6 2 6 1 0]
batch 2700
minibatch loss: 0.6910533308982849
sample 1:
input > [3 7 4 0 0 0 0 0]
predicted > [3 7 4 1 0 0 0 0 0]
sample 2:
input > [2 6 9 9 7 3 2 5]
predicted > [6 6 9 3 3 3 2 5 1]
sample 3:
input > [9 6 5 0 0 0 0 0]
predicted > [9 6 5 1 0 0 0 0 0]
batch 2800
minibatch loss: 0.6767545342445374
sample 1:
input > [9 8 5 0 0 0 0]
predicted > [9 8 5 1 0 0 0 0]
sample 2:
input > [2 6 6 4 9 8 2]
predicted > [2 6 6 4 8 8 2 9]
sample 3:
input > [3 8 7 0 0 0 0]
predicted > [3 8 7 1 0 0 0 0]
batch 2900
minibatch loss: 0.6852056980133057
sample 1:
input > [6 4 7 0 0 0 0 0]
predicted > [6 4 7 1 0 0 0 0 0]
sample 2:
input > [9 3 9 9 0 0 0 0]
predicted > [3 9 9 9 1 0 0 0 0]
sample 3:
input > [3 5 8 0 0 0 0 0]
predicted > [3 5 8 1 0 0 0 0 0]
batch 3000
minibatch loss: 0.6660669445991516
sample 1:
input > [7 2 6 9 5 2 8 7]
predicted > [7 2 9 5 5 2 7 5 1]
sample 2:
input > [6 9 9 3 2 0 0 0]
predicted > [9 9 9 3 5 1 0 0 0]
sample 3:
input > [8 4 6 6 0 0 0 0]
predicted > [8 4 6 6 1 0 0 0 0]