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model.py
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# -*- coding: utf-8 -*-
# @Time : 2019/3/19 16:21
# @Author : Alan
# @Email : xiezhengwen2013@163.com
# @File : model.py
# @Software: PyCharm
import tensorflow as tf
from model_utils import *
from tensorflow.contrib import rnn
class MAN(object):
def __init__(self, config):
self.ques_len = config.ques_length
self.ans_len = config.ans_length
self.hidden_size = config.hidden_size
self.output_size = config.output_size
self.rnn_size = config.rnn_size
self.learning_rate = config.learning_rate
self.optimizer = config.optimizer
self.l2_lambda = config.l2_lambda
self.clip_value = config.clip_value
self.embeddings = config.embeddings
self.window_sizes = config.window_sizes
self.n_filters = config.n_filters
self.margin = config.margin
self.num_steps = config.num_steps
self.layer_size = config.layer_size
self._placeholder_init_pointwise()
self._initialize_weights()
self.q_a_cosine, self.q_aneg_cosine = self._build(self.embeddings)
# 损失和精确度
self.total_loss, self.accu = self._add_loss_op(self.q_a_cosine, self.q_aneg_cosine, self.l2_lambda)
# 训练节点
self.train_op = self._add_train_op(self.total_loss)
def _placeholder_init_pointwise(self):
self._ques = tf.placeholder(tf.int32, [None, self.ques_len], name='ques_point')
self._ans = tf.placeholder(tf.int32, [None, self.ans_len], name='ans_point')
self._ans_neg = tf.placeholder(tf.int32, [None, self.ans_len], name='ans_point')
self._ques_mask = tf.placeholder(tf.int32, [None], 'ques_mask')
self._ans_mask = tf.placeholder(tf.int32, [None], 'ans_mask')
self._ans_neg_mask = tf.placeholder(tf.int32, [None], 'ans_neg_mask')
self.dropout_keep_prob = tf.placeholder(tf.float32, name="dropout_keep_prob")
self.batch_size, self.list_size = tf.shape(self._ans)[0], tf.shape(self._ans)[1]
def _initialize_weights(self):
self.W_q1 = weight_variable('W_q1', [2 * self.rnn_size, 2*self.rnn_size])
self.W_m1 = weight_variable('W_m1', [2 * self.rnn_size, 2 * self.rnn_size])
self.W_s1 = weight_variable('W_s1', [2 * self.rnn_size, 1])
self.W_q2 = weight_variable('W_q2', [2 * self.rnn_size, 2*self.rnn_size])
self.W_m2 = weight_variable('W_m2', [2 * self.rnn_size, 2 * self.rnn_size])
self.W_s2 = weight_variable('W_s2', [2 * self.rnn_size, 1])
self.W_q3 = weight_variable('W_q3', [2 * self.rnn_size, 2*self.rnn_size])
self.W_m3 = weight_variable('W_m3', [2 * self.rnn_size, 2 * self.rnn_size])
self.W_s3 = weight_variable('W_s3', [2 * self.rnn_size, 1])
def _bilstm_layer(self, inputs, rnn_size, seq_len, layer_size, batch_size, keep_prob, scope, reuse=False):
"""
双向LSTM
"""
with tf.variable_scope(scope, reuse=reuse):
def cell():
lstm_cell = rnn.LSTMCell(num_units=rnn_size)
lstm_cell = rnn.DropoutWrapper(lstm_cell, output_keep_prob=keep_prob) ##
return lstm_cell
cell_bw = cell_fw = tf.nn.rnn_cell.MultiRNNCell([cell() for _ in range(layer_size)])
cell_fw_initial = cell_fw.zero_state(batch_size, tf.float32)
cell_bw_initial = cell_bw.zero_state(batch_size, tf.float32)
output = tf.nn.bidirectional_dynamic_rnn(cell_fw=cell_fw,
cell_bw=cell_bw,
inputs=inputs,
initial_state_fw=cell_fw_initial,
initial_state_bw=cell_bw_initial,
sequence_length=seq_len,
dtype=tf.float32)
return output
def _multihop_layer(self, q):
with tf.variable_scope("MultihopAttention_layer", reuse=False):
'''
主要是为了更新o_q(k)
1. o_q[0] = sum(h_q(t)) / l
2. m_q[0] = sum(h_q(t)) / l
3. M = tanh(W_q(k).h_q(t))
4. N = tanh(W_m(k).m_q(k-1))
5. s_t = tanh(W_q(k).h_q(t)) * tanh(W_m(k).m_q(k-1))
6. w = w_s(k).s_t(k)
7. alpha_t = softmax(w_s(k).s_t(k))
8. o_q[1] = sum( alpha_t * h_q(t))
'''
# num_steps = 1的情况
m_q = [None] * self.num_steps
m_q[0] = tf.reduce_mean(q, axis=1) # (bz, 2hz)
o_q = [None] * (self.num_steps + 1)
o_q[0] = tf.reduce_mean(q, axis=1) # (bz, 2hz)
M = tf.tanh(multiply_3_2(q, self.W_q1)) # (bz, len, 2hz)
N = tf.expand_dims(tf.tanh(tf.matmul(m_q[0], self.W_m1)), axis=1) # (bz, 1, 2hz)
s_t = tf.multiply(M, N) # (bz, len, 2hz)
w = multiply_3_2(s_t, self.W_s1) # (bz, len, 1)
alpha_t = tf.nn.softmax(w, axis=1) # (bz, len, 1)
o_q[1] = tf.reduce_sum(tf.multiply(q, alpha_t), axis=1) # (bz, 2hz)
if self.num_steps > 1: # num_steps = 2的情况
m_q[1] = m_q[0] + o_q[1] # (bz, 2hz)
M = tf.tanh(multiply_3_2(q, self.W_q2)) # (bz, len, 2hz)
N = tf.expand_dims(tf.tanh(tf.matmul(m_q[1], self.W_m2)), axis=1) # (bz, 1, 2hz)
s_t = tf.multiply(M, N) # (bz, len, 2hz)
w = multiply_3_2(s_t, self.W_s2) # (bz, len, 1)
alpha_t = tf.nn.softmax(w, axis=1) # (bz, len, 1)
o_q[2] = tf.reduce_sum(tf.multiply(q, alpha_t), axis=1) # (bz, 2hz)
if self.num_steps > 2: # num_steps = 3的情况
m_q[2] = m_q[1] + o_q[2] # (bz, 2hz)
M = tf.tanh(multiply_3_2(q, self.W_q3)) # (bz, len, 2hz)
N = tf.expand_dims(tf.tanh(tf.matmul(m_q[2], self.W_m3)), axis=1) # (bz, 1, 2hz)
s_t = tf.multiply(M, N) # (bz, len, 2hz)
w = multiply_3_2(s_t, self.W_s3) # (bz, len, 1)
alpha_t = tf.nn.softmax(w, axis=1) # (bz, len, 1)
o_q[3] = tf.reduce_sum(tf.multiply(q, alpha_t), axis=1) # (bz, 2hz)
return o_q
def _sequential_layer(self, inputs1, inputs2, ans_mask, rnn_size, batch_size, seq_len, dropout_keep_prob, index,
isreuse = False):
"""
论文地址：
.代表矩阵乘法
1. Gama = Gama_1 = j *W.h_i
2. outputs_n = n_i = GRU(n_i, gama_i)
3. n_ = n_i = concat(n_i, n_i)
4. alpha = alpha_i = softmax(1(T).n_i)
5. partial_bilinear_output = O = sum(alpha * h_)
6. pred = a = argmax(M_a.O) 在本模型中，这一步取消
"""
j = tf.expand_dims(inputs1, axis=1) # (bz, 1, 2hz)
h = inputs2 # (bz, len, 2hz)
# W_h = tf.matmul(h, self.W)
Gama = tf.multiply(j, h) # (bz, len, 2hz)
print_shape('Gama', Gama)
outputs_n, finalState_n = self._bilstm_layer(Gama, rnn_size, seq_len, 1, batch_size, 1.0,
'sequentional_attention_{}'.format(index), reuse=isreuse)
n_ = tf.concat(outputs_n, axis=2) # (bz, len, 2hz)
alpha = tf.nn.softmax(tf.reduce_sum(n_, axis=2), axis=-1) # (bz, len)
# 将句子padding部分权重消除
# alpha = tf.expand_dims(tf.multiply(alpha, ans_mask), axis=-1)
alpha = tf.expand_dims(alpha, axis=-1)
partial_bilinear_output = tf.reduce_sum(tf.multiply(alpha, h), axis=1) # (bz, 2hz)
print_shape('SequentialAttention_output', partial_bilinear_output)
return partial_bilinear_output
def _match_layer(self, q, a_pos, a_neg, p_mask, n_mask, rnn_size, batch_size, p_seq_len, n_seq_len, dropout_keep_prob):
for i in range(self.num_steps+1):
pos = self._sequential_layer(q[i], a_pos, p_mask, rnn_size, batch_size, p_seq_len, dropout_keep_prob, i+1,
isreuse=False)
neg = self._sequential_layer(q[i], a_neg, n_mask, rnn_size, batch_size, n_seq_len, dropout_keep_prob, i+1,
isreuse=True)
q_ = tf.nn.l2_normalize(q[i], dim=1)
as_pos = tf.nn.l2_normalize(pos, dim=1)
as_neg = tf.nn.l2_normalize(neg, dim=1)
q_pos_cosine = tf.reduce_sum(tf.multiply(q_, as_pos), 1)
q_neg_cosine = tf.reduce_sum(tf.multiply(q_, as_neg), 1)
sim_pos = q_pos_cosine if i == 0 else sim_pos + q_pos_cosine
sim_neg = q_neg_cosine if i == 0 else sim_neg + q_neg_cosine
return sim_pos, sim_neg
def _build(self, embeddings, rnn_type = 'lstm'):
self.Embedding = tf.Variable(tf.to_float(embeddings), trainable=False, name='Embedding')
self.q_embed = tf.nn.dropout(tf.nn.embedding_lookup(self.Embedding, self._ques), keep_prob=self.dropout_keep_prob)
self.a_embed = tf.nn.dropout(tf.nn.embedding_lookup(self.Embedding, self._ans), keep_prob=self.dropout_keep_prob)
self.a_neg_embed = tf.nn.dropout(tf.nn.embedding_lookup(self.Embedding, self._ans_neg), keep_prob=self.dropout_keep_prob)
q_mask = tf.sequence_mask(self._ques_mask, self.ques_len, dtype=tf.float32)
a_mask = tf.sequence_mask(self._ans_mask, self.ans_len, dtype=tf.float32)
a_neg_mask = tf.sequence_mask(self._ans_neg_mask, self.ans_len, dtype=tf.float32)
# 上下文编码
if rnn_type == 'lstm':
q_outputs, q_final_state = self._bilstm_layer(self.q_embed, self.rnn_size, self._ques_mask, self.layer_size,
self.batch_size, self.dropout_keep_prob, 'lstm')
a_outputs, a_final_state = self._bilstm_layer(self.a_embed, self.rnn_size, self._ans_mask, self.layer_size,
self.batch_size, self.dropout_keep_prob, 'lstm',
reuse=True)
a_neg_outputs, a_neg_final_state = self._bilstm_layer(self.a_embed, self.rnn_size, self._ans_neg_mask,
self.layer_size, self.batch_size,
self.dropout_keep_prob, 'lstm', reuse=True)
elif rnn_type == 'gru':
q_outputs, q_final_state = self._bilstm_layer(self.q_embed, self.rnn_size, self._ques_mask, self.layer_size,
self.batch_size, self.dropout_keep_prob, 'gru')
a_outputs, a_final_state = self._bilstm_layer(self.a_embed, self.rnn_size, self._ans_mask, self.layer_size,
self.batch_size, self.dropout_keep_prob, 'gru',
reuse=True)
a_neg_outputs, a_neg_final_state = self._bilstm_layer(self.a_embed, self.rnn_size, self._ans_neg_mask,
self.layer_size, self.batch_size,
self.dropout_keep_prob, 'gru', reuse=True)
rnn_q = tf.concat(q_outputs, axis=-1)
rnn_a = tf.concat(a_outputs, axis=-1)
rnn_a_neg = tf.concat(a_neg_outputs, axis=-1)
o_q = self._multihop_layer(rnn_q)
sim_pos, sim_neg = self._match_layer(o_q, rnn_a, rnn_a_neg, a_mask, a_neg_mask, self.rnn_size, self.batch_size,
self._ans_mask, self._ans_neg_mask, self.dropout_keep_prob)
return sim_pos, sim_neg
def _margin_loss(self, pos_sim, neg_sim):
original_loss = self.margin - pos_sim + neg_sim
l = tf.maximum(tf.zeros_like(original_loss), original_loss)
loss = tf.reduce_sum(l)
return loss, l
def _add_loss_op(self, p_sim, n_sim, l2_lambda=0.0001):
"""
损失节点
"""
loss, l = self._margin_loss(p_sim, n_sim)
accu = tf.reduce_mean(tf.cast(tf.equal(0., l), tf.float32))
reg_losses = tf.get_collection(tf.GraphKeys.REGULARIZATION_LOSSES)
l2_loss = sum(reg_losses) * l2_lambda
pairwise_loss = loss + l2_loss
tf.summary.scalar('pairwise_loss', pairwise_loss)
self.summary_op = tf.summary.merge_all()
return pairwise_loss, accu
def _add_train_op(self, loss):
"""
训练节点
"""
with tf.name_scope('train_op'):
# 记录训练步骤
self.global_step = tf.Variable(0, name='global_step', trainable=False)
opt = tf.train.AdamOptimizer(self.learning_rate)
# train_op = opt.minimize(loss, self.global_step)
gradients, v = zip(*opt.compute_gradients(loss))
clip_gradients = gradients
if self.clip_value is not None:
clip_gradients, _ = tf.clip_by_global_norm(gradients, self.clip_value)
train_op = opt.apply_gradients(zip(clip_gradients, v), global_step= self.global_step)
return train_op