/
tf_lstm.py
276 lines (227 loc) · 11.8 KB
/
tf_lstm.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
# Customized LSTM Cell
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import collections
import math
import numpy as np
import tensorflow as tf
from tensorflow.python.framework import ops
from tensorflow.python.framework import tensor_shape
from tensorflow.python.ops import array_ops
from tensorflow.python.ops import clip_ops
from tensorflow.python.ops import embedding_ops
from tensorflow.python.ops import init_ops
from tensorflow.python.ops import math_ops
from tensorflow.python.ops import nn_ops
from tensorflow.python.ops import variable_scope as vs
from tensorflow.python.ops.math_ops import sigmoid
from tensorflow.python.ops.math_ops import tanh
from tensorflow.python.ops.init_ops import constant_initializer
from tensorflow.python.platform import tf_logging as logging
from tensorflow.python.ops.rnn_cell import RNNCell
from tensorflow.python.ops.rnn_cell import LSTMStateTuple
from tensorflow.python.ops.rnn_cell import _get_concat_variable
from tensorflow.python.ops.rnn_cell import _get_sharded_variable
from tensorflow.python.ops.nn import batch_normalization, moments
from tensorflow.python.training.moving_averages import ExponentialMovingAverage
from tensorflow.python.ops.control_flow_ops import cond
_LSTMStateTuple = collections.namedtuple("LSTMStateTuple", ("c", "h"))
def batch_norm(x, deterministic, alpha=0.9, shift=True, scope='bn'):
with vs.variable_scope(scope):
dtype = x.dtype
input_shape = x.get_shape().as_list()
feat_dim = input_shape[-1]
axes = range(len(input_shape)-1)
if shift:
beta = vs.get_variable(
scope+"_beta", shape=[feat_dim],
initializer=init_ops.zeros_initializer, dtype=dtype)
else:
beta = vs.get_variable(
scope+"_beta", shape=[feat_dim],
initializer=init_ops.zeros_initializer,
dtype=dtype, trainable=False)
gamma = vs.get_variable(
scope+"_gamma", shape=[feat_dim],
initializer=init_ops.constant_initializer(0.1), dtype=dtype)
mean = vs.get_variable(scope+"_mean", shape=[feat_dim],
initializer=init_ops.zeros_initializer,
dtype=dtype, trainable=False)
var = vs.get_variable(scope+"_var", shape=[feat_dim],
initializer=init_ops.ones_initializer,
dtype=dtype, trainable=False)
counter = vs.get_variable(scope+"_counter", shape=[],
initializer=init_ops.constant_initializer(0),
dtype=tf.int64, trainable=False)
zero_cnt = vs.get_variable(scope+"_zero_cnt", shape=[],
initializer=init_ops.constant_initializer(0),
dtype=tf.int64, trainable=False)
batch_mean, batch_var = moments(x, axes, name=scope+'_moments')
mean, var = cond(math_ops.equal(counter, zero_cnt), lambda: (batch_mean, batch_var),
lambda: (mean, var))
mean, var, counter = cond(deterministic, lambda: (mean, var, counter),
lambda: ((1-alpha) * batch_mean + alpha * mean,
(1-alpha) * batch_var + alpha * var,
counter + 1))
normed = batch_normalization(x, mean, var, beta, gamma, 1e-8)
return normed
class LSTMCell(RNNCell):
def __init__(self, num_units, use_peepholes=False,
cell_clip=None, initializer=None,
num_proj=None, num_unit_shards=1,
num_proj_shards=1, forget_bias=1.0,
bn=0, return_gate=False,
deterministic=None, activation=tanh):
"""
Initialize the parameters for an LSTM cell.
Args:
num_units: int, The number of units in the LSTM cell
use_peepholes: bool, set True to enable diagonal/peephole connections.
cell_clip: (optional) A float value, if provided the cell state is clipped
by this value prior to the cell output activation.
initializer: (optional) The initializer to use for the weight and
projection matrices.
num_proj: (optional) int, The output dimensionality for the projection
matrices. If None, no projection is performed.
num_unit_shards: How to split the weight matrix. If >1, the weight
matrix is stored across num_unit_shards.
num_proj_shards: How to split the projection matrix. If >1, the
projection matrix is stored across num_proj_shards.
forget_bias: Biases of the forget gate are initialized by default to 1
in order to reduce the scale of forgetting at the beginning of
the training.
return_gate: bool, set true to return the values of the gates.
bn: int, set 1,2 or 3 to enable sequence-wise batch normalization with
different level. Implemented according to arXiv:1603.09025
deterministic: Tensor, control training and testing phase, decide whether to
open batch normalization.
activation: Activation function of the inner states.
"""
self._num_units = num_units
self._use_peepholes = use_peepholes
self._cell_clip = cell_clip
self._initializer = initializer
self._num_proj = num_proj
self._num_unit_shards = num_unit_shards
self._num_proj_shards = num_proj_shards
self._forget_bias = forget_bias
self._activation = activation
self._bn = bn
self._return_gate = return_gate
self._deterministic = deterministic
self._return_gate = return_gate
if num_proj:
self._state_size = LSTMStateTuple(num_units, num_proj)
self._output_size = num_proj
else:
self._state_size = LSTMStateTuple(num_units, num_units)
self._output_size = num_units
@property
def state_size(self):
return self._state_size
@property
def output_size(self):
return self._output_size
def __call__(self, inputs, state, scope=None):
"""Run one step of LSTM.
Args:
inputs: input Tensor, 2D, batch x num_units.
state: if `state_is_tuple` is False, this must be a state Tensor,
`2-D, batch x state_size`. If `state_is_tuple` is True, this must be a
tuple of state Tensors, both `2-D`, with column sizes `c_state` and
`m_state`.
scope: VariableScope for the created subgraph; defaults to "LSTMCell".
Returns:
A tuple containing:
- A `2-D, [batch x output_dim]`, Tensor representing the output of the
LSTM after reading `inputs` when previous state was `state`.
Here output_dim is:
num_proj if num_proj was set,
num_units otherwise.
- Tensor(s) representing the new state of LSTM after reading `inputs` when
the previous state was `state`. Same type and shape(s) as `state`.
Raises:
ValueError: If input size cannot be inferred from inputs via
static shape inference.
"""
num_proj = self._num_units if self._num_proj is None else self._num_proj
(c_prev, m_prev) = state
dtype = inputs.dtype
input_size = inputs.get_shape().with_rank(2)[1]
if input_size.value is None:
raise ValueError("Could not infer input size from inputs.get_shape()[-1]")
scope_name = scope or type(self).__name__
with vs.variable_scope(scope_name,
initializer=self._initializer): # "LSTMCell"
if self._bn:
concat_w_i = _get_concat_variable(
"W_i", [input_size.value, 4 * self._num_units],
dtype, self._num_unit_shards)
concat_w_r = _get_concat_variable(
"W_r", [num_proj, 4 * self._num_units],
dtype, self._num_unit_shards)
b = vs.get_variable(
"B", shape=[4 * self._num_units],
initializer=array_ops.zeros_initializer, dtype=dtype)
else:
concat_w = _get_concat_variable(
"W", [input_size.value + num_proj, 4 * self._num_units],
dtype, self._num_unit_shards)
b = vs.get_variable(
"B", shape=[4 * self._num_units],
initializer=array_ops.zeros_initializer, dtype=dtype)
# i = input_gate, j = new_input, f = forget_gate, o = output_gate
if self._bn:
lstm_matrix_i = batch_norm(math_ops.matmul(inputs, concat_w_i), self._deterministic,
shift=False, scope=scope_name+'bn_i')
if self._bn > 1:
lstm_matrix_r = batch_norm(math_ops.matmul(m_prev, concat_w_r), self._deterministic,
shift=False, scope=scope_name+'bn_r')
else:
lstm_matrix_r = math_ops.matmul(m_prev, concat_w_r)
lstm_matrix = nn_ops.bias_add(math_ops.add(lstm_matrix_i, lstm_matrix_r), b)
else:
cell_inputs = array_ops.concat(1, [inputs, m_prev])
lstm_matrix = nn_ops.bias_add(math_ops.matmul(cell_inputs, concat_w), b)
i, j, f, o = array_ops.split(1, 4, lstm_matrix)
# Diagonal connections
if self._use_peepholes:
w_f_diag = vs.get_variable(
"W_F_diag", shape=[self._num_units], dtype=dtype)
w_i_diag = vs.get_variable(
"W_I_diag", shape=[self._num_units], dtype=dtype)
w_o_diag = vs.get_variable(
"W_O_diag", shape=[self._num_units], dtype=dtype)
if self._use_peepholes:
c = (sigmoid(f + self._forget_bias + w_f_diag * c_prev) * c_prev +
sigmoid(i + w_i_diag * c_prev) * self._activation(j))
else:
c = (sigmoid(f + self._forget_bias) * c_prev + sigmoid(i) *
self._activation(j))
if self._cell_clip is not None:
# pylint: disable=invalid-unary-operand-type
c = clip_ops.clip_by_value(c, -self._cell_clip, self._cell_clip)
# pylint: enable=invalid-unary-operand-type
if self._use_peepholes:
if self._bn > 2:
m = sigmoid(o + w_o_diag * c) * self._activation(batch_norm(c, self._deterministic,
scope=scope_name+'bn_m'))
else:
m = sigmoid(o + w_o_diag * c) * self._activation(c)
else:
if self._bn > 2:
m = sigmoid(o) * self._activation(batch_norm(c, self._deterministic,
scope=scope_name+'bn_m'))
else:
m = sigmoid(o) * self._activation(c)
if self._num_proj is not None:
concat_w_proj = _get_concat_variable(
"W_P", [self._num_units, self._num_proj],
dtype, self._num_proj_shards)
m = math_ops.matmul(m, concat_w_proj)
new_state = LSTMStateTuple(c, m)
if not self._return_gate:
return m, new_state
else:
return m, new_state, (i, j, f, o)