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lstm_crf_explicit.py
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lstm_crf_explicit.py
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'''
Created on Mar 4, 2017
@author: Tuan
'''
'''
A work around for gathering (correspond to indexing on numpy array with another numpy array)
- Tensorflow couldn't run gradient for this
Issue: https://github.com/tensorflow/tensorflow/issues/206
Workaround: Turn the original params and indices to one dimension, then turn back to 2 dimensions
'''
import numpy as np
import tensorflow as tf
from utils import role_to_id, prep_to_id, event_to_id, DEVICE, TEST_DEVICE
try:
from tensorflow.nn.rnn_cell import BasicLSTMCell, DropoutWrapper, MultiRNNCell
except:
from tensorflow.contrib.rnn import BasicLSTMCell, DropoutWrapper, MultiRNNCell
def gather_2d(params, indices):
# only for two dim now
shape = params.get_shape().as_list()
assert len(shape) == 2, 'only support 2d matrix'
indices_shape = indices.get_shape().as_list()
assert indices_shape[1] == 2, 'only support indexing on both dimensions'
flat = tf.reshape(params, [shape[0] * shape[1]])
# flat_idx = tf.slice(indices, [0,0], [shape[0],1]) * shape[1] + tf.slice(indices, [0,1], [shape[0],1])
# flat_idx = tf.reshape(flat_idx, [flat_idx.get_shape().as_list()[0]])
flat_idx = indices[:,0] * shape[1] + indices[:,1]
return tf.gather(flat, flat_idx)
def gather_2d_to_shape(params, indices, output_shape):
flat = gather_2d(params, indices)
return tf.reshape(flat, output_shape)
# x -> (x, size)
def expand( tensor, size, axis = 1 ):
return tf.stack([tensor for _ in xrange(size)], axis = axis)
# x -> (size, x)
def expand_first( tensor, size ):
return tf.stack( [tensor for _ in xrange(size)] )
class LSTM_CRF_Exp(object):
'''
A model to recognize event recorded in 3d motions
This version is the explicit version that do the calculation explicitly on a specific graph
'''
def __init__(self, is_training, config):
self.config = config
self.batch_size = batch_size = config.batch_size
self.num_steps = num_steps = config.num_steps
self.n_input = n_input = config.n_input
self.label_classes = label_classes = config.label_classes
self.n_labels = len(self.label_classes)
size = config.hidden_size
self.crf_weight = crf_weight = config.crf_weight
'''
Start
|
|
|
Verb ------ Subject ------- Theme --------- Object
|
|
|
Preposition
'''
no_of_theme = no_of_subject = no_of_object = len(role_to_id)
no_of_prep = len(prep_to_id)
no_of_event = len(event_to_id)
with tf.variable_scope("crf"):
'''Start -- Theme '''
self.A_start_t = A_start_t = tf.get_variable("A_start_t", [no_of_theme])
'''Theme -- Object '''
self.A_to = A_to = tf.get_variable("A_to", [no_of_theme, no_of_object])
'''Theme -- Subject '''
self.A_ts = A_ts = tf.get_variable("A_ts", [no_of_theme, no_of_subject])
'''Theme -- Preposition '''
self.A_tp = A_tp = tf.get_variable("A_tp", [no_of_theme, no_of_prep])
'''Subject -- Verb '''
self.A_se = A_se = tf.get_variable("A_se", [no_of_subject, no_of_event])
# Input data and labels should be set as placeholders
self._input_data = tf.placeholder(tf.float32, [batch_size, num_steps, n_input])
self._targets = tf.placeholder(tf.int32, [batch_size, self.n_labels])
# self.n_labels cells for self.n_labels outputs
lstm_cells = [BasicLSTMCell(size, forget_bias = 0.0, state_is_tuple=True)\
for _ in xrange(self.n_labels)]
# DropoutWrapper is a decorator that adds Dropout functionality
if is_training and config.keep_prob < 1:
lstm_cells = [DropoutWrapper(lstm_cell, output_keep_prob=config.keep_prob)\
for lstm_cell in lstm_cells]
cells = [MultiRNNCell([lstm_cell] * config.num_layers, state_is_tuple=True)\
for lstm_cell in lstm_cells]
# Initial states of the cells
# cell.state_size = config.num_layers * 2 * size
# Size = self.n_labels x ( batch_size x cell.state_size )
self._initial_state = [cell.zero_state(batch_size, tf.float32) for cell in cells]
# Transformation of input to a list of num_steps data points
inputs = tf.transpose(self._input_data, [1, 0, 2]) #(num_steps, batch_size, n_input)
inputs = tf.reshape(inputs, [-1, n_input]) # (num_steps * batch_size, n_input)
with tf.variable_scope("hidden"):
weight = tf.get_variable("weight", [n_input, size])
bias = tf.get_variable("bias", [size])
inputs = tf.matmul(inputs, weight) + bias
# inputs = tf.reshape(inputs, (-1, num_steps, size)) # (batch_size, num_steps, size)
# For tf.nn.rnn
inputs = tf.split(inputs, num_steps, axis = 0) # num_steps * ( batch_size, size )
outputs_and_states = []
# A list of n_labels values
# Each value is (output, state)
# output is of size: num_steps * ( batch_size, size )
# state is of size: ( batch_size, cell.state_size )
for i in xrange(self.n_labels):
with tf.variable_scope("lstm" + str(i)):
# output_and_state = tf.nn.rnn(cells[i], inputs, initial_state = self._initial_state[i])
output_and_state = tf.contrib.rnn.static_rnn (cells[i], inputs, initial_state = self._initial_state[i])
# output_and_state = tf.nn.dynamic_rnn(cells[i], inputs, dtype=tf.float32, initial_state = self._initial_state[i])
outputs_and_states.append(output_and_state)
# n_labels x ( batch_size, size )
outputs = [output_and_state[0][-1]\
for output_and_state in outputs_and_states]
# n_labels x ( num_steps, batch_size, size )
# outputs = [tf.transpose(output_and_state[0], [1, 0, 2])
# for output_and_state in outputs_and_states]
# Last step
# n_labels x ( batch_size, size )
#outputs = [tf.gather(output, int(output.get_shape()[0]) - 1)
# for output in outputs]
# n_labels x ( batch_size, cell.state_size )
self._final_state = [output_and_state[1]\
for output_and_state in outputs_and_states]
# self.n_labels x ( batch_size, n_classes )
self.logits = logits = []
for i in xrange(self.n_labels):
label_class = label_classes[i]
n_classes = len(label_class)
with tf.variable_scope("output" + str(i)):
weight = tf.get_variable("weight", [size, n_classes])
bias = tf.get_variable("bias", [n_classes])
# ( batch_size, n_classes )
logit = tf.matmul(outputs[i], weight) + bias
# logits
logits.append(logit)
self._debug = []
'''----------------------------------------------------------------------------'''
'''Message passing algorithm to sum over exponentinal terms of all combinations'''
'''----------------------------------------------------------------------------'''
logit_s = logits[0]
logit_o = logits[1]
logit_t = logits[2]
logit_e = logits[3]
logit_p = logits[4]
# Calculate log values for Node Theme and Subject
# Which is 2 inner nodes (we don't need to store log values for leaf nodes)
# Message passing between Start and Theme; Theme and Object ; Theme and Preposition
'''
theme_values will store sums of values that has been passed through Start, Object, Preposition
Start
|
|
|
v
Verb ------ Subject ------- Theme <--------- Object
^
|
|
|
Preposition
Verb ------ Subject ------- Theme*
'''
'''Start -- Theme '''
# (batch_size, #Theme)
log_start_t = logit_t + crf_weight * A_start_t
'''Theme -- Object '''
# (batch_size, #Theme)
log_t_o = tf.reduce_min( crf_weight * tf.transpose(A_to) + expand(logit_o, no_of_theme, axis = 2), 1)
log_t_o += tf.log(tf.reduce_sum( tf.exp(crf_weight * tf.transpose(A_to) +\
expand(logit_o, no_of_theme, axis = 2) -\
expand(log_t_o, no_of_object, axis = 1) ), 1))
'''Theme -- Preposition'''
log_t_p = tf.reduce_min(crf_weight * tf.transpose(A_tp) + expand(logit_p, no_of_theme, axis = 2), 1)
log_t_p += tf.log(tf.reduce_sum( tf.exp(crf_weight * tf.transpose(A_tp) +\
expand(logit_p, no_of_theme, axis = 2) -\
expand(log_t_p, no_of_prep, axis = 1) ), 1))
# (batch_size, #Theme)
theme_values = log_start_t + log_t_o + log_t_p
'''
subject_values will store sums of values that has been passed on edges (Subject, Theme*) and (Subject, Verb)
Verb ------> Subject <------- Theme*
Subject *
'''
# (batch_size, #Subject)
log_s_t = tf.reduce_min(crf_weight * A_ts + expand(theme_values, no_of_subject, axis = 2), 1)
log_s_t += tf.log(tf.reduce_sum(tf.exp(crf_weight * A_ts +\
expand(theme_values, no_of_subject, axis = 2) -\
expand(log_s_t, no_of_theme, axis = 1) ), 1))
# (batch_size, #Subject)
log_s_e = tf.reduce_min(crf_weight * tf.transpose(A_se) + expand(logit_e, no_of_subject, axis = 2), 1)
log_s_e += tf.log(tf.reduce_sum(tf.exp(crf_weight * tf.transpose(A_se) +\
expand(logit_e, no_of_subject, axis = 2) -\
expand(log_s_e, no_of_event, axis = 1) ), 1))
subject_values = tf.transpose(logit_s + log_s_t + log_s_e)
# Sum over all possible values of subject
# batch_size
log_sum = tf.reduce_min(subject_values, 0)
log_sum += tf.log(tf.reduce_sum(tf.exp(subject_values - log_sum), 0))
# This could be improve when multidimensional array indexing is supported
# Known issue
# https://github.com/tensorflow/tensorflow/issues/206
# Currently formularizing is ok, but gpu couldn't learn gradient
# batch_size
correct_s = self._targets[:,0]
correct_o = self._targets[:,1]
correct_t = self._targets[:,2]
correct_e = self._targets[:,3]
correct_p = self._targets[:,4]
logit_correct = \
crf_weight * tf.gather(A_start_t, correct_t) +\
crf_weight * gather_2d(A_to, tf.transpose(tf.stack([correct_t, correct_o]))) +\
crf_weight * gather_2d(A_tp, tf.transpose(tf.stack([correct_t, correct_p]))) +\
crf_weight * gather_2d(A_ts, tf.transpose(tf.stack([correct_t, correct_s]))) +\
crf_weight * gather_2d(A_se, tf.transpose(tf.stack([correct_s, correct_e]))) +\
gather_2d(logit_t, tf.transpose(tf.stack([tf.range(batch_size), correct_t]))) +\
gather_2d(logit_o, tf.transpose(tf.stack([tf.range(batch_size), correct_o]))) +\
gather_2d(logit_p, tf.transpose(tf.stack([tf.range(batch_size), correct_p]))) +\
gather_2d(logit_e, tf.transpose(tf.stack([tf.range(batch_size), correct_e]))) +\
gather_2d(logit_s, tf.transpose(tf.stack([tf.range(batch_size), correct_s])))
self._cost = tf.reduce_mean(log_sum - logit_correct)
if is_training:
self.make_train_op()
else:
self.make_test_op()
# self._test_op = ( logits, A_start_t, A_to, A_ts, A_tp, A_se )
self._saver = tf.train.Saver()
def make_train_op(self):
self._lr = tf.Variable(0.0, trainable=False)
tvars = tf.trainable_variables()
self._train_op = []
grads, _ = tf.clip_by_global_norm(tf.gradients(self._cost, tvars),
self.config.max_grad_norm)
optimizer = tf.train.GradientDescentOptimizer(self.lr)
self._train_op = optimizer.apply_gradients(zip(grads, tvars))
def make_test_op(self):
no_of_theme = no_of_subject = no_of_object = len(role_to_id)
no_of_prep = len(prep_to_id)
no_of_event = len(event_to_id)
logit_s = self.logits[0]
logit_o = self.logits[1]
logit_t = self.logits[2]
logit_e = self.logits[3]
logit_p = self.logits[4]
'''---------------------------------------------------------------'''
'''Message passing algorithm to max over terms of all combinations'''
'''---------------------------------------------------------------'''
# For theme
# In collapsing, two nodes are collapsed into Theme : Object and Preposition
best_combination_theme = dict( (slot, tf.zeros((self.batch_size, no_of_theme), dtype=np.int32)) for slot in ['Object', 'Preposition'] )
# For subject
# In collapsing, two nodes are collapsed into Subject : Theme and Event
best_combination_subject = dict ( (slot, tf.zeros((self.batch_size, no_of_subject), dtype=np.int32)) for slot in ['Theme', 'Event'])
# (batch_size, #Theme)
best_theme_values = logit_t + self.crf_weight * self.A_start_t
# (#Object, batch_size, #Theme)
o_values = [expand(logit_o[:, o], no_of_theme) + self.crf_weight * self.A_to[:,o] for o in xrange(no_of_object)]
best_theme_values += tf.reduce_max(o_values, 0)
# Best value on edge ( Theme -> Object )
best_combination_theme['Object'] = tf.cast(tf.argmax(o_values, 0), np.int32)
# (#Prep, batch_size, #Theme)
p_values = [expand(logit_p[:, p],no_of_theme) + self.crf_weight * self.A_tp[:,p] for p in xrange(no_of_prep)]
best_theme_values += tf.reduce_max(p_values, 0)
# Best value on edge ( Theme -> Preposition )
best_combination_theme['Preposition'] = tf.cast(tf.argmax(p_values, 0), np.int32)
# (batch_size, #Subject)
best_subject_values = logit_s
# Message passing between Theme and Subject
# (#Theme, batch_size, #Subject)
t_values = [expand(best_theme_values[:, t], no_of_subject) + self.crf_weight * self.A_ts[t,:] for t in xrange(no_of_theme)]
best_subject_values += tf.reduce_max(t_values, 0)
# Best value on edge ( Subject -> Theme )
# (batch_size, #Subject)
best_combination_subject['Theme'] = tf.cast(tf.argmax(t_values, 0), np.int32)
# Message passing between Subject and Verb
# (#Event, batch_size, #Subject)
e_values = [expand(logit_e[:, e], no_of_subject) + self.crf_weight * self.A_se[:,e] for e in xrange(no_of_event)]
# (batch_size, #Subject)
best_subject_values += tf.reduce_max(e_values, 0)
# Best value on edge ( Subject -> Event )
best_combination_subject['Event'] = tf.cast(tf.argmax(e_values, 0), np.int32)
"""
======================================================
Propagate the best combination through message passing
======================================================
"""
best_combination = [tf.zeros((self.batch_size, no_of_subject), dtype=np.int32) for _ in xrange(self.n_labels)]
best_combination[0] = expand_first(range(no_of_subject), self.batch_size)
best_combination[2] = best_combination_subject['Theme']
best_combination[3] = best_combination_subject['Event']
"""
Propagate from Theme to [Object, Preposition]
"""
# (batch_size, #Subject)
q = np.array([[i for _ in xrange(no_of_subject)] for i in xrange(self.batch_size)])
# (batch_size x #Subject, 2)
indices = tf.reshape( tf.transpose( tf.stack ( [q, best_combination_subject['Theme']]), [1, 2, 0] ), [-1, 2])
for index, slot in [(1, 'Object'), (4, 'Preposition')]:
best_combination[index] = gather_2d_to_shape(best_combination_theme[slot],
indices, (self.batch_size, no_of_subject))
# Take the best out of all subject values
# batch_size
best_best_subject_values = tf.argmax(best_subject_values, 1)
# (batch_size, 2)
# Indices on best_combination[index] should have order of (self.batch_size, #Subject)
indices = tf.transpose( tf.stack([range(self.batch_size), best_best_subject_values]))
# (batch_size, self.n_labels)
out = tf.transpose(tf.stack([gather_2d( best_combination[t], indices ) for t in xrange(self.n_labels)]))
# (self.n_labels, batch_size)
correct_preds = [tf.equal(out[:,i], self._targets[:,i]) \
for i in xrange(self.n_labels)]
# Return number of correct predictions as well as predictions
self._test_op = ([out[:,i] for i in xrange(self.n_labels)],
[tf.reduce_mean(tf.cast(correct_pred, np.float32)) \
for correct_pred in correct_preds])
def assign_lr(self, session, lr_value):
session.run(tf.assign(self.lr, lr_value))
@property
def debug(self):
return self._debug
@property
def saver(self):
return self._saver
@property
def input_data(self):
return self._input_data
@property
def targets(self):
return self._targets
@property
def initial_state(self):
return self._initial_state
@property
def cost(self):
return self._cost
@property
def final_state(self):
return self._final_state
@property
def lr(self):
return self._lr
@property
def train_op(self):
return self._train_op
@property
def test_op(self):
return self._test_op