def get_slow_antecedent_scores(self, top_span_emb, top_antecedents,
top_antecedent_emb, top_antecedent_offsets,
top_span_speaker_ids, genre_emb):
k = util.shape(top_span_emb, 0)
c = util.shape(top_antecedents, 1)
feature_emb_list = []
if self.config["use_metadata"]:
top_antecedent_speaker_ids = tf.gather(top_span_speaker_ids,
top_antecedents) # [k, c]
same_speaker = tf.equal(tf.expand_dims(top_span_speaker_ids, 1),
top_antecedent_speaker_ids) # [k, c]
speaker_pair_emb = tf.gather(
tf.get_variable("same_speaker_emb",
[2, self.config["feature_size"]]),
tf.to_int32(same_speaker)) # [k, c, emb]
feature_emb_list.append(speaker_pair_emb)
tiled_genre_emb = tf.tile(
tf.expand_dims(tf.expand_dims(genre_emb, 0), 0),
[k, c, 1]) # [k, c, emb]
feature_emb_list.append(tiled_genre_emb)
if self.config["use_features"]:
antecedent_distance_buckets = self.bucket_distance(
top_antecedent_offsets) # [k, c]
antecedent_distance_emb = tf.gather(
tf.get_variable("antecedent_distance_emb",
[10, self.config["feature_size"]]),
antecedent_distance_buckets) # [k, c]
feature_emb_list.append(antecedent_distance_emb)
feature_emb = tf.concat(feature_emb_list, 2) # [k, c, emb]
feature_emb = tf.nn.dropout(feature_emb, self.dropout) # [k, c, emb]
target_emb = tf.expand_dims(top_span_emb, 1) # [k, 1, emb]
similarity_emb = top_antecedent_emb * target_emb # [k, c, emb]
target_emb = tf.tile(target_emb, [1, c, 1]) # [k, c, emb]
pair_emb = tf.concat(
[target_emb, top_antecedent_emb, similarity_emb, feature_emb],
2) # [k, c, emb]
with tf.variable_scope("slow_antecedent_scores"):
slow_antecedent_scores = util.ffnn(pair_emb,
self.config["ffnn_depth"],
self.config["ffnn_size"], 1,
self.dropout) # [k, c, 1]
slow_antecedent_scores = tf.squeeze(slow_antecedent_scores,
2) # [k, c]
return slow_antecedent_scores # [k, c]
def get_fast_antecedent_scores(self, top_span_emb):
with tf.variable_scope("src_projection"):
source_top_span_emb = tf.nn.dropout(
util.projection(top_span_emb, util.shape(top_span_emb, -1)),
self.dropout) # [k, emb]
target_top_span_emb = tf.nn.dropout(top_span_emb,
self.dropout) # [k, emb]
return tf.matmul(source_top_span_emb,
target_top_span_emb,
transpose_b=True) # [k, k]
def distance_pruning(self, top_span_emb, top_span_mention_scores, c):
k = util.shape(top_span_emb, 0)
top_antecedent_offsets = tf.tile(tf.expand_dims(tf.range(c) + 1, 0),
[k, 1]) # [k, c]
raw_top_antecedents = tf.expand_dims(
tf.range(k), 1) - top_antecedent_offsets # [k, c]
top_antecedents_mask = raw_top_antecedents >= 0 # [k, c]
top_antecedents = tf.maximum(raw_top_antecedents, 0) # [k, c]
top_fast_antecedent_scores = tf.expand_dims(
top_span_mention_scores, 1) + tf.gather(top_span_mention_scores,
top_antecedents) # [k, c]
top_fast_antecedent_scores += tf.log(
tf.to_float(top_antecedents_mask)) # [k, c]
return top_antecedents, top_antecedents_mask, top_fast_antecedent_scores, top_antecedent_offsets
def get_span_emb(self, head_emb, context_outputs, span_starts, span_ends):
span_emb_list = []
span_start_emb = tf.gather(context_outputs, span_starts) # [k, emb]
span_emb_list.append(span_start_emb)
span_end_emb = tf.gather(context_outputs, span_ends) # [k, emb]
span_emb_list.append(span_end_emb)
span_width = 1 + span_ends - span_starts # [k]
if self.config["use_features"]:
span_width_index = span_width - 1 # [k]
span_width_emb = tf.gather(
tf.get_variable("span_width_embeddings", [
self.config["max_span_width"], self.config["feature_size"]
]), span_width_index) # [k, emb]
span_width_emb = tf.nn.dropout(span_width_emb, self.dropout)
span_emb_list.append(span_width_emb)
if self.config["model_heads"]:
span_indices = tf.expand_dims(
tf.range(self.config["max_span_width"]), 0) + tf.expand_dims(
span_starts, 1) # [k, max_span_width]
span_indices = tf.minimum(
util.shape(context_outputs, 0) - 1,
span_indices) # [k, max_span_width]
span_text_emb = tf.gather(head_emb,
span_indices) # [k, max_span_width, emb]
with tf.variable_scope("head_scores"):
self.head_scores = util.projection(context_outputs,
1) # [num_words, 1]
span_head_scores = tf.gather(
self.head_scores, span_indices) # [k, max_span_width, 1]
span_mask = tf.expand_dims(
tf.sequence_mask(span_width,
self.config["max_span_width"],
dtype=tf.float32),
2) # [k, max_span_width, 1]
span_head_scores += tf.log(span_mask) # [k, max_span_width, 1]
span_attention = tf.nn.softmax(span_head_scores,
1) # [k, max_span_width, 1]
span_head_emb = tf.reduce_sum(span_attention * span_text_emb,
1) # [k, emb]
span_emb_list.append(span_head_emb)
span_emb = tf.concat(span_emb_list, 1) # [k, emb]
return span_emb # [k, emb]
def flatten_emb_by_sentence(self, emb, text_len_mask):
num_sentences = tf.shape(emb)[0]
max_sentence_length = tf.shape(emb)[1]
emb_rank = len(emb.get_shape())
if emb_rank == 2:
flattened_emb = tf.reshape(emb,
[num_sentences * max_sentence_length])
elif emb_rank == 3:
flattened_emb = tf.reshape(
emb, [num_sentences * max_sentence_length,
util.shape(emb, 2)])
else:
raise ValueError("Unsupported rank: {}".format(emb_rank))
return tf.boolean_mask(
flattened_emb,
tf.reshape(text_len_mask, [num_sentences * max_sentence_length]))
def lstm_contextualize(self, text_emb, text_len, text_len_mask):
num_sentences = tf.shape(text_emb)[0]
current_inputs = text_emb # [num_sentences, max_sentence_length, emb]
for layer in range(self.config["contextualization_layers"]):
with tf.variable_scope("layer_{}".format(layer)):
with tf.variable_scope("fw_cell"):
cell_fw = util.CustomLSTMCell(
self.config["contextualization_size"], num_sentences,
self.lstm_dropout)
with tf.variable_scope("bw_cell"):
cell_bw = util.CustomLSTMCell(
self.config["contextualization_size"], num_sentences,
self.lstm_dropout)
state_fw = tf.contrib.rnn.LSTMStateTuple(
tf.tile(cell_fw.initial_state.c, [num_sentences, 1]),
tf.tile(cell_fw.initial_state.h, [num_sentences, 1]))
state_bw = tf.contrib.rnn.LSTMStateTuple(
tf.tile(cell_bw.initial_state.c, [num_sentences, 1]),
tf.tile(cell_bw.initial_state.h, [num_sentences, 1]))
(fw_outputs, bw_outputs), _ = tf.nn.bidirectional_dynamic_rnn(
cell_fw=cell_fw,
cell_bw=cell_bw,
inputs=current_inputs,
sequence_length=text_len,
initial_state_fw=state_fw,
initial_state_bw=state_bw)
text_outputs = tf.concat(
[fw_outputs, bw_outputs],
2) # [num_sentences, max_sentence_length, emb]
text_outputs = tf.nn.dropout(text_outputs, self.lstm_dropout)
if layer > 0:
highway_gates = tf.sigmoid(
util.projection(text_outputs,
util.shape(text_outputs, 2))
) # [num_sentences, max_sentence_length, emb]
text_outputs = highway_gates * text_outputs + (
1 - highway_gates) * current_inputs
current_inputs = text_outputs
return self.flatten_emb_by_sentence(text_outputs, text_len_mask)
def coarse_to_fine_pruning(self, top_span_emb, top_span_mention_scores, c):
k = util.shape(top_span_emb, 0)
top_span_range = tf.range(k) # [k]
antecedent_offsets = tf.expand_dims(
top_span_range, 1) - tf.expand_dims(top_span_range, 0) # [k, k]
antecedents_mask = antecedent_offsets >= 1 # [k, k]
fast_antecedent_scores = tf.expand_dims(
top_span_mention_scores, 1) + tf.expand_dims(
top_span_mention_scores, 0) # [k, k]
fast_antecedent_scores += tf.log(
tf.to_float(antecedents_mask)) # [k, k]
fast_antecedent_scores += self.get_fast_antecedent_scores(
top_span_emb) # [k, k]
_, top_antecedents = tf.nn.top_k(fast_antecedent_scores,
c,
sorted=False) # [k, c]
top_antecedents_mask = util.batch_gather(antecedents_mask,
top_antecedents) # [k, c]
top_fast_antecedent_scores = util.batch_gather(
fast_antecedent_scores, top_antecedents) # [k, c]
top_antecedent_offsets = util.batch_gather(antecedent_offsets,
top_antecedents) # [k, c]
return top_antecedents, top_antecedents_mask, top_fast_antecedent_scores, top_antecedent_offsets
def get_predictions_and_loss(self, tokens, context_word_emb, head_word_emb,
lm_emb, char_index, text_len, speaker_ids,
genre, is_training, gold_starts, gold_ends,
cluster_ids, tokens_lm):
self.dropout = self.get_dropout(self.config["dropout_rate"],
is_training)
self.lexical_dropout = self.get_dropout(
self.config["lexical_dropout_rate"], is_training)
self.lstm_dropout = self.get_dropout(self.config["lstm_dropout_rate"],
is_training)
num_sentences = tf.shape(context_word_emb)[0]
max_sentence_length = tf.shape(context_word_emb)[1]
context_emb_list = [context_word_emb]
head_emb_list = [head_word_emb]
if self.config["char_embedding_size"] > 0:
char_emb = tf.gather(
tf.get_variable(
"char_embeddings",
[len(self.char_dict), self.config["char_embedding_size"]]),
char_index
) # [num_sentences, max_sentence_length, max_word_length, emb]
flattened_char_emb = tf.reshape(char_emb, [
num_sentences * max_sentence_length,
util.shape(char_emb, 2),
util.shape(char_emb, 3)
]) # [num_sentences * max_sentence_length, max_word_length, emb]
flattened_aggregated_char_emb = util.cnn(
flattened_char_emb, self.config["filter_widths"],
self.config["filter_size"]
) # [num_sentences * max_sentence_length, emb]
aggregated_char_emb = tf.reshape(flattened_aggregated_char_emb, [
num_sentences, max_sentence_length,
util.shape(flattened_aggregated_char_emb, 1)
]) # [num_sentences, max_sentence_length, emb]
context_emb_list.append(aggregated_char_emb)
head_emb_list.append(aggregated_char_emb)
if not self.lm_file:
# 采用Word2Vec
lm_emb = tf.convert_to_tensor(tokens_lm)
lm_emb_size = util.shape(lm_emb, 2)
lm_num_layers = util.shape(lm_emb, 3)
with tf.variable_scope("lm_aggregation"):
self.lm_weights = tf.nn.softmax(
tf.get_variable("lm_scores", [lm_num_layers],
initializer=tf.constant_initializer(0.0)))
self.lm_scaling = tf.get_variable(
"lm_scaling", [], initializer=tf.constant_initializer(1.0))
flattened_lm_emb = tf.reshape(
lm_emb,
[num_sentences * max_sentence_length * lm_emb_size, lm_num_layers])
flattened_aggregated_lm_emb = tf.matmul(
flattened_lm_emb, tf.expand_dims(
self.lm_weights,
1)) # [num_sentences * max_sentence_length * emb, 1]
aggregated_lm_emb = tf.reshape(
flattened_aggregated_lm_emb,
[num_sentences, max_sentence_length, lm_emb_size])
aggregated_lm_emb *= self.lm_scaling
context_emb_list.append(aggregated_lm_emb)
context_emb = tf.concat(context_emb_list,
2) # [num_sentences, max_sentence_length, emb]
head_emb = tf.concat(head_emb_list,
2) # [num_sentences, max_sentence_length, emb]
context_emb = tf.nn.dropout(
context_emb,
self.lexical_dropout) # [num_sentences, max_sentence_length, emb]
head_emb = tf.nn.dropout(
head_emb,
self.lexical_dropout) # [num_sentences, max_sentence_length, emb]
text_len_mask = tf.sequence_mask(
text_len,
maxlen=max_sentence_length) # [num_sentence, max_sentence_length]
context_outputs = self.lstm_contextualize(
context_emb, text_len, text_len_mask) # [num_words, emb]
num_words = util.shape(context_outputs, 0)
genre_emb = tf.gather(
tf.get_variable("genre_embeddings",
[len(self.genres), self.config["feature_size"]]),
genre) # [emb]
sentence_indices = tf.tile(
tf.expand_dims(tf.range(num_sentences), 1),
[1, max_sentence_length]) # [num_sentences, max_sentence_length]
flattened_sentence_indices = self.flatten_emb_by_sentence(
sentence_indices, text_len_mask) # [num_words]
flattened_head_emb = self.flatten_emb_by_sentence(
head_emb, text_len_mask) # [num_words]
candidate_starts = tf.tile(
tf.expand_dims(tf.range(num_words), 1),
[1, self.max_span_width]) # [num_words, max_span_width]
candidate_ends = candidate_starts + tf.expand_dims(
tf.range(self.max_span_width), 0) # [num_words, max_span_width]
candidate_start_sentence_indices = tf.gather(
flattened_sentence_indices,
candidate_starts) # [num_words, max_span_width]
candidate_end_sentence_indices = tf.gather(
flattened_sentence_indices,
tf.minimum(candidate_ends,
num_words - 1)) # [num_words, max_span_width]
candidate_mask = tf.logical_and(
candidate_ends < num_words,
tf.equal(
candidate_start_sentence_indices,
candidate_end_sentence_indices)) # [num_words, max_span_width]
flattened_candidate_mask = tf.reshape(
candidate_mask, [-1]) # [num_words * max_span_width]
candidate_starts = tf.boolean_mask(
tf.reshape(candidate_starts,
[-1]), flattened_candidate_mask) # [num_candidates]
candidate_ends = tf.boolean_mask(
tf.reshape(candidate_ends,
[-1]), flattened_candidate_mask) # [num_candidates]
candidate_sentence_indices = tf.boolean_mask(
tf.reshape(candidate_start_sentence_indices, [-1]),
flattened_candidate_mask) # [num_candidates]
candidate_cluster_ids = self.get_candidate_labels(
candidate_starts, candidate_ends, gold_starts, gold_ends,
cluster_ids) # [num_candidates]
candidate_span_emb = self.get_span_emb(
flattened_head_emb, context_outputs, candidate_starts,
candidate_ends) # [num_candidates, emb]
candidate_mention_scores = self.get_mention_scores(
candidate_span_emb) # [k, 1]
candidate_mention_scores = tf.squeeze(candidate_mention_scores,
1) # [k]
k = tf.to_int32(
tf.floor(
tf.to_float(tf.shape(context_outputs)[0]) *
self.config["top_span_ratio"]))
top_span_indices = coref_ops.extract_spans(
tf.expand_dims(candidate_mention_scores, 0),
tf.expand_dims(candidate_starts, 0),
tf.expand_dims(candidate_ends, 0), tf.expand_dims(k, 0),
util.shape(context_outputs, 0), True) # [1, k]
top_span_indices.set_shape([1, None])
top_span_indices = tf.squeeze(top_span_indices, 0) # [k]
top_span_starts = tf.gather(candidate_starts, top_span_indices) # [k]
top_span_ends = tf.gather(candidate_ends, top_span_indices) # [k]
top_span_emb = tf.gather(candidate_span_emb,
top_span_indices) # [k, emb]
top_span_cluster_ids = tf.gather(candidate_cluster_ids,
top_span_indices) # [k]
top_span_mention_scores = tf.gather(candidate_mention_scores,
top_span_indices) # [k]
top_span_sentence_indices = tf.gather(candidate_sentence_indices,
top_span_indices) # [k]
top_span_speaker_ids = tf.gather(speaker_ids, top_span_starts) # [k]
c = tf.minimum(self.config["max_top_antecedents"], k)
if self.config["coarse_to_fine"]:
top_antecedents, top_antecedents_mask, top_fast_antecedent_scores, top_antecedent_offsets = self.coarse_to_fine_pruning(
top_span_emb, top_span_mention_scores, c)
else:
top_antecedents, top_antecedents_mask, top_fast_antecedent_scores, top_antecedent_offsets = self.distance_pruning(
top_span_emb, top_span_mention_scores, c)
dummy_scores = tf.zeros([k, 1]) # [k, 1]
for i in range(self.config["coref_depth"]):
with tf.variable_scope("coref_layer", reuse=(i > 0)):
top_antecedent_emb = tf.gather(top_span_emb,
top_antecedents) # [k, c, emb]
top_antecedent_scores = top_fast_antecedent_scores + self.get_slow_antecedent_scores(
top_span_emb, top_antecedents, top_antecedent_emb,
top_antecedent_offsets, top_span_speaker_ids,
genre_emb) # [k, c]
top_antecedent_weights = tf.nn.softmax(
tf.concat([dummy_scores, top_antecedent_scores],
1)) # [k, c + 1]
top_antecedent_emb = tf.concat(
[tf.expand_dims(top_span_emb, 1), top_antecedent_emb],
1) # [k, c + 1, emb]
attended_span_emb = tf.reduce_sum(
tf.expand_dims(top_antecedent_weights, 2) *
top_antecedent_emb, 1) # [k, emb]
with tf.variable_scope("f"):
f = tf.sigmoid(
util.projection(
tf.concat([top_span_emb, attended_span_emb], 1),
util.shape(top_span_emb, -1))) # [k, emb]
top_span_emb = f * attended_span_emb + (
1 - f) * top_span_emb # [k, emb]
top_antecedent_scores = tf.concat(
[dummy_scores, top_antecedent_scores], 1) # [k, c + 1]
top_antecedent_cluster_ids = tf.gather(top_span_cluster_ids,
top_antecedents) # [k, c]
top_antecedent_cluster_ids += tf.to_int32(
tf.log(tf.to_float(top_antecedents_mask))) # [k, c]
same_cluster_indicator = tf.equal(top_antecedent_cluster_ids,
tf.expand_dims(
top_span_cluster_ids,
1)) # [k, c]
non_dummy_indicator = tf.expand_dims(top_span_cluster_ids > 0,
1) # [k, 1]
pairwise_labels = tf.logical_and(same_cluster_indicator,
non_dummy_indicator) # [k, c]
dummy_labels = tf.logical_not(
tf.reduce_any(pairwise_labels, 1, keepdims=True)) # [k, 1]
top_antecedent_labels = tf.concat([dummy_labels, pairwise_labels],
1) # [k, c + 1]
loss = self.softmax_loss(top_antecedent_scores,
top_antecedent_labels) # [k]
loss = tf.reduce_sum(loss) # []
return [
candidate_starts, candidate_ends, candidate_mention_scores,
top_span_starts, top_span_ends, top_antecedents,
top_antecedent_scores
], loss