def get_masked_lm_output(config,
input_tensor,
output_weights,
positions,
label_ids,
label_weights,
reuse=None):
"""Get loss and log probs for the masked LM."""
input_tensor = tf.cast(input_tensor, tf.float32)
positions = tf.cast(positions, tf.int32)
label_ids = tf.cast(label_ids, tf.int32)
label_weights = tf.cast(label_weights, tf.float32)
input_tensor = bert_utils.gather_indexes(input_tensor, positions)
"""
flatten masked lm ids with positions
"""
with tf.variable_scope("cls/predictions", reuse=reuse):
# We apply one more non-linear transformation before the output layer.
# This matrix is not used after pre-training.
with tf.variable_scope("transform"):
input_tensor = tf.layers.dense(
input_tensor,
units=config.hidden_size,
activation=bert_modules.get_activation(config.hidden_act),
kernel_initializer=bert_modules.create_initializer(
config.initializer_range))
input_tensor = bert_modules.layer_norm(input_tensor)
# The output weights are the same as the input embeddings, but there is
# an output-only bias for each token.
output_bias = tf.get_variable("output_bias",
shape=[config.vocab_size],
initializer=tf.zeros_initializer())
logits = tf.matmul(input_tensor, output_weights, transpose_b=True)
logits = tf.nn.bias_add(logits, output_bias)
log_probs = tf.nn.log_softmax(logits, axis=-1)
label_ids = tf.reshape(label_ids, [-1])
label_weights = tf.reshape(label_weights, [-1])
# one_hot_labels = tf.one_hot(
# label_ids, depth=config.vocab_size, dtype=tf.float32)
per_example_loss = tf.nn.sparse_softmax_cross_entropy_with_logits(
labels=label_ids, logits=logits)
numerator = tf.reduce_sum(label_weights * per_example_loss)
denominator = tf.reduce_sum(label_weights) + 1e-5
# The `positions` tensor might be zero-padded (if the sequence is too
# short to have the maximum number of predictions). The `label_weights`
# tensor has a value of 1.0 for every real prediction and 0.0 for the
# padding predictions.
# per_example_loss = -tf.reduce_sum(log_probs * one_hot_labels, axis=[-1])
# numerator = tf.reduce_sum(label_weights * per_example_loss)
# denominator = tf.reduce_sum(label_weights) + 1e-5
loss = numerator / denominator
return (loss, per_example_loss, log_probs)
def build_output_logits(self, **kargs):
layer_num = kargs.get("layer_num", -1)
self.sequence_output = self.get_encoder_layers(layer_num)
input_shape_list = bert_utils.get_shape_list(self.sequence_output,
expected_rank=3)
batch_size = input_shape_list[0]
seq_length = input_shape_list[1]
hidden_dims = input_shape_list[2]
embedding_projection = kargs.get('embedding_projection', None)
scope = kargs.get('scope', None)
if scope:
scope = scope + '/' + 'cls/predictions'
else:
scope = 'cls/predictions'
tf.logging.info("**** mlm generator scope **** %s", str(scope))
# with tf.variable_scope("cls/predictions", reuse=tf.AUTO_REUSE):
with tf.variable_scope(scope, reuse=tf.AUTO_REUSE):
if self.config.get('ln_type', 'postln') == 'preln':
input_tensor = bert_modules.layer_norm(self.sequence_output)
tf.logging.info("**** pre ln doing layer norm ****")
elif self.config.get('ln_type', 'postln') == 'postln':
input_tensor = self.sequence_output
tf.logging.info("**** post ln ****")
else:
input_tensor = self.sequence_output
tf.logging.info("**** post ln ****")
# if config.get("embedding", "factorized") == "factorized":
# projection_width = config.hidden_size
# else:
# projection_width = config.embedding_size
if self.config.get("embedding",
"none_factorized") == "none_factorized":
projection_width = self.config.hidden_size
tf.logging.info("==not using embedding factorized==")
else:
projection_width = self.config.get('embedding_size',
self.config.hidden_size)
tf.logging.info(
"==using embedding factorized: embedding size: %s==",
str(projection_width))
with tf.variable_scope("transform"):
input_tensor = tf.layers.dense(
input_tensor,
units=projection_width,
activation=bert_modules.get_activation(
self.config.hidden_act),
kernel_initializer=bert_modules.create_initializer(
self.config.initializer_range))
if self.config.get('ln_type', 'postln') == 'preln':
input_tensor = input_tensor
tf.logging.info("**** pre ln ****")
elif self.config.get('ln_type', 'postln') == 'postln':
input_tensor = bert_modules.layer_norm(input_tensor)
tf.logging.info("**** post ln doing layer norm ****")
else:
input_tensor = bert_modules.layer_norm(input_tensor)
tf.logging.info("**** post ln doing layer norm ****")
if embedding_projection is not None:
# batch x seq x hidden, embedding x hidden
print(input_tensor.get_shape(),
embedding_projection.get_shape())
input_tensor = tf.einsum("abc,dc->abd", input_tensor,
embedding_projection)
else:
print("==no need for embedding projection==")
input_tensor = input_tensor
output_bias = tf.get_variable("output_bias",
shape=[self.config.vocab_size],
initializer=tf.zeros_initializer())
# batch x seq x embedding
logits = tf.einsum("abc,dc->abd", input_tensor,
self.embedding_table)
self.logits = tf.nn.bias_add(logits, output_bias)
def multi_position_classifier(config, features, sequence_output, num_labels,
dropout_prob):
final_hidden_shape = bert_utils.get_shape_list(sequence_output,
expected_rank=3)
print(final_hidden_shape, "====multi-choice shape====")
answer_pos = tf.cast(features['label_positions'], tf.int32)
cls_pos = tf.zeros_like(answer_pos)
input_tensor = bert_utils.gather_indexes(sequence_output, answer_pos)
cls_tensor = bert_utils.gather_indexes(sequence_output, cls_pos)
answer_cls_tensor = tf.concat([cls_tensor, input_tensor], axis=-1)
input_tensor = tf.layers.dense(
answer_cls_tensor,
units=config.hidden_size,
activation=bert_modules.get_activation(config.hidden_act),
kernel_initializer=bert_modules.create_initializer(
config.initializer_range))
input_tensor = bert_modules.layer_norm(input_tensor)
output_weights = tf.get_variable(
"output_weights", [num_labels, final_hidden_shape[-1]],
initializer=tf.truncated_normal_initializer(stddev=0.02))
output_bias = tf.get_variable("output_bias",
shape=[num_labels],
initializer=tf.zeros_initializer())
logits = tf.matmul(input_tensor, output_weights, transpose_b=True)
logits = tf.nn.bias_add(logits, output_bias)
label_ids = tf.reshape(tf.cast(features['label_ids'], tf.int32), [-1])
label_weights = tf.reshape(tf.cast(features['label_weights'], tf.float32),
[-1])
if config.get('class_weights', None):
class_weights = tf.constant(
np.array(config.class_weights).astype(np.float32))
if config.get("loss", "entropy") == "focal_loss":
per_example_loss, _ = loss_utils.focal_loss_multi_v1(
config, logits=logits, labels=tf.stop_gradient(label_ids))
elif config.get("loss", "smoothed_ce") == 'smoothed_ce':
per_example_loss = loss_utils.ce_label_smoothing(
config, logits=logits, labels=tf.stop_gradient(label_ids))
elif config.get('loss', 'class_balanced_focal') == 'class_balanced_focal':
per_example_loss, _ = loss_utils.class_balanced_focal_loss_multi_v1(
config,
logits=logits,
labels=label_ids,
label_weights=class_weights)
else:
per_example_loss = tf.nn.sparse_softmax_cross_entropy_with_logits(
labels=tf.stop_gradient(label_ids), logits=logits)
numerator = tf.reduce_sum(label_weights * per_example_loss)
denominator = tf.reduce_sum(label_weights) + 1e-5
loss = numerator / denominator
return (loss, per_example_loss, logits)
def get_masked_lm_output(config, input_tensor, output_weights, positions,
label_ids, label_weights, **kargs):
"""Get loss and log probs for the masked LM."""
reuse = kargs.get('reuse', False)
input_tensor = tf.cast(input_tensor, tf.float32)
positions = tf.cast(positions, tf.int32)
label_ids = tf.cast(label_ids, tf.int32)
label_weights = tf.cast(label_weights, tf.float32)
scope = kargs.get('scope', None)
if scope:
scope = scope + '/' + 'cls/predictions'
else:
scope = 'cls/predictions'
tf.logging.info("**** mlm scope **** %s", str(scope))
# if config.get("embedding", "factorized") == "factorized":
# projection_width = config.hidden_size
# else:
# projection_width = config.embedding_size
if config.get("embedding", "none_factorized") == "none_factorized":
projection_width = config.hidden_size
tf.logging.info("==not using embedding factorized==")
else:
projection_width = config.get('embedding_size', config.hidden_size)
tf.logging.info("==using embedding factorized: embedding size: %s==", str(projection_width))
input_tensor = bert_utils.gather_indexes(input_tensor, positions)
"""
flatten masked lm ids with positions
"""
# with tf.variable_scope("cls/predictions", reuse=reuse):
with tf.variable_scope(scope, reuse=reuse):
# We apply one more non-linear transformation before the output layer.
# This matrix is not used after pre-training.
with tf.variable_scope("transform"):
input_tensor = tf.layers.dense(
input_tensor,
units=projection_width,
activation=bert_modules.get_activation(config.hidden_act),
kernel_initializer=bert_modules.create_initializer(
config.initializer_range))
input_tensor = bert_modules.layer_norm(input_tensor)
# The output weights are the same as the input embeddings, but there is
# an output-only bias for each token.
output_bias = tf.get_variable(
"output_bias",
shape=[config.vocab_size],
initializer=tf.zeros_initializer())
logits = tf.matmul(input_tensor, output_weights, transpose_b=True)
logits = tf.nn.bias_add(logits, output_bias)
log_probs = tf.nn.log_softmax(logits, axis=-1)
label_ids = tf.reshape(label_ids, [-1])
label_weights = tf.reshape(label_weights, [-1])
one_hot_labels = tf.one_hot(
label_ids, depth=config.vocab_size, dtype=tf.float32)
per_example_loss = tf.nn.sparse_softmax_cross_entropy_with_logits(
labels=tf.stop_gradient(label_ids),
logits=logits)
# per_example_loss = -tf.reduce_sum(log_probs * one_hot_labels, axis=[-1])
numerator = tf.reduce_sum(label_weights * per_example_loss)
denominator = tf.reduce_sum(label_weights) + 1e-5
# The `positions` tensor might be zero-padded (if the sequence is too
# short to have the maximum number of predictions). The `label_weights`
# tensor has a value of 1.0 for every real prediction and 0.0 for the
# padding predictions.
# per_example_loss = -tf.reduce_sum(log_probs * one_hot_labels, axis=[-1])
# numerator = tf.reduce_sum(label_weights * per_example_loss)
# denominator = tf.reduce_sum(label_weights) + 1e-5
loss = numerator / denominator
return (loss, per_example_loss, log_probs, label_weights)
def seq_mask_masked_lm_output(config, input_tensor, output_weights,
input_mask, input_ori_ids, input_ids,
sampled_binary_mask, **kargs):
input_shape_list = bert_utils.get_shape_list(input_tensor, expected_rank=3)
batch_size = input_shape_list[0]
seq_length = input_shape_list[1]
hidden_dims = input_shape_list[2]
embedding_projection = kargs.get('embedding_projection', None)
scope = kargs.get('scope', None)
if scope:
scope = scope + '/' + 'cls/predictions'
else:
scope = 'cls/predictions'
tf.logging.info("**** mlm generator scope **** %s", str(scope))
# with tf.variable_scope("cls/predictions", reuse=tf.AUTO_REUSE):
with tf.variable_scope(scope, reuse=tf.AUTO_REUSE):
if config.get('ln_type', 'postln') == 'preln':
input_tensor = bert_modules.layer_norm(input_tensor)
elif config.get('ln_type', 'postln') == 'postln':
input_tensor = input_tensor
else:
input_tensor = input_tensor
# if config.get("embedding", "factorized") == "factorized":
# projection_width = config.hidden_size
# else:
# projection_width = config.embedding_size
if config.get("embedding", "none_factorized") == "none_factorized":
projection_width = config.hidden_size
tf.logging.info("==not using embedding factorized==")
else:
projection_width = config.get('embedding_size', config.hidden_size)
tf.logging.info("==using embedding factorized: embedding size: %s==", str(projection_width))
with tf.variable_scope("transform"):
input_tensor = tf.layers.dense(
input_tensor,
units=projection_width,
activation=bert_modules.get_activation(config.hidden_act),
kernel_initializer=bert_modules.create_initializer(
config.initializer_range))
if config.get('ln_type', 'postln') == 'preln':
input_tensor = input_tensor
elif config.get('ln_type', 'postln') == 'postln':
input_tensor = bert_modules.layer_norm(input_tensor)
else:
input_tensor = bert_modules.layer_norm(input_tensor)
if embedding_projection is not None:
# batch x seq x hidden, embedding x hidden
print(input_tensor.get_shape(), embedding_projection.get_shape())
input_tensor = tf.einsum("abc,dc->abd", input_tensor, embedding_projection)
else:
print("==no need for embedding projection==")
input_tensor = input_tensor
output_bias = tf.get_variable(
"output_bias",
shape=[config.vocab_size],
initializer=tf.zeros_initializer())
# batch x seq x embedding
logits = tf.einsum("abc,dc->abd", input_tensor, output_weights)
logits = tf.nn.bias_add(logits, output_bias)
"""
if input_ori_ids[i] is random pertubated, sampled_binary_mask[i]=1
"""
sampled_binary_mask = tf.cast(sampled_binary_mask, tf.float32)
input_mask = tf.cast(input_mask, tf.float32)
sampled_binary_mask *= input_mask
per_example_loss = tf.nn.sparse_softmax_cross_entropy_with_logits(
logits=logits,
labels=tf.stop_gradient(input_ori_ids),
)
per_example_loss *= sampled_binary_mask
loss = tf.reduce_sum(per_example_loss) / (1e-10 + tf.reduce_sum(sampled_binary_mask))
return (loss, per_example_loss, logits, sampled_binary_mask)
def emb_score(config, input_tensor, input_ids,
output_weights,
input_mask, **kargs):
input_shape_list = bert_utils.get_shape_list(input_tensor, expected_rank=3)
batch_size = input_shape_list[0]
seq_length = input_shape_list[1]
hidden_dims = input_shape_list[2]
scope = kargs.get('scope', None)
if scope:
lm_scope = scope + '/' + 'cls/predictions'
else:
lm_scope = 'cls/predictions'
tf.logging.info("**** mlm generator scope **** %s", str(lm_scope))
# with tf.variable_scope("cls/predictions", reuse=tf.AUTO_REUSE):
with tf.variable_scope(lm_scope, reuse=tf.AUTO_REUSE):
if config.get('ln_type', 'postln') == 'preln':
input_tensor = bert_modules.layer_norm(input_tensor)
elif config.get('ln_type', 'postln') == 'postln':
input_tensor = input_tensor
else:
input_tensor = input_tensor
if config.get("embedding", "none_factorized") == "none_factorized":
projection_width = config.hidden_size
tf.logging.info("==not using embedding factorized==")
else:
projection_width = config.get('embedding_size', config.hidden_size)
tf.logging.info("==using embedding factorized: embedding size: %s==", str(projection_width))
if kargs.get("energy_pooling", "mi") == "mi":
with tf.variable_scope("transform"):
input_tensor = tf.layers.dense(
input_tensor,
units=projection_width,
activation=bert_modules.get_activation(config.hidden_act),
kernel_initializer=bert_modules.create_initializer(
config.initializer_range))
if config.get('ln_type', 'postln') == 'preln':
input_tensor = input_tensor
elif config.get('ln_type', 'postln') == 'postln':
input_tensor = bert_modules.layer_norm(input_tensor)
else:
input_tensor = bert_modules.layer_norm(input_tensor)
output_bias = tf.get_variable(
"output_bias",
shape=[config.vocab_size],
initializer=tf.zeros_initializer())
tf.logging.info("****** mi using mlm transform *******")
elif kargs.get("energy_pooling", "mi") == "cls":
with tf.variable_scope("transform_ebm"):
# We "pool" the model by simply taking the hidden state corresponding
# to the first token. We assume that this has been pre-trained
first_token_tensor = tf.squeeze(input_tensor[:, 0:1, :], axis=1)
input_tensor = tf.layers.dense(
first_token_tensor,
config.hidden_size,
activation=tf.tanh, #bert_modules.get_activation(config.hidden_act),
kernel_initializer=bert_modules.create_initializer(config.initializer_range))
tf.logging.info("****** using cls pooling *******")
else:
with tf.variable_scope("transform_ebm"):
input_tensor = tf.layers.dense(
input_tensor,
units=projection_width,
activation=tf.tanh, #bert_modules.get_activation(config.hidden_act),
kernel_initializer=bert_modules.create_initializer(
config.initializer_range))
tf.logging.info("****** using other pooling transform *******")
# with tf.variable_scope("cls/predictions", reuse=tf.AUTO_REUSE):
if scope:
ebm_scope = scope + '/' + 'ebm/predictions'
else:
ebm_scope = 'ebm/predictions'
tf.logging.info("**** ebm generator scope **** %s", str(ebm_scope))
print(input_tensor.get_shape(), "==input_tensor shape==")
with tf.variable_scope(ebm_scope, reuse=tf.AUTO_REUSE):
# assume the whole model is self-normalization
if kargs.get("normalized_constant", "constant") == 'zero_constant':
normalized_constant = tf.get_variable(
"ebm_normalized_constant",
shape=[config.max_position_embeddings],
initializer=tf.zeros_initializer())
valid_seq_length = tf.cast(tf.reduce_sum(input_mask, axis=-1), tf.int32) # batch_size
onehot_length_ids = tf.one_hot(valid_seq_length, config.max_position_embeddings)
input_normalized_constant = tf.einsum("ab,b->a", tf.cast(onehot_length_ids, tf.float32), normalized_constant)
tf.logging.info("****** zero_constant logz *******")
elif kargs.get("normalized_constant", "constant") == 'one_constant':
normalized_constant = tf.get_variable(
"ebm_normalized_constant",
shape=[config.max_position_embeddings],
initializer=tf.ones_initializer())
tf.logging.info("****** one_constant logz *******")
valid_seq_length = tf.cast(tf.reduce_sum(input_mask, axis=-1), tf.int32) # batch_size
onehot_length_ids = tf.one_hot(valid_seq_length, config.max_position_embeddings)
input_normalized_constant = tf.einsum("ab,b->a", tf.cast(onehot_length_ids, tf.float32), normalized_constant)
elif kargs.get("normalized_constant", "constant") == 'constant_constant':
normalized_constant = tf.get_variable(
"ebm_normalized_constant",
shape=[config.max_position_embeddings],
initializer=tf.constant_initializer(np.ones((config.max_position_embeddings))*200.0, tf.float32))
tf.logging.info("****** one_constant logz *******")
valid_seq_length = tf.cast(tf.reduce_sum(input_mask, axis=-1), tf.int32) # batch_size
onehot_length_ids = tf.one_hot(valid_seq_length, config.max_position_embeddings)
input_normalized_constant = tf.einsum("ab,b->a", tf.cast(onehot_length_ids, tf.float32), normalized_constant)
elif kargs.get("normalized_constant", "constant") == 'log9_constant':
normalized_constant = tf.get_variable(
"ebm_normalized_constant",
shape=[config.max_position_embeddings],
initializer=tf.constant_initializer(np.ones((config.max_position_embeddings))*np.log(9.0), tf.float32))
tf.logging.info("****** one_constant logz *******")
valid_seq_length = tf.cast(tf.reduce_sum(input_mask, axis=-1), tf.int32) # batch_size
onehot_length_ids = tf.one_hot(valid_seq_length, config.max_position_embeddings)
input_normalized_constant = tf.einsum("ab,b->a", tf.cast(onehot_length_ids, tf.float32), normalized_constant)
elif kargs.get("normalized_constant", "constant") == 'logv_constant':
normalized_constant = tf.get_variable(
"ebm_normalized_constant",
shape=[config.max_position_embeddings],
initializer=tf.constant_initializer(np.ones((config.max_position_embeddings))*np.log(config.vocab_size), tf.float32))
tf.logging.info("****** one_constant logz *******")
valid_seq_length = tf.cast(tf.reduce_sum(input_mask, axis=-1), tf.int32) # batch_size
onehot_length_ids = tf.one_hot(valid_seq_length, config.max_position_embeddings)
input_normalized_constant = tf.einsum("ab,b->a", tf.cast(onehot_length_ids, tf.float32), normalized_constant)
elif kargs.get("normalized_constant", "constant") == 'logv_constant_ln':
normalized_constant = tf.get_variable(
"ebm_normalized_constant",
shape=[],
initializer=tf.constant_initializer(np.log(config.vocab_size), tf.float32))
input_normalized_constant = normalized_constant
elif kargs.get("normalized_constant", "length_linear") == 'length_linear':
normalized_constant = tf.get_variable(
"ebm_normalized_constant",
shape=[config.max_position_embeddings],
initializer=tf.constant_initializer(np.arange((config.max_position_embeddings))+1, tf.float32),
trainable=False)
scale_weights = tf.get_variable(
"ebm_normalized_constant_scale",
shape=[config.max_position_embeddings],
initializer=tf.constant_initializer(np.log(config.vocab_size)*np.ones((config.max_position_embeddings)), dtype=tf.float32),
trainable=True)
scale_bias = tf.get_variable(
"ebm_normalized_constant_bias",
shape=[config.max_position_embeddings],
initializer=tf.zeros_initializer(),
trainable=True)
tf.logging.info("****** length linear logz *******")
# normalized_constant = scale_bias + scale_weights * tf.pow(normalized_constant, 2)
valid_seq_length = tf.cast(tf.reduce_sum(input_mask, axis=-1), tf.int32) # batch_size
onehot_length_ids = tf.one_hot(valid_seq_length, config.max_position_embeddings)
length_part = tf.einsum("ab,b->a", tf.cast(onehot_length_ids, tf.float32), normalized_constant)
length_scale_part = tf.einsum("ab,b->a", tf.cast(onehot_length_ids, tf.float32), scale_weights)
length_bias_part = tf.einsum("ab,b->a", tf.cast(onehot_length_ids, tf.float32), scale_bias)
input_normalized_constant = length_part*length_scale_part + length_bias_part
# input_normalized_constant = tf.einsum("ab,b->a", tf.cast(onehot_length_ids, tf.float32), normalized_constant)
# f_input_mask = tf.cast(tf.expand_dims(input_mask, axis=-1), tf.float32)
if kargs.get("energy_pooling", "mi") == "mean_pooling":
tf.logging.info("==apply mean pooling to get hidden states projections==")
# for input token sequence: <start> a b c
# we only calculate energy on a,b,c which <start> can't contribute to final
# energy function
# batch x dim
pool_features = tf.einsum("abc,ab->ac", input_tensor[:, 1:], tf.cast(input_mask[:, 1:], tf.float32))
pool_features /= (1e-10+tf.reduce_sum(tf.cast(input_mask[:, 1:], tf.float32), axis=1, keepdims=True))
# tf.reduce_sum(input_tensor*f_input_mask, axis=1) #/ (1e-10+tf.reduce_sum(f_input_mask, axis=1))
print(pool_features.get_shape(), "===pool_features shape===")
elif kargs.get("energy_pooling", "mi") == "mi":
tf.logging.info("==apply mi to get hidden states projections==")
# input_tensor_norm = tf.expand_dims(tf.sqrt(tf.reduce_sum(tf.pow(input_tensor, 2), axis=-1))+1e-20, axis=-1)
# input_tensor = input_tensor / tf.stop_gradient(input_tensor_norm)
# output_weights_norm = tf.expand_dims(tf.sqrt(tf.reduce_sum(tf.pow(output_weights, 2), axis=-1))+1e-20, axis=-1)
# output_weights = output_weights / tf.stop_gradient(output_weights_norm)
# we calculate cosine distance to make mi bounded by [-1, 1]
logits = tf.einsum("abc,dc->abd", input_tensor, output_weights) # batch x seq x vocab
logits = tf.nn.bias_add(logits, output_bias)
input_id_shape = bert_utils.get_shape_list(input_ids, [2,3])
if len(input_id_shape) == 2:
onehot_input_ids = tf.cast(tf.one_hot(tf.cast(input_ids, tf.int32), config.vocab_size), tf.float32) # batch x seq x vocab
input_ori_ids = tf.cast(onehot_input_ids, tf.float32)
print("==input ori ids shape== 2-dim", input_ori_ids.get_shape())
else:
input_ori_ids = tf.cast(input_ids, tf.float32)
print("==input ori ids shape== 3-dim", input_ori_ids.get_shape())
logits = tf.einsum("abd,abd->ab", logits, input_ori_ids)
print(logits.get_shape(), "==pooled logits shape==")
# with l2-normalize, we can bound logits to 1
pool_features = tf.reduce_sum(logits[:, 1:]*tf.cast(input_mask[:, 1:], tf.float32), axis=1) #/ (1e-10+tf.reduce_sum(tf.cast(input_mask[:, 1:], tf.float32), axis=1))
pool_features = tf.expand_dims(pool_features, axis=-1)
print(pool_features.get_shape(), "==pooled feature shape==")
if kargs.get("softplus_features", False):
# when pooled_features is to infinite, it converges to 0
# when is to minus inifinite, it will converges to inifite
pool_features = tf.nn.softplus(-pool_features)
tf.logging.info("****** apply softplus transformation for pooled_features *******")
elif kargs.get("energy_pooling", "mi") == "cls":
with tf.variable_scope("transform"):
pool_features = tf.layers.dense(
input_tensor,
units=1,
use_bias=False,
activation=None
)
tf.logging.info("****** apply linear transformation for pooled_features *******")
# batch_size x hidden_dims
if kargs.get('transform', True):
if kargs.get("transformer_activation", "none") == 'softplus':
with tf.variable_scope("transform"):
ebm_scalar = tf.layers.dense(
pool_features,
units=1,
use_bias=True,
activation=tf.nn.softplus # mask scalar to [0,inifite]
)
tf.logging.info("****** apply softplus *******")
elif kargs.get("transformer_activation", "none") == 'linear':
tf.logging.info("****** apply linear projection *******")
with tf.variable_scope("transform"):
ebm_scalar = tf.layers.dense(
pool_features,
units=1,
use_bias=True,
activation=None # mask scalar to [0,inifite]
)
else:
with tf.variable_scope("transform"):
feature_shape = bert_utils.get_shape_list(pool_features, expected_rank=[1,2])
pool_features = tf.layers.dense(
pool_features,
units=feature_shape[-1],
activation=tf.nn.relu,
)
output_weights = tf.get_variable(
"output_weights", [config.max_position_embeddings, feature_shape[-1]],
initializer=tf.truncated_normal_initializer(stddev=0.02))
output_bias = tf.get_variable(
"output_bias", [config.max_position_embeddings],
initializer=tf.constant_initializer(-np.log(np.arange(config.max_position_embeddings).astype(np.float32)+1.0), dtype=tf.float32)
)
# batch x max_position_embeddings
ebm_scalar_pos = tf.nn.relu(tf.matmul(pool_features, output_weights, transpose_b=True)) + output_bias
pos_tensor = tf.cast(tf.reduce_sum(tf.cast(input_mask, tf.float32), axis=-1), tf.int32)
onehot_pos = tf.cast(tf.one_hot(tf.cast(pos_tensor, tf.int32), config.max_position_embeddings), tf.float32) # batch x seq x vocab
ebm_scalar = tf.einsum("ab,ab->a", ebm_scalar_pos, onehot_pos)
ebm_scalar = tf.expand_dims(ebm_scalar, axis=-1)
tf.logging.info("****** apply linear projection *******")
print("===ebm_scalar====", ebm_scalar.get_shape())
ebm_scalar = tf.squeeze(ebm_scalar, axis=-1)
print("===ebm_scalar====", ebm_scalar.get_shape())
# ebm_scalar /= (1e-10+tf.reduce_sum(tf.cast(input_mask, tf.float32), axis=-1))
# if kargs.get("energy_pooling", "mi") == "mean_pooling":
print("===ebm_scalar====", ebm_scalar.get_shape())
print("===input_normalized_constant====", input_normalized_constant.get_shape())
else:
ebm_scalar = tf.squeeze(pool_features, axis=-1)
# ebm_scalar /= (1e-10+tf.reduce_sum(tf.cast(input_mask, tf.float32), axis=-1))
print("===ebm_scalar====", ebm_scalar.get_shape())
print("===input_normalized_constant====", input_normalized_constant.get_shape())
if not kargs.get("prob_ln", False):
tf.logging.info("****** sum of plogprob as sentence probability *******")
# ebm_scalar /= (1e-10+tf.reduce_sum(tf.cast(input_mask, tf.float32), axis=-1))
else:
ebm_scalar /= (1e-10+tf.reduce_sum(tf.cast(input_mask[:, 1:], tf.float32), axis=-1))
tf.logging.info("****** sum of plogprob with length normalization as sentence probability *******")
print("===ebm_scalar====", ebm_scalar.get_shape())
print("===input_normalized_constant====", input_normalized_constant.get_shape())
# original ebm log-likelihood:
# log(exp(-E(x))/Z) = -E(x) - log(Z)
# here we use bert encoder of pooled hidden states as energy function which need to minus when apply to
# actual energy function
if not kargs.get("use_tpu", False):
tf.summary.scalar('ebm_scalar',
tf.reduce_mean(ebm_scalar))
if kargs.get("logz_mode", "default") == 'default':
tf.logging.info("****** default logz *******")
logits = -ebm_scalar - input_normalized_constant - tf.log(1e-10+tf.reduce_sum(tf.cast(input_mask, tf.float32), axis=-1))
elif kargs.get("logz_mode", "default") == 'standard':
logits = ebm_scalar - input_normalized_constant
tf.logging.info("****** standard logz *******")
elif kargs.get("logz_mode", "default") == 'standard_minus':
tf.logging.info("****** minus standard logz *******")
logits = -ebm_scalar - input_normalized_constant
elif kargs.get("logz_mode", "default") == 'constant':
logits = -ebm_scalar - tf.log(1e-10+tf.reduce_sum(tf.cast(input_mask, tf.float32), axis=-1))
tf.logging.info("****** constant logz *******")
elif kargs.get("logz_mode", "self_normalizing") == 'self_normalizing':
logits = -ebm_scalar
tf.logging.info("****** self_normalizing *******")
elif kargs.get("logz_mode", "none") == 'none':
logits = ebm_scalar
tf.logging.info("****** none logz *******")
else:
tf.logging.info("****** linear logz *******")
logits = ebm_scalar - input_normalized_constant * tf.reduce_sum(tf.cast(input_mask, tf.float32), axis=-1)
print("=ebm logits shape==", logits.get_shape())
return logits