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Commit 6ce292df authored by Frederick Liu's avatar Frederick Liu Committed by A. Unique TensorFlower
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[tfnlp] Remove nlp/transformer as we moved all usage to legacy/transformer 

please use Seq2SeqTransformer in tfnlp instead.

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official/nlp/transformer/transformer_main_test.py deleted 100644 → 0
View file @ d78ec6ea
# Copyright 2021 The TensorFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Test Transformer model."""
import os
import re
import sys
import unittest
from absl import flags
from absl.testing import flagsaver
import tensorflow as tf
from tensorflow.python.eager import context # pylint: disable=ungrouped-imports
from official.nlp.transformer import misc
from official.nlp.transformer import transformer_main
FLAGS = flags.FLAGS
FIXED_TIMESTAMP = 'my_time_stamp'
WEIGHT_PATTERN = re.compile(r'weights-epoch-.+\.hdf5')
def _generate_file(filepath, lines):
with open(filepath, 'w') as f:
for l in lines:
f.write('{}\n'.format(l))
class TransformerTaskTest(tf.test.TestCase):
local_flags = None
def setUp(self): # pylint: disable=g-missing-super-call
temp_dir = self.get_temp_dir()
if TransformerTaskTest.local_flags is None:
misc.define_transformer_flags()
# Loads flags, array cannot be blank.
flags.FLAGS(['foo'])
TransformerTaskTest.local_flags = flagsaver.save_flag_values()
else:
flagsaver.restore_flag_values(TransformerTaskTest.local_flags)
FLAGS.model_dir = os.path.join(temp_dir, FIXED_TIMESTAMP)
FLAGS.param_set = 'tiny'
FLAGS.use_synthetic_data = True
FLAGS.steps_between_evals = 1
FLAGS.train_steps = 1
FLAGS.validation_steps = 1
FLAGS.batch_size = 4
FLAGS.max_length = 1
FLAGS.num_gpus = 1
FLAGS.distribution_strategy = 'off'
FLAGS.dtype = 'fp32'
self.model_dir = FLAGS.model_dir
self.temp_dir = temp_dir
self.vocab_file = os.path.join(temp_dir, 'vocab')
self.vocab_size = misc.get_model_params(FLAGS.param_set, 0)['vocab_size']
self.bleu_source = os.path.join(temp_dir, 'bleu_source')
self.bleu_ref = os.path.join(temp_dir, 'bleu_ref')
self.orig_policy = (
tf.compat.v2.keras.mixed_precision.global_policy())
def tearDown(self): # pylint: disable=g-missing-super-call
tf.compat.v2.keras.mixed_precision.set_global_policy(self.orig_policy)
def _assert_exists(self, filepath):
self.assertTrue(os.path.exists(filepath))
def test_train_no_dist_strat(self):
if context.num_gpus() >= 2:
self.skipTest('No need to test 2+ GPUs without a distribution strategy.')
t = transformer_main.TransformerTask(FLAGS)
t.train()
def test_train_save_full_model(self):
if context.num_gpus() >= 2:
self.skipTest('No need to test 2+ GPUs without a distribution strategy.')
FLAGS.save_weights_only = False
t = transformer_main.TransformerTask(FLAGS)
t.train()
def test_train_static_batch(self):
if context.num_gpus() >= 2:
self.skipTest('No need to test 2+ GPUs without a distribution strategy.')
FLAGS.distribution_strategy = 'one_device'
if tf.test.is_built_with_cuda():
FLAGS.num_gpus = 1
else:
FLAGS.num_gpus = 0
FLAGS.static_batch = True
t = transformer_main.TransformerTask(FLAGS)
t.train()
@unittest.skipUnless(tf.test.is_built_with_cuda(), 'requires GPU')
def test_train_1_gpu_with_dist_strat(self):
FLAGS.distribution_strategy = 'one_device'
t = transformer_main.TransformerTask(FLAGS)
t.train()
@unittest.skipUnless(tf.test.is_built_with_cuda(), 'requires GPU')
def test_train_fp16(self):
FLAGS.distribution_strategy = 'one_device'
FLAGS.dtype = 'fp16'
t = transformer_main.TransformerTask(FLAGS)
t.train()
@unittest.skipUnless(tf.test.is_built_with_cuda(), 'requires GPU')
def test_train_2_gpu(self):
if context.num_gpus() < 2:
self.skipTest(
'{} GPUs are not available for this test. {} GPUs are available'
.format(2, context.num_gpus()))
FLAGS.distribution_strategy = 'mirrored'
FLAGS.num_gpus = 2
FLAGS.param_set = 'base'
t = transformer_main.TransformerTask(FLAGS)
t.train()
@unittest.skipUnless(tf.test.is_built_with_cuda(), 'requires GPU')
def test_train_2_gpu_fp16(self):
if context.num_gpus() < 2:
self.skipTest(
'{} GPUs are not available for this test. {} GPUs are available'
.format(2, context.num_gpus()))
FLAGS.distribution_strategy = 'mirrored'
FLAGS.num_gpus = 2
FLAGS.param_set = 'base'
FLAGS.dtype = 'fp16'
t = transformer_main.TransformerTask(FLAGS)
t.train()
def _prepare_files_and_flags(self, *extra_flags):
# Make log dir.
if not os.path.exists(self.temp_dir):
os.makedirs(self.temp_dir)
# Fake vocab, bleu_source and bleu_ref.
tokens = [
"'<pad>'", "'<EOS>'", "'_'", "'a'", "'b'", "'c'", "'d'", "'a_'", "'b_'",
"'c_'", "'d_'"
]
tokens += ["'{}'".format(i) for i in range(self.vocab_size - len(tokens))]
_generate_file(self.vocab_file, tokens)
_generate_file(self.bleu_source, ['a b', 'c d'])
_generate_file(self.bleu_ref, ['a b', 'd c'])
# Update flags.
update_flags = [
'ignored_program_name',
'--vocab_file={}'.format(self.vocab_file),
'--bleu_source={}'.format(self.bleu_source),
'--bleu_ref={}'.format(self.bleu_ref),
]
if extra_flags:
update_flags.extend(extra_flags)
FLAGS(update_flags)
def test_predict(self):
if context.num_gpus() >= 2:
self.skipTest('No need to test 2+ GPUs without a distribution strategy.')
self._prepare_files_and_flags()
t = transformer_main.TransformerTask(FLAGS)
t.predict()
@unittest.skipUnless(tf.test.is_built_with_cuda(), 'requires GPU')
def test_predict_fp16(self):
if context.num_gpus() >= 2:
self.skipTest('No need to test 2+ GPUs without a distribution strategy.')
self._prepare_files_and_flags('--dtype=fp16')
t = transformer_main.TransformerTask(FLAGS)
t.predict()
def test_eval(self):
if context.num_gpus() >= 2:
self.skipTest('No need to test 2+ GPUs without a distribution strategy.')
if 'test_xla' in sys.argv[0]:
self.skipTest('TODO(xla): Make this test faster under XLA.')
self._prepare_files_and_flags()
t = transformer_main.TransformerTask(FLAGS)
t.eval()
if __name__ == '__main__':
tf.test.main()
official/nlp/transformer/transformer_test.py deleted 100644 → 0
View file @ d78ec6ea
# Copyright 2021 The TensorFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Test Transformer model."""
import tensorflow as tf
from official.nlp.transformer import model_params
from official.nlp.transformer import transformer
class TransformerV2Test(tf.test.TestCase):
def setUp(self):
super().setUp()
self.params = params = model_params.TINY_PARAMS
params["batch_size"] = params["default_batch_size"] = 16
params["use_synthetic_data"] = True
params["hidden_size"] = 12
params["num_hidden_layers"] = 2
params["filter_size"] = 14
params["num_heads"] = 2
params["vocab_size"] = 41
params["extra_decode_length"] = 2
params["beam_size"] = 3
params["dtype"] = tf.float32
def test_create_model_train(self):
model = transformer.create_model(self.params, True)
inputs, outputs = model.inputs, model.outputs
self.assertEqual(len(inputs), 2)
self.assertEqual(len(outputs), 1)
self.assertEqual(inputs[0].shape.as_list(), [None, None])
self.assertEqual(inputs[0].dtype, tf.int64)
self.assertEqual(inputs[1].shape.as_list(), [None, None])
self.assertEqual(inputs[1].dtype, tf.int64)
self.assertEqual(outputs[0].shape.as_list(), [None, None, 41])
self.assertEqual(outputs[0].dtype, tf.float32)
def test_create_model_not_train(self):
model = transformer.create_model(self.params, False)
inputs, outputs = model.inputs, model.outputs
self.assertEqual(len(inputs), 1)
self.assertEqual(len(outputs), 2)
self.assertEqual(inputs[0].shape.as_list(), [None, None])
self.assertEqual(inputs[0].dtype, tf.int64)
self.assertEqual(outputs[0].shape.as_list(), [None, None])
self.assertEqual(outputs[0].dtype, tf.int32)
self.assertEqual(outputs[1].shape.as_list(), [None])
self.assertEqual(outputs[1].dtype, tf.float32)
def test_export(self):
model = transformer.Transformer(self.params, name="transformer_v2")
export_dir = self.get_temp_dir()
batch_size = 5
max_length = 6
class SaveModule(tf.Module):
def __init__(self, model):
super(SaveModule, self).__init__()
self.model = model
@tf.function
def serve(self, x):
return self.model.call([x], training=False)
save_module = SaveModule(model)
tensor_shape = (None, None)
sample_input = tf.zeros((batch_size, max_length), dtype=tf.int64)
_ = save_module.serve(sample_input)
signatures = dict(
serving_default=save_module.serve.get_concrete_function(
tf.TensorSpec(shape=tensor_shape, dtype=tf.int64, name="x")))
tf.saved_model.save(save_module, export_dir, signatures=signatures)
imported = tf.saved_model.load(export_dir)
serving_fn = imported.signatures["serving_default"]
all_outputs = serving_fn(sample_input)
output = all_outputs["outputs"]
output_shapes = output.shape.as_list()
self.assertEqual(output_shapes[0], batch_size)
self.assertEqual(output_shapes[1],
max_length + model.params["extra_decode_length"])
if __name__ == "__main__":
tf.test.main()
official/nlp/transformer/translate.py deleted 100644 → 0
View file @ d78ec6ea
# Copyright 2021 The TensorFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Translate text or files using trained transformer model."""
# Import libraries
from absl import logging
import numpy as np
import tensorflow as tf
from official.nlp.transformer.utils import tokenizer
_EXTRA_DECODE_LENGTH = 100
_BEAM_SIZE = 4
_ALPHA = 0.6
def _get_sorted_inputs(filename):
"""Read and sort lines from the file sorted by decreasing length.
Args:
filename: String name of file to read inputs from.
Returns:
Sorted list of inputs, and dictionary mapping original index->sorted index
of each element.
"""
with tf.io.gfile.GFile(filename) as f:
records = f.read().split("\n")
inputs = [record.strip() for record in records]
if not inputs[-1]:
inputs.pop()
input_lens = [(i, len(line.split())) for i, line in enumerate(inputs)]
sorted_input_lens = sorted(input_lens, key=lambda x: x[1], reverse=True)
sorted_inputs = [None] * len(sorted_input_lens)
sorted_keys = [0] * len(sorted_input_lens)
for i, (index, _) in enumerate(sorted_input_lens):
sorted_inputs[i] = inputs[index]
sorted_keys[index] = i
return sorted_inputs, sorted_keys
def _encode_and_add_eos(line, subtokenizer):
"""Encode line with subtokenizer, and add EOS id to the end."""
return subtokenizer.encode(line) + [tokenizer.EOS_ID]
def _trim_and_decode(ids, subtokenizer):
"""Trim EOS and PAD tokens from ids, and decode to return a string."""
try:
index = list(ids).index(tokenizer.EOS_ID)
return subtokenizer.decode(ids[:index])
except ValueError: # No EOS found in sequence
return subtokenizer.decode(ids)
def translate_file(model,
params,
subtokenizer,
input_file,
output_file=None,
print_all_translations=True,
distribution_strategy=None):
"""Translate lines in file, and save to output file if specified.
Args:
model: A Keras model, used to generate the translations.
params: A dictionary, containing the translation related parameters.
subtokenizer: A subtokenizer object, used for encoding and decoding source
and translated lines.
input_file: A file containing lines to translate.
output_file: A file that stores the generated translations.
print_all_translations: A bool. If true, all translations are printed to
stdout.
distribution_strategy: A distribution strategy, used to perform inference
directly with tf.function instead of Keras model.predict().
Raises:
ValueError: if output file is invalid.
"""
batch_size = params["decode_batch_size"]
# Read and sort inputs by length. Keep dictionary (original index-->new index
# in sorted list) to write translations in the original order.
sorted_inputs, sorted_keys = _get_sorted_inputs(input_file)
total_samples = len(sorted_inputs)
num_decode_batches = (total_samples - 1) // batch_size + 1
def input_generator():
"""Yield encoded strings from sorted_inputs."""
for i in range(num_decode_batches):
lines = [
sorted_inputs[j + i * batch_size]
for j in range(batch_size)
if j + i * batch_size < total_samples
]
lines = [_encode_and_add_eos(l, subtokenizer) for l in lines]
if distribution_strategy:
for j in range(batch_size - len(lines)):
lines.append([tokenizer.EOS_ID])
batch = tf.keras.preprocessing.sequence.pad_sequences(
lines,
maxlen=params["decode_max_length"],
dtype="int32",
padding="post")
logging.info("Decoding batch %d out of %d.", i, num_decode_batches)
yield batch
@tf.function
def predict_step(inputs):
"""Decoding step function for TPU runs."""
def _step_fn(inputs):
"""Per replica step function."""
tag = inputs[0]
val_inputs = inputs[1]
val_outputs, _ = model([val_inputs], training=False)
return tag, val_outputs
return distribution_strategy.run(_step_fn, args=(inputs,))
translations = []
if distribution_strategy:
num_replicas = distribution_strategy.num_replicas_in_sync
local_batch_size = params["decode_batch_size"] // num_replicas
for i, text in enumerate(input_generator()):
if distribution_strategy:
text = np.reshape(text, [num_replicas, local_batch_size, -1])
# Add tag to the input of each replica with the reordering logic after
# outputs, to ensure the output order matches the input order.
text = tf.constant(text)
@tf.function
def text_as_per_replica():
replica_context = tf.distribute.get_replica_context()
replica_id = replica_context.replica_id_in_sync_group
return replica_id, text[replica_id] # pylint: disable=cell-var-from-loop
text = distribution_strategy.run(text_as_per_replica)
outputs = distribution_strategy.experimental_local_results(
predict_step(text))
val_outputs = [output for _, output in outputs]
val_outputs = np.reshape(val_outputs, [params["decode_batch_size"], -1])
else:
val_outputs, _ = model.predict(text)
length = len(val_outputs)
for j in range(length):
if j + i * batch_size < total_samples:
translation = _trim_and_decode(val_outputs[j], subtokenizer)
translations.append(translation)
if print_all_translations:
logging.info("Translating:\n\tInput: %s\n\tOutput: %s",
sorted_inputs[j + i * batch_size], translation)
# Write translations in the order they appeared in the original file.
if output_file is not None:
if tf.io.gfile.isdir(output_file):
raise ValueError("File output is a directory, will not save outputs to "
"file.")
logging.info("Writing to file %s", output_file)
with tf.io.gfile.GFile(output_file, "w") as f:
for i in sorted_keys:
f.write("%s\n" % translations[i])
def translate_from_text(model, subtokenizer, txt):
encoded_txt = _encode_and_add_eos(txt, subtokenizer)
result = model.predict(encoded_txt)
outputs = result["outputs"]
logging.info("Original: \"%s\"", txt)
translate_from_input(outputs, subtokenizer)
def translate_from_input(outputs, subtokenizer):
translation = _trim_and_decode(outputs, subtokenizer)
logging.info("Translation: \"%s\"", translation)
official/nlp/transformer/utils/__init__.py deleted 100644 → 0
View file @ d78ec6ea
# Copyright 2021 The TensorFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
official/nlp/transformer/utils/metrics.py deleted 100644 → 0
View file @ d78ec6ea
# Copyright 2021 The TensorFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Functions for calculating loss, accuracy, and other model metrics.
Metrics:
- Padded loss, accuracy, and negative log perplexity. Source:
https://github.com/tensorflow/tensor2tensor/blob/master/tensor2tensor/utils/metrics.py
- BLEU approximation. Source:
https://github.com/tensorflow/tensor2tensor/blob/master/tensor2tensor/utils/bleu_hook.py
- ROUGE score. Source:
https://github.com/tensorflow/tensor2tensor/blob/master/tensor2tensor/utils/rouge.py
"""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import collections
import math
import numpy as np
import six
from six.moves import xrange # pylint: disable=redefined-builtin
import tensorflow.compat.v1 as tf
def _pad_tensors_to_same_length(x, y):
"""Pad x and y so that the results have the same length (second dimension)."""
with tf.name_scope("pad_to_same_length"):
x_length = tf.shape(x)[1]
y_length = tf.shape(y)[1]
max_length = tf.maximum(x_length, y_length)
x = tf.pad(x, [[0, 0], [0, max_length - x_length], [0, 0]])
y = tf.pad(y, [[0, 0], [0, max_length - y_length]])
return x, y
def padded_cross_entropy_loss(logits, labels, smoothing, vocab_size):
"""Calculate cross entropy loss while ignoring padding.
Args:
logits: Tensor of size [batch_size, length_logits, vocab_size]
labels: Tensor of size [batch_size, length_labels]
smoothing: Label smoothing constant, used to determine the on and off values
vocab_size: int size of the vocabulary
Returns:
Returns the cross entropy loss and weight tensors: float32 tensors with
shape [batch_size, max(length_logits, length_labels)]
"""
with tf.name_scope("loss", values=[logits, labels]):
logits, labels = _pad_tensors_to_same_length(logits, labels)
# Calculate smoothing cross entropy
with tf.name_scope("smoothing_cross_entropy", values=[logits, labels]):
confidence = 1.0 - smoothing
low_confidence = (1.0 - confidence) / tf.cast(vocab_size - 1, tf.float32)
soft_targets = tf.one_hot(
tf.cast(labels, tf.int32),
depth=vocab_size,
on_value=confidence,
off_value=low_confidence)
xentropy = tf.nn.softmax_cross_entropy_with_logits_v2(
logits=logits, labels=soft_targets)
# Calculate the best (lowest) possible value of cross entropy, and
# subtract from the cross entropy loss.
normalizing_constant = -(
confidence * tf.log(confidence) + tf.cast(vocab_size - 1, tf.float32)
* low_confidence * tf.log(low_confidence + 1e-20))
xentropy -= normalizing_constant
weights = tf.cast(tf.not_equal(labels, 0), tf.float32)
return xentropy * weights, weights
def _convert_to_eval_metric(metric_fn):
"""Wrap a metric fn that returns scores and weights as an eval metric fn.
The input metric_fn returns values for the current batch. The wrapper
aggregates the return values collected over all of the batches evaluated.
Args:
metric_fn: function that returns scores and weights for the current batch's
logits and predicted labels.
Returns:
function that aggregates the scores and weights from metric_fn.
"""
def problem_metric_fn(*args):
"""Returns an aggregation of the metric_fn's returned values."""
(scores, weights) = metric_fn(*args)
# The tf.metrics.mean function assures correct aggregation.
return tf.metrics.mean(scores, weights)
return problem_metric_fn
def get_eval_metrics(logits, labels, params):
"""Return dictionary of model evaluation metrics."""
metrics = {
"accuracy": _convert_to_eval_metric(padded_accuracy)(logits, labels),
"accuracy_top5": _convert_to_eval_metric(padded_accuracy_top5)(
logits, labels),
"accuracy_per_sequence": _convert_to_eval_metric(
padded_sequence_accuracy)(logits, labels),
"neg_log_perplexity": _convert_to_eval_metric(padded_neg_log_perplexity)(
logits, labels, params["vocab_size"]),
}
if not params["use_tpu"]:
# TPU does not support tf.py_func
metrics.update({
"approx_bleu_score": _convert_to_eval_metric(
bleu_score)(logits, labels),
"rouge_2_fscore": _convert_to_eval_metric(
rouge_2_fscore)(logits, labels),
"rouge_L_fscore": _convert_to_eval_metric(
rouge_l_fscore)(logits, labels),
})
# Prefix each of the metric names with "metrics/". This allows the metric
# graphs to display under the "metrics" category in TensorBoard.
metrics = {"metrics/%s" % k: v for k, v in six.iteritems(metrics)}
return metrics
def padded_accuracy(logits, labels):
"""Percentage of times that predictions matches labels on non-0s."""
with tf.variable_scope("padded_accuracy", values=[logits, labels]):
logits, labels = _pad_tensors_to_same_length(logits, labels)
weights = tf.cast(tf.not_equal(labels, 0), tf.float32)
outputs = tf.cast(tf.argmax(logits, axis=-1), tf.int32)
padded_labels = tf.cast(labels, tf.int32)
return tf.cast(tf.equal(outputs, padded_labels), tf.float32), weights
def padded_accuracy_topk(logits, labels, k):
"""Percentage of times that top-k predictions matches labels on non-0s."""
with tf.variable_scope("padded_accuracy_topk", values=[logits, labels]):
logits, labels = _pad_tensors_to_same_length(logits, labels)
weights = tf.cast(tf.not_equal(labels, 0), tf.float32)
effective_k = tf.minimum(k, tf.shape(logits)[-1])
_, outputs = tf.nn.top_k(logits, k=effective_k)
outputs = tf.cast(outputs, tf.int32)
padded_labels = tf.cast(labels, tf.int32)
padded_labels = tf.expand_dims(padded_labels, axis=-1)
padded_labels += tf.zeros_like(outputs) # Pad to same shape.
same = tf.cast(tf.equal(outputs, padded_labels), tf.float32)
same_topk = tf.reduce_sum(same, axis=-1)
return same_topk, weights
def padded_accuracy_top5(logits, labels):
return padded_accuracy_topk(logits, labels, 5)
def padded_sequence_accuracy(logits, labels):
"""Percentage of times that predictions matches labels everywhere (non-0)."""
with tf.variable_scope("padded_sequence_accuracy", values=[logits, labels]):
logits, labels = _pad_tensors_to_same_length(logits, labels)
weights = tf.cast(tf.not_equal(labels, 0), tf.float32)
outputs = tf.cast(tf.argmax(logits, axis=-1), tf.int32)
padded_labels = tf.cast(labels, tf.int32)
not_correct = (tf.cast(tf.not_equal(outputs, padded_labels), tf.float32) *
weights)
axis = list(range(1, len(outputs.get_shape())))
correct_seq = 1.0 - tf.minimum(1.0, tf.reduce_sum(not_correct, axis=axis))
return correct_seq, tf.constant(1.0)
def padded_neg_log_perplexity(logits, labels, vocab_size):
"""Average log-perplexity excluding padding 0s. No smoothing."""
num, den = padded_cross_entropy_loss(logits, labels, 0, vocab_size)
return -num, den
def bleu_score(logits, labels):
"""Approximate BLEU score computation between labels and predictions.
An approximate BLEU scoring method since we do not glue word pieces or
decode the ids and tokenize the output. By default, we use ngram order of 4
and use brevity penalty. Also, this does not have beam search.
Args:
logits: Tensor of size [batch_size, length_logits, vocab_size]
labels: Tensor of size [batch-size, length_labels]
Returns:
bleu: int, approx bleu score
"""
predictions = tf.cast(tf.argmax(logits, axis=-1), tf.int32)
# TODO: Look into removing use of py_func # pylint: disable=g-bad-todo
bleu = tf.py_func(compute_bleu, (labels, predictions), tf.float32)
return bleu, tf.constant(1.0)
def _get_ngrams_with_counter(segment, max_order):
"""Extracts all n-grams up to a given maximum order from an input segment.
Args:
segment: text segment from which n-grams will be extracted.
max_order: maximum length in tokens of the n-grams returned by this
methods.
Returns:
The Counter containing all n-grams upto max_order in segment
with a count of how many times each n-gram occurred.
"""
ngram_counts = collections.Counter()
for order in xrange(1, max_order + 1):
for i in xrange(0, len(segment) - order + 1):
ngram = tuple(segment[i:i + order])
ngram_counts[ngram] += 1
return ngram_counts
def compute_bleu(reference_corpus, translation_corpus, max_order=4,
use_bp=True):
"""Computes BLEU score of translated segments against one or more references.
Args:
reference_corpus: list of references for each translation. Each
reference should be tokenized into a list of tokens.
translation_corpus: list of translations to score. Each translation
should be tokenized into a list of tokens.
max_order: Maximum n-gram order to use when computing BLEU score.
use_bp: boolean, whether to apply brevity penalty.
Returns:
BLEU score.
"""
reference_length = 0
translation_length = 0
bp = 1.0
geo_mean = 0
matches_by_order = [0] * max_order
possible_matches_by_order = [0] * max_order
precisions = []
for (references, translations) in zip(reference_corpus, translation_corpus):
reference_length += len(references)
translation_length += len(translations)
ref_ngram_counts = _get_ngrams_with_counter(references, max_order)
translation_ngram_counts = _get_ngrams_with_counter(translations, max_order)
overlap = dict((ngram,
min(count, translation_ngram_counts[ngram]))
for ngram, count in ref_ngram_counts.items())
for ngram in overlap:
matches_by_order[len(ngram) - 1] += overlap[ngram]
for ngram in translation_ngram_counts:
possible_matches_by_order[len(ngram) - 1] += translation_ngram_counts[
ngram]
precisions = [0] * max_order
smooth = 1.0
for i in xrange(0, max_order):
if possible_matches_by_order[i] > 0:
precisions[i] = float(matches_by_order[i]) / possible_matches_by_order[i]
if matches_by_order[i] > 0:
precisions[i] = float(matches_by_order[i]) / possible_matches_by_order[
i]
else:
smooth *= 2
precisions[i] = 1.0 / (smooth * possible_matches_by_order[i])
else:
precisions[i] = 0.0
if max(precisions) > 0:
p_log_sum = sum(math.log(p) for p in precisions if p)
geo_mean = math.exp(p_log_sum / max_order)
if use_bp:
ratio = translation_length / reference_length
bp = math.exp(1 - 1. / ratio) if ratio < 1.0 else 1.0
bleu = geo_mean * bp
return np.float32(bleu)
def rouge_2_fscore(logits, labels):
"""ROUGE-2 F1 score computation between labels and predictions.
This is an approximate ROUGE scoring method since we do not glue word pieces
or decode the ids and tokenize the output.
Args:
logits: tensor, model predictions
labels: tensor, gold output.
Returns:
rouge2_fscore: approx rouge-2 f1 score.
"""
predictions = tf.cast(tf.argmax(logits, axis=-1), tf.int32)
# TODO: Look into removing use of py_func # pylint: disable=g-bad-todo
rouge_2_f_score = tf.py_func(rouge_n, (predictions, labels), tf.float32)
return rouge_2_f_score, tf.constant(1.0)
def _get_ngrams(n, text):
"""Calculates n-grams.
Args:
n: which n-grams to calculate
text: An array of tokens
Returns:
A set of n-grams
"""
ngram_set = set()
text_length = len(text)
max_index_ngram_start = text_length - n
for i in range(max_index_ngram_start + 1):
ngram_set.add(tuple(text[i:i + n]))
return ngram_set
def rouge_n(eval_sentences, ref_sentences, n=2):
"""Computes ROUGE-N f1 score of two text collections of sentences.
Source: https://www.microsoft.com/en-us/research/publication/
rouge-a-package-for-automatic-evaluation-of-summaries/
Args:
eval_sentences: Predicted sentences.
ref_sentences: Sentences from the reference set
n: Size of ngram. Defaults to 2.
Returns:
f1 score for ROUGE-N
"""
f1_scores = []
for eval_sentence, ref_sentence in zip(eval_sentences, ref_sentences):
eval_ngrams = _get_ngrams(n, eval_sentence)
ref_ngrams = _get_ngrams(n, ref_sentence)
ref_count = len(ref_ngrams)
eval_count = len(eval_ngrams)
# Count the overlapping ngrams between evaluated and reference
overlapping_ngrams = eval_ngrams.intersection(ref_ngrams)
overlapping_count = len(overlapping_ngrams)
# Handle edge case. This isn't mathematically correct, but it's good enough
if eval_count == 0:
precision = 0.0
else:
precision = float(overlapping_count) / eval_count
if ref_count == 0:
recall = 0.0
else:
recall = float(overlapping_count) / ref_count
f1_scores.append(2.0 * ((precision * recall) / (precision + recall + 1e-8)))
# return overlapping_count / reference_count
return np.mean(f1_scores, dtype=np.float32)
def rouge_l_fscore(predictions, labels):
"""ROUGE scores computation between labels and predictions.
This is an approximate ROUGE scoring method since we do not glue word pieces
or decode the ids and tokenize the output.
Args:
predictions: tensor, model predictions
labels: tensor, gold output.
Returns:
rouge_l_fscore: approx rouge-l f1 score.
"""
outputs = tf.cast(tf.argmax(predictions, axis=-1), tf.int32)
rouge_l_f_score = tf.py_func(rouge_l_sentence_level, (outputs, labels),
tf.float32)
return rouge_l_f_score, tf.constant(1.0)
def rouge_l_sentence_level(eval_sentences, ref_sentences):
"""Computes ROUGE-L (sentence level) of two collections of sentences.
Source: https://www.microsoft.com/en-us/research/publication/
rouge-a-package-for-automatic-evaluation-of-summaries/
Calculated according to:
R_lcs = LCS(X,Y)/m
P_lcs = LCS(X,Y)/n
F_lcs = ((1 + beta^2)*R_lcs*P_lcs) / (R_lcs + (beta^2) * P_lcs)
where:
X = reference summary
Y = Candidate summary
m = length of reference summary
n = length of candidate summary
Args:
eval_sentences: The sentences that have been picked by the summarizer
ref_sentences: The sentences from the reference set
Returns:
A float: F_lcs
"""
f1_scores = []
for eval_sentence, ref_sentence in zip(eval_sentences, ref_sentences):
m = float(len(ref_sentence))
n = float(len(eval_sentence))
lcs = _len_lcs(eval_sentence, ref_sentence)
f1_scores.append(_f_lcs(lcs, m, n))
return np.mean(f1_scores, dtype=np.float32)
def _len_lcs(x, y):
"""Returns the length of the Longest Common Subsequence between two seqs.
Source: http://www.algorithmist.com/index.php/Longest_Common_Subsequence
Args:
x: sequence of words
y: sequence of words
Returns
integer: Length of LCS between x and y
"""
table = _lcs(x, y)
n, m = len(x), len(y)
return table[n, m]
def _lcs(x, y):
"""Computes the length of the LCS between two seqs.
The implementation below uses a DP programming algorithm and runs
in O(nm) time where n = len(x) and m = len(y).
Source: http://www.algorithmist.com/index.php/Longest_Common_Subsequence
Args:
x: collection of words
y: collection of words
Returns:
Table of dictionary of coord and len lcs
"""
n, m = len(x), len(y)
table = dict()
for i in range(n + 1):
for j in range(m + 1):
if i == 0 or j == 0:
table[i, j] = 0
elif x[i - 1] == y[j - 1]:
table[i, j] = table[i - 1, j - 1] + 1
else:
table[i, j] = max(table[i - 1, j], table[i, j - 1])
return table
def _f_lcs(llcs, m, n):
"""Computes the LCS-based F-measure score.
Source: http://research.microsoft.com/en-us/um/people/cyl/download/papers/
rouge-working-note-v1.3.1.pdf
Args:
llcs: Length of LCS
m: number of words in reference summary
n: number of words in candidate summary
Returns:
Float. LCS-based F-measure score
"""
r_lcs = llcs / m
p_lcs = llcs / n
beta = p_lcs / (r_lcs + 1e-12)
num = (1 + (beta ** 2)) * r_lcs * p_lcs
denom = r_lcs + ((beta ** 2) * p_lcs)
f_lcs = num / (denom + 1e-12)
return f_lcs
official/nlp/transformer/utils/tokenizer.py deleted 100644 → 0
View file @ d78ec6ea
# Copyright 2021 The TensorFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Defines Subtokenizer class to encode and decode strings."""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import collections
import re
import sys
import unicodedata
from absl import logging
import numpy as np
import six
from six.moves import xrange # pylint: disable=redefined-builtin
import tensorflow as tf
# pylint: disable=g-complex-comprehension
PAD = "<pad>"
PAD_ID = 0
EOS = "<EOS>"
EOS_ID = 1
RESERVED_TOKENS = [PAD, EOS]
# Set of characters that will be used in the function _escape_token() (see func
# docstring for more details).
# This set is added to the alphabet list to ensure that all escaped tokens can
# be encoded.
_ESCAPE_CHARS = set(u"\\_u;0123456789")
# Regex for the function _unescape_token(), the inverse of _escape_token().
# This is used to find "\u", "\\", and "\###;" substrings in the token.
_UNESCAPE_REGEX = re.compile(r"\\u|\\\\|\\([0-9]+);")
_UNDEFINED_UNICODE = u"\u3013"
def alphanumeric_char_set():
return set(
six.unichr(i)
for i in xrange(sys.maxunicode)
if (unicodedata.category(six.unichr(i)).startswith("L") or
unicodedata.category(six.unichr(i)).startswith("N")))
# Set contains all letter and number characters.
_ALPHANUMERIC_CHAR_SET = alphanumeric_char_set()
# min_count is the minimum number of times a subtoken must appear in the data
# before before it is added to the vocabulary. The value is found using binary
# search to obtain the target vocabulary size.
_MIN_MIN_COUNT = 1 # min value to use when binary searching for min_count
_MAX_MIN_COUNT = 1000 # max value to use when binary searching for min_count
class Subtokenizer(object):
"""Encodes and decodes strings to/from integer IDs."""
def __init__(self, vocab_file, reserved_tokens=None, master_char_set=None):
"""Initializes class, creating a vocab file if data_files is provided."""
logging.info("Initializing Subtokenizer from file %s.", vocab_file)
if master_char_set is None:
master_char_set = _ALPHANUMERIC_CHAR_SET
if reserved_tokens is None:
reserved_tokens = RESERVED_TOKENS
self.subtoken_list = _load_vocab_file(vocab_file, reserved_tokens)
self.alphabet = _generate_alphabet_dict(self.subtoken_list)
self.subtoken_to_id_dict = _list_to_index_dict(self.subtoken_list)
self.max_subtoken_length = 0
for subtoken in self.subtoken_list:
self.max_subtoken_length = max(self.max_subtoken_length, len(subtoken))
# Create cache to speed up subtokenization
self._cache_size = 2**20
self._cache = [(None, None)] * self._cache_size
self._master_char_set = master_char_set
@staticmethod
def init_from_files(vocab_file,
files,
target_vocab_size,
threshold,
min_count=None,
file_byte_limit=1e6,
reserved_tokens=None,
correct_strip=True,
master_char_set=None):
"""Create subtoken vocabulary based on files, and save vocab to file.
Args:
vocab_file: String name of vocab file to store subtoken vocabulary.
files: List of file paths that will be used to generate vocabulary.
target_vocab_size: target vocabulary size to generate.
threshold: int threshold of vocabulary size to accept.
min_count: int minimum count to use for generating the vocabulary. The min
count is the minimum number of times a subtoken should appear in the
files before it is added to the vocabulary. If set to none, this value
is found using binary search.
file_byte_limit: (Default 1e6) Maximum number of bytes of sample text that
will be drawn from the files.
reserved_tokens: List of string tokens that are guaranteed to be at the
beginning of the subtoken vocabulary list.
correct_strip: Whether to convert text to unicode before strip.
master_char_set: the char set.
Returns:
Subtokenizer object
"""
if master_char_set is None:
master_char_set = _ALPHANUMERIC_CHAR_SET
if reserved_tokens is None:
reserved_tokens = RESERVED_TOKENS
if tf.io.gfile.exists(vocab_file):
logging.info("Vocab file already exists (%s)", vocab_file)
else:
logging.info("Begin steps to create subtoken vocabulary...")
token_counts = _count_tokens(files, file_byte_limit, correct_strip,
master_char_set)
alphabet = _generate_alphabet_dict(token_counts)
subtoken_list = _generate_subtokens_with_target_vocab_size(
token_counts, alphabet, target_vocab_size, threshold, min_count,
reserved_tokens)
logging.info("Generated vocabulary with %d subtokens.",
len(subtoken_list))
_save_vocab_file(vocab_file, subtoken_list)
return Subtokenizer(vocab_file, master_char_set=master_char_set)
def encode(self, raw_string, add_eos=False):
"""Encodes a string into a list of int subtoken ids."""
ret = []
tokens = _split_string_to_tokens(
native_to_unicode(raw_string), self._master_char_set)
for token in tokens:
ret.extend(self._token_to_subtoken_ids(token))
if add_eos:
assert EOS in self.subtoken_list, \
"Can't append 'EOS' because it is not in list of known subtokens."
ret.append(EOS_ID)
return ret
def _token_to_subtoken_ids(self, token):
"""Encode a single token into a list of subtoken ids."""
cache_location = hash(token) % self._cache_size
cache_key, cache_value = self._cache[cache_location]
if cache_key == token:
return cache_value
ret = _split_token_to_subtokens(
_escape_token(token, self.alphabet), self.subtoken_to_id_dict,
self.max_subtoken_length)
ret = [self.subtoken_to_id_dict[subtoken_id] for subtoken_id in ret]
self._cache[cache_location] = (token, ret)
return ret
def decode(self, subtokens):
"""Converts list of int subtokens ids into a string."""
if isinstance(subtokens, np.ndarray):
# Note that list(subtokens) converts subtokens to a python list, but the
# items remain as np.int32. This converts both the array and its items.
subtokens = subtokens.tolist()
if not subtokens:
return ""
assert isinstance(subtokens, list) and isinstance(subtokens[0], int), (
"Subtokens argument passed into decode() must be a list of integers.")
return _unicode_to_native(
_join_tokens_to_string(
self._subtoken_ids_to_tokens(subtokens), self._master_char_set))
def _subtoken_ids_to_tokens(self, subtokens):
"""Convert list of int subtoken ids to a list of string tokens."""
escaped_tokens = "".join([
self.subtoken_list[s] for s in subtokens if s < len(self.subtoken_list)
])
escaped_tokens = escaped_tokens.split("_")
# All tokens in the vocabulary list have been escaped (see _escape_token())
# so each token must be unescaped when decoding.
ret = []
for token in escaped_tokens:
if token:
ret.append(_unescape_token(token))
return ret
def _save_vocab_file(vocab_file, subtoken_list):
"""Save subtokens to file."""
with tf.io.gfile.GFile(vocab_file, mode="w") as f:
for subtoken in subtoken_list:
f.write("'%s'\n" % _unicode_to_native(subtoken))
def _load_vocab_file(vocab_file, reserved_tokens=None):
"""Load vocabulary while ensuring reserved tokens are at the top."""
if reserved_tokens is None:
reserved_tokens = RESERVED_TOKENS
subtoken_list = []
with tf.io.gfile.GFile(vocab_file, mode="r") as f:
for line in f:
subtoken = native_to_unicode(line.strip())
subtoken = subtoken[1:-1] # Remove surrounding single-quotes
if subtoken in reserved_tokens:
continue
subtoken_list.append(native_to_unicode(subtoken))
return reserved_tokens + subtoken_list
def native_to_unicode(s):
"""Convert string to unicode (required in Python 2)."""
try: # Python 2
return s if isinstance(s, unicode) else s.decode("utf-8")
except NameError: # Python 3
return s
def _unicode_to_native(s):
"""Convert string from unicode to native format (required in Python 2)."""
try: # Python 2
return s.encode("utf-8") if isinstance(s, unicode) else s
except NameError: # Python 3
return s
def _split_string_to_tokens(text, master_char_set):
"""Splits text to a list of string tokens."""
if not text:
return []
ret = []
token_start = 0
# Classify each character in the input string
is_master = [c in master_char_set for c in text]
for pos in xrange(1, len(text)):
if is_master[pos] != is_master[pos - 1]:
token = text[token_start:pos]
if token != u" " or token_start == 0:
ret.append(token)
token_start = pos
final_token = text[token_start:]
ret.append(final_token)
return ret
def _join_tokens_to_string(tokens, master_char_set):
"""Join a list of string tokens into a single string."""
token_is_master = [t[0] in master_char_set for t in tokens]
ret = []
for i, token in enumerate(tokens):
if i > 0 and token_is_master[i - 1] and token_is_master[i]:
ret.append(u" ")
ret.append(token)
return "".join(ret)
def _escape_token(token, alphabet):
r"""Replace characters that aren't in the alphabet and append "_" to token.
Apply three transformations to the token:
1. Replace underline character "_" with "\u", and backslash "\" with "\\".
2. Replace characters outside of the alphabet with "\###;", where ### is the
character's Unicode code point.
3. Appends "_" to mark the end of a token.
Args:
token: unicode string to be escaped
alphabet: list of all known characters
Returns:
escaped string
"""
token = token.replace(u"\\", u"\\\\").replace(u"_", u"\\u")
ret = [c if c in alphabet and c != u"\n" else r"\%d;" % ord(c) for c in token]
return u"".join(ret) + "_"
def _unescape_token(token):
r"""Replaces escaped characters in the token with their unescaped versions.
Applies inverse transformations as _escape_token():
1. Replace "\u" with "_", and "\\" with "\".
2. Replace "\###;" with the unicode character the ### refers to.
Args:
token: escaped string
Returns:
unescaped string
"""
def match(m):
r"""Returns replacement string for matched object.
Matched objects contain one of the strings that matches the regex pattern:
r"\\u|\\\\|\\([0-9]+);"
The strings can be '\u', '\\', or '\###;' (### is any digit number).
m.group(0) refers to the entire matched string ('\u', '\\', or '\###;').
m.group(1) refers to the first parenthesized subgroup ('###').
m.group(0) exists for all match objects, while m.group(1) exists only for
the string '\###;'.
This function looks to see if m.group(1) exists. If it doesn't, then the
matched string must be '\u' or '\\' . In this case, the corresponding
replacement ('_' and '\') are returned. Note that in python, a single
backslash is written as '\\', and double backslash as '\\\\'.
If m.goup(1) exists, then use the integer in m.group(1) to return a
unicode character.
Args:
m: match object
Returns:
String to replace matched object with.
"""
# Check if the matched strings are '\u' or '\\'.
if m.group(1) is None:
return u"_" if m.group(0) == u"\\u" else u"\\"
# If m.group(1) exists, try and return unicode character.
try:
return six.unichr(int(m.group(1)))
except (ValueError, OverflowError) as _:
return _UNDEFINED_UNICODE
# Use match function to replace escaped substrings in the token.
return _UNESCAPE_REGEX.sub(match, token)
def _count_tokens(files,
file_byte_limit=1e6,
correct_strip=True,
master_char_set=None):
"""Return token counts of words in the files.
Samples file_byte_limit bytes from each file, and counts the words that appear
in the samples. The samples are semi-evenly distributed across the file.
Args:
files: List of filepaths
file_byte_limit: Max number of bytes that will be read from each file.
correct_strip: Whether to convert text to unicode before strip. This affects
vocabulary generation for PY2. Sets correct_strip to False in PY2 to
reproduce previous common public result. Sets correct_strip to True will
let PY2 and PY3 get a consistent vocabulary.
master_char_set: the char set.
Returns:
Dictionary mapping tokens to the number of times they appear in the sampled
lines from the files.
"""
if master_char_set is None:
master_char_set = _ALPHANUMERIC_CHAR_SET
token_counts = collections.defaultdict(int)
for filepath in files:
with tf.io.gfile.GFile(filepath, mode="r") as reader:
file_byte_budget = file_byte_limit
counter = 0
lines_to_skip = int(reader.size() / (file_byte_budget * 2))
for line in reader:
if counter < lines_to_skip:
counter += 1
else:
if file_byte_budget < 0:
break
if correct_strip:
line = native_to_unicode(line)
line = line.strip()
file_byte_budget -= len(line)
counter = 0
# Add words to token counts
for token in _split_string_to_tokens(
native_to_unicode(line), master_char_set):
token_counts[token] += 1
return token_counts
def _list_to_index_dict(lst):
"""Create dictionary mapping list items to their indices in the list."""
return {item: n for n, item in enumerate(lst)}
def _split_token_to_subtokens(token, subtoken_dict, max_subtoken_length):
"""Splits a token into subtokens defined in the subtoken dict."""
ret = []
start = 0
token_len = len(token)
while start < token_len:
# Find the longest subtoken, so iterate backwards.
for end in xrange(min(token_len, start + max_subtoken_length), start, -1):
subtoken = token[start:end]
if subtoken in subtoken_dict:
ret.append(subtoken)
start = end
break
else: # Did not break
# If there is no possible encoding of the escaped token then one of the
# characters in the token is not in the alphabet. This should be
# impossible and would be indicative of a bug.
raise ValueError("Was unable to split token \"%s\" into subtokens." %
token)
return ret
def _generate_subtokens_with_target_vocab_size(token_counts,
alphabet,
target_size,
threshold,
min_count=None,
reserved_tokens=None):
"""Generate subtoken vocabulary close to the target size."""
if reserved_tokens is None:
reserved_tokens = RESERVED_TOKENS
if min_count is not None:
logging.info("Using min_count=%d to generate vocab with target size %d",
min_count, target_size)
return _generate_subtokens(
token_counts, alphabet, min_count, reserved_tokens=reserved_tokens)
def bisect(min_val, max_val):
"""Recursive function to binary search for subtoken vocabulary."""
cur_count = (min_val + max_val) // 2
logging.info("Binary search: trying min_count=%d (%d %d)", cur_count,
min_val, max_val)
subtoken_list = _generate_subtokens(
token_counts, alphabet, cur_count, reserved_tokens=reserved_tokens)
val = len(subtoken_list)
logging.info("Binary search: min_count=%d resulted in %d tokens", cur_count,
val)
within_threshold = abs(val - target_size) < threshold
if within_threshold or min_val >= max_val or cur_count < 2:
return subtoken_list
if val > target_size:
other_subtoken_list = bisect(cur_count + 1, max_val)
else:
other_subtoken_list = bisect(min_val, cur_count - 1)
# Return vocabulary dictionary with the closest number of tokens.
other_val = len(other_subtoken_list)
if abs(other_val - target_size) < abs(val - target_size):
return other_subtoken_list
return subtoken_list
logging.info("Finding best min_count to get target size of %d", target_size)
return bisect(_MIN_MIN_COUNT, _MAX_MIN_COUNT)
def _generate_alphabet_dict(iterable, reserved_tokens=None):
"""Create set of characters that appear in any element in the iterable."""
if reserved_tokens is None:
reserved_tokens = RESERVED_TOKENS
alphabet = {c for token in iterable for c in token}
alphabet |= {c for token in reserved_tokens for c in token}
alphabet |= _ESCAPE_CHARS # Add escape characters to alphabet set.
return alphabet
def _count_and_gen_subtokens(token_counts, alphabet, subtoken_dict,
max_subtoken_length):
"""Count number of times subtokens appear, and generate new subtokens.
Args:
token_counts: dict mapping tokens to the number of times they appear in the
original files.
alphabet: list of allowed characters. Used to escape the tokens, which
guarantees that all tokens can be split into subtokens.
subtoken_dict: dict mapping subtokens to ids.
max_subtoken_length: maximum length of subtoken in subtoken_dict.
Returns:
A defaultdict mapping subtokens to the number of times they appear in the
tokens. The dict may contain new subtokens.
"""
subtoken_counts = collections.defaultdict(int)
for token, count in six.iteritems(token_counts):
token = _escape_token(token, alphabet)
subtokens = _split_token_to_subtokens(token, subtoken_dict,
max_subtoken_length)
# Generate new subtokens by taking substrings from token.
start = 0
for subtoken in subtokens:
for end in xrange(start + 1, len(token) + 1):
new_subtoken = token[start:end]
subtoken_counts[new_subtoken] += count
start += len(subtoken)
return subtoken_counts
def _filter_and_bucket_subtokens(subtoken_counts, min_count):
"""Return a bucketed list of subtokens that are filtered by count.
Args:
subtoken_counts: defaultdict mapping subtokens to their counts
min_count: int count used to filter subtokens
Returns:
List of subtoken sets, where subtokens in set i have the same length=i.
"""
# Create list of buckets, where subtokens in bucket i have length i.
subtoken_buckets = []
for subtoken, count in six.iteritems(subtoken_counts):
if count < min_count: # Filter out subtokens that don't appear enough
continue
while len(subtoken_buckets) <= len(subtoken):
subtoken_buckets.append(set())
subtoken_buckets[len(subtoken)].add(subtoken)
return subtoken_buckets
def _gen_new_subtoken_list(subtoken_counts,
min_count,
alphabet,
reserved_tokens=None):
"""Generate candidate subtokens ordered by count, and new max subtoken length.
Add subtokens to the candiate list in order of length (longest subtokens
first). When a subtoken is added, the counts of each of its prefixes are
decreased. Prefixes that don't appear much outside the subtoken are not added
to the candidate list.
For example:
subtoken being added to candidate list: 'translate'
subtoken_counts: {'translate':10, 't':40, 'tr':16, 'tra':12, ...}
min_count: 5
When 'translate' is added, subtoken_counts is updated to:
{'translate':0, 't':30, 'tr':6, 'tra': 2, ...}
The subtoken 'tra' will not be added to the candidate list, because it appears
twice (less than min_count) outside of 'translate'.
Args:
subtoken_counts: defaultdict mapping str subtokens to int counts
min_count: int minumum count requirement for subtokens
alphabet: set of characters. Each character is added to the subtoken list to
guarantee that all tokens can be encoded.
reserved_tokens: list of tokens that will be added to the beginning of the
returned subtoken list.
Returns:
List of candidate subtokens in decreasing count order, and maximum subtoken
length
"""
if reserved_tokens is None:
reserved_tokens = RESERVED_TOKENS
# Create a list of (count, subtoken) for each candidate subtoken.
subtoken_candidates = []
# Use bucketted list to iterate through subtokens in order of length.
# subtoken_buckets[i] = set(subtokens), where each subtoken has length i.
subtoken_buckets = _filter_and_bucket_subtokens(subtoken_counts, min_count)
max_subtoken_length = len(subtoken_buckets) - 1
# Go through the list in reverse order to consider longer subtokens first.
for subtoken_len in xrange(max_subtoken_length, 0, -1):
for subtoken in subtoken_buckets[subtoken_len]:
count = subtoken_counts[subtoken]
# Possible if this subtoken is a prefix of another token.
if count < min_count:
continue
# Ignore alphabet/reserved tokens, which will be added manually later.
if subtoken not in alphabet and subtoken not in reserved_tokens:
subtoken_candidates.append((count, subtoken))
# Decrement count of the subtoken's prefixes (if a longer subtoken is
# added, its prefixes lose priority to be added).
for end in xrange(1, subtoken_len):
subtoken_counts[subtoken[:end]] -= count
# Add alphabet subtokens (guarantees that all strings are encodable).
subtoken_candidates.extend((subtoken_counts.get(a, 0), a) for a in alphabet)
# Order subtoken candidates by decreasing count.
subtoken_list = [t for _, t in sorted(subtoken_candidates, reverse=True)]
# Add reserved tokens to beginning of the list.
subtoken_list = reserved_tokens + subtoken_list
return subtoken_list, max_subtoken_length
def _generate_subtokens(token_counts,
alphabet,
min_count,
num_iterations=4,
reserved_tokens=None):
"""Create a list of subtokens in decreasing order of frequency.
Args:
token_counts: dict mapping str tokens -> int count
alphabet: set of characters
min_count: int minimum number of times a subtoken must appear before it is
added to the vocabulary.
num_iterations: int number of iterations to generate new tokens.
reserved_tokens: list of tokens that will be added to the beginning to the
returned subtoken list.
Returns:
Sorted list of subtokens (most frequent first)
"""
if reserved_tokens is None:
reserved_tokens = RESERVED_TOKENS
# Use alphabet set to create initial list of subtokens
subtoken_list = reserved_tokens + list(alphabet)
max_subtoken_length = 1
# On each iteration, segment all words using the subtokens defined in
# subtoken_dict, count how often the resulting subtokens appear, and update
# the dictionary with subtokens w/ high enough counts.
for i in xrange(num_iterations):
logging.info("\tGenerating subtokens: iteration %d", i)
# Generate new subtoken->id dictionary using the new subtoken list.
subtoken_dict = _list_to_index_dict(subtoken_list)
# Create dict mapping subtoken->count, with additional subtokens created
# from substrings taken from the tokens.
subtoken_counts = _count_and_gen_subtokens(token_counts, alphabet,
subtoken_dict,
max_subtoken_length)
# Generate new list of subtokens sorted by subtoken count.
subtoken_list, max_subtoken_length = _gen_new_subtoken_list(
subtoken_counts, min_count, alphabet, reserved_tokens)
logging.info("\tVocab size: %d", len(subtoken_list))
return subtoken_list
official/nlp/transformer/utils/tokenizer_test.py deleted 100644 → 0
View file @ d78ec6ea
# Copyright 2021 The TensorFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Test Subtokenizer and string helper methods."""
import collections
import tempfile
import tensorflow as tf
from official.nlp.transformer.utils import tokenizer
class SubtokenizerTest(tf.test.TestCase):
def _init_subtokenizer(self, vocab_list):
temp_file = tempfile.NamedTemporaryFile(delete=False)
with tf.io.gfile.GFile(temp_file.name, "w") as w:
for subtoken in vocab_list:
w.write("'%s'" % subtoken)
w.write("\n")
return tokenizer.Subtokenizer(temp_file.name, reserved_tokens=[])
def test_encode(self):
vocab_list = ["123_", "test", "ing_"]
subtokenizer = self._init_subtokenizer(vocab_list)
s = "testing 123"
encoded_list = subtokenizer.encode(s)
self.assertEqual([1, 2, 0], encoded_list)
def test_decode(self):
vocab_list = ["123_", "test", "ing_"]
subtokenizer = self._init_subtokenizer(vocab_list)
encoded_list = [1, 2, 0] # testing 123
decoded_str = subtokenizer.decode(encoded_list)
self.assertEqual("testing 123", decoded_str)
def test_subtoken_ids_to_tokens(self):
vocab_list = ["123_", "test", "ing_"]
subtokenizer = self._init_subtokenizer(vocab_list)
encoded_list = [1, 2, 0] # testing 123
token_list = subtokenizer._subtoken_ids_to_tokens(encoded_list)
self.assertEqual([u"testing", u"123"], token_list)
class StringHelperTest(tf.test.TestCase):
def test_split_string_to_tokens(self):
text = "test? testing 123."
tokens = tokenizer._split_string_to_tokens(text,
tokenizer._ALPHANUMERIC_CHAR_SET)
self.assertEqual(["test", "? ", "testing", "123", "."], tokens)
def test_join_tokens_to_string(self):
tokens = ["test", "? ", "testing", "123", "."]
s = tokenizer._join_tokens_to_string(tokens,
tokenizer._ALPHANUMERIC_CHAR_SET)
self.assertEqual("test? testing 123.", s)
def test_escape_token(self):
token = u"abc_\\4"
alphabet = set("abc_\\u;")
escaped_token = tokenizer._escape_token(token, alphabet)
self.assertEqual("abc\\u\\\\\\52;_", escaped_token)
def test_unescape_token(self):
escaped_token = u"Underline: \\u, Backslash: \\\\, Unicode: \\52;"
unescaped_token = tokenizer._unescape_token(escaped_token)
self.assertEqual("Underline: _, Backslash: \\, Unicode: 4", unescaped_token)
def test_list_to_index_dict(self):
lst = ["test", "strings"]
d = tokenizer._list_to_index_dict(lst)
self.assertDictEqual({"test": 0, "strings": 1}, d)
def test_split_token_to_subtokens(self):
token = "abc"
subtoken_dict = {"a": 0, "b": 1, "c": 2, "ab": 3}
max_subtoken_length = 2
subtokens = tokenizer._split_token_to_subtokens(token, subtoken_dict,
max_subtoken_length)
self.assertEqual(["ab", "c"], subtokens)
def test_generate_alphabet_dict(self):
s = ["testing", "123"]
reserved_tokens = ["???"]
alphabet = tokenizer._generate_alphabet_dict(s, reserved_tokens)
self.assertIn("?", alphabet)
self.assertIn("t", alphabet)
self.assertIn("e", alphabet)
self.assertIn("s", alphabet)
self.assertIn("i", alphabet)
self.assertIn("n", alphabet)
self.assertIn("g", alphabet)
self.assertIn("1", alphabet)
self.assertIn("2", alphabet)
self.assertIn("3", alphabet)
def test_count_and_gen_subtokens(self):
token_counts = {"abc": 5}
alphabet = set("abc_")
subtoken_dict = {"a": 0, "b": 1, "c": 2, "_": 3}
max_subtoken_length = 2
subtoken_counts = tokenizer._count_and_gen_subtokens(
token_counts, alphabet, subtoken_dict, max_subtoken_length)
self.assertIsInstance(subtoken_counts, collections.defaultdict)
self.assertDictEqual(
{
"a": 5,
"b": 5,
"c": 5,
"_": 5,
"ab": 5,
"bc": 5,
"c_": 5,
"abc": 5,
"bc_": 5,
"abc_": 5
}, subtoken_counts)
def test_filter_and_bucket_subtokens(self):
subtoken_counts = collections.defaultdict(int, {
"a": 2,
"b": 4,
"c": 1,
"ab": 6,
"ac": 3,
"abbc": 5
})
min_count = 3
subtoken_buckets = tokenizer._filter_and_bucket_subtokens(
subtoken_counts, min_count)
self.assertEqual(len(subtoken_buckets[0]), 0)
self.assertEqual(set("b"), subtoken_buckets[1])
self.assertEqual(set(["ab", "ac"]), subtoken_buckets[2])
self.assertEqual(len(subtoken_buckets[3]), 0)
self.assertEqual(set(["abbc"]), subtoken_buckets[4])
def test_gen_new_subtoken_list(self):
subtoken_counts = collections.defaultdict(int, {
"translate": 10,
"t": 40,
"tr": 16,
"tra": 12
})
min_count = 5
alphabet = set("translate")
reserved_tokens = ["reserved", "tokens"]
subtoken_list, max_token_length = tokenizer._gen_new_subtoken_list(
subtoken_counts, min_count, alphabet, reserved_tokens)
# Check that "tra" isn"t in the list (its count should be decremented to 2,
# so it should not be added to the canddiate list).
self.assertNotIn("tra", subtoken_list)
self.assertIn("tr", subtoken_list)
self.assertIn("t", subtoken_list)
self.assertEqual(len("translate"), max_token_length)
def test_generate_subtokens(self):
token_counts = {"ab": 1, "bc": 3, "abc": 5}
alphabet = set("abc_")
min_count = 100
num_iterations = 1
reserved_tokens = ["reserved", "tokens"]
vocab_list = tokenizer._generate_subtokens(token_counts, alphabet,
min_count, num_iterations,
reserved_tokens)
# Check that reserved tokens are at the front of the list
self.assertEqual(vocab_list[:2], reserved_tokens)
# Check that each character in alphabet is in the vocab list
for c in alphabet:
self.assertIn(c, vocab_list)
if __name__ == "__main__":
tf.test.main()
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