💫 Feature/improve pretraining (#2971)

* Improve spacy pretrain script

* Implement BERT-style 'masked language model' objective. Much better
results.

* Improve logging.

* Add length cap for documents, to avoid memory errors.

* Require thinc 7.0.0.dev1

* Require thinc 7.0.0.dev1

* Add argument for using pretrained vectors

* Fix defaults

* Fix syntax error

* Improve spacy pretrain script

* Implement BERT-style 'masked language model' objective. Much better
results.

* Improve logging.

* Add length cap for documents, to avoid memory errors.

* Require thinc 7.0.0.dev1

* Require thinc 7.0.0.dev1

* Add argument for using pretrained vectors

* Fix defaults

* Fix syntax error

* Tweak pretraining script

* Fix data limits in spacy.gold

* Fix pretrain script
This commit is contained in:
Matthew Honnibal 2018-11-28 18:04:58 +01:00 committed by GitHub
parent 0fdb25b958
commit 61e435610e
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4 changed files with 123 additions and 22 deletions

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@ -2,7 +2,7 @@ cython>=0.25
numpy>=1.15.0
cymem>=2.0.2,<2.1.0
preshed>=2.0.1,<2.1.0
thinc==7.0.0.dev0
thinc==7.0.0.dev1
blis>=0.2.2,<0.3.0
murmurhash>=0.28.0,<1.1.0
cytoolz>=0.9.0,<0.10.0

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@ -200,7 +200,7 @@ def setup_package():
"murmurhash>=0.28.0,<1.1.0",
"cymem>=2.0.2,<2.1.0",
"preshed>=2.0.1,<2.1.0",
"thinc==7.0.0.dev0",
"thinc==7.0.0.dev1",
"blis>=0.2.2,<0.3.0",
"plac<1.0.0,>=0.9.6",
"ujson>=1.35",

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@ -24,10 +24,12 @@ import sys
from collections import Counter
import spacy
from spacy.attrs import ID
from spacy.tokens import Doc
from spacy.attrs import ID, HEAD
from spacy.util import minibatch, minibatch_by_words, use_gpu, compounding, ensure_path
from spacy._ml import Tok2Vec, flatten, chain, zero_init, create_default_optimizer
from thinc.v2v import Affine
from thinc.api import wrap
def prefer_gpu():
@ -47,13 +49,14 @@ def load_texts(path):
'''
path = ensure_path(path)
with path.open('r', encoding='utf8') as file_:
texts = [json.loads(line)['text'] for line in file_]
texts = [json.loads(line) for line in file_]
random.shuffle(texts)
return texts
def stream_texts():
for line in sys.stdin:
yield json.loads(line)['text']
yield json.loads(line)
def make_update(model, docs, optimizer, drop=0.):
@ -65,11 +68,33 @@ def make_update(model, docs, optimizer, drop=0.):
RETURNS loss: A float for the loss.
"""
predictions, backprop = model.begin_update(docs, drop=drop)
loss, gradients = get_vectors_loss(model.ops, docs, predictions)
gradients = get_vectors_loss(model.ops, docs, predictions)
backprop(gradients, sgd=optimizer)
# Don't want to return a cupy object here
# The gradients are modified in-place by the BERT MLM,
# so we get an accurate loss
loss = float((gradients**2).mean())
return loss
def make_docs(nlp, batch):
docs = []
for record in batch:
text = record["text"]
if "tokens" in record:
doc = Doc(nlp.vocab, words=record["tokens"])
else:
doc = nlp.make_doc(text)
if "heads" in record:
heads = record["heads"]
heads = numpy.asarray(heads, dtype="uint64")
heads = heads.reshape((len(doc), 1))
doc = doc.from_array([HEAD], heads)
if len(doc) >= 1 and len(doc) < 200:
docs.append(doc)
return docs
def get_vectors_loss(ops, docs, prediction):
"""Compute a mean-squared error loss between the documents' vectors and
the prediction.
@ -84,10 +109,8 @@ def get_vectors_loss(ops, docs, prediction):
# and look them up all at once. This prevents data copying.
ids = ops.flatten([doc.to_array(ID).ravel() for doc in docs])
target = docs[0].vocab.vectors.data[ids]
d_scores = (prediction - target) / prediction.shape[0]
# Don't want to return a cupy object here
loss = float((d_scores**2).sum())
return loss, d_scores
d_scores = prediction - target
return d_scores
def create_pretraining_model(nlp, tok2vec):
@ -107,15 +130,77 @@ def create_pretraining_model(nlp, tok2vec):
tok2vec,
output_layer
)
model = masked_language_model(nlp.vocab, model)
model.tok2vec = tok2vec
model.output_layer = output_layer
model.begin_training([nlp.make_doc('Give it a doc to infer shapes')])
return model
def masked_language_model(vocab, model, mask_prob=0.15):
'''Convert a model into a BERT-style masked language model'''
vocab_words = [lex.text for lex in vocab if lex.prob != 0.0]
vocab_probs = [lex.prob for lex in vocab if lex.prob != 0.0]
vocab_words = vocab_words[:10000]
vocab_probs = vocab_probs[:10000]
vocab_probs = numpy.exp(numpy.array(vocab_probs, dtype='f'))
vocab_probs /= vocab_probs.sum()
def mlm_forward(docs, drop=0.):
mask, docs = apply_mask(docs, vocab_words, vocab_probs,
mask_prob=mask_prob)
mask = model.ops.asarray(mask).reshape((mask.shape[0], 1))
output, backprop = model.begin_update(docs, drop=drop)
def mlm_backward(d_output, sgd=None):
d_output *= 1-mask
return backprop(d_output, sgd=sgd)
return output, mlm_backward
return wrap(mlm_forward, model)
def apply_mask(docs, vocab_texts, vocab_probs, mask_prob=0.15):
N = sum(len(doc) for doc in docs)
mask = numpy.random.uniform(0., 1.0, (N,))
mask = mask >= mask_prob
i = 0
masked_docs = []
for doc in docs:
words = []
for token in doc:
if not mask[i]:
word = replace_word(token.text, vocab_texts, vocab_probs)
else:
word = token.text
words.append(word)
i += 1
spaces = [bool(w.whitespace_) for w in doc]
# NB: If you change this implementation to instead modify
# the docs in place, take care that the IDs reflect the original
# words. Currently we use the original docs to make the vectors
# for the target, so we don't lose the original tokens. But if
# you modified the docs in place here, you would.
masked_docs.append(Doc(doc.vocab, words=words, spaces=spaces))
return mask, masked_docs
def replace_word(word, vocab_texts, vocab_probs, mask='[MASK]'):
roll = random.random()
if roll < 0.8:
return mask
elif roll < 0.9:
index = numpy.random.choice(len(vocab_texts), p=vocab_probs)
return vocab_texts[index]
else:
return word
class ProgressTracker(object):
def __init__(self, frequency=100000):
self.loss = 0.
self.loss = 0.0
self.prev_loss = 0.0
self.nr_word = 0
self.words_per_epoch = Counter()
self.frequency = frequency
@ -132,7 +217,15 @@ class ProgressTracker(object):
wps = words_since_update / (time.time() - self.last_time)
self.last_update = self.nr_word
self.last_time = time.time()
status = (epoch, self.nr_word, '%.5f' % self.loss, int(wps))
loss_per_word = self.loss - self.prev_loss
status = (
epoch,
self.nr_word,
"%.5f" % self.loss,
"%.4f" % loss_per_word,
int(wps),
)
self.prev_loss = float(self.loss)
return status
else:
return None
@ -145,12 +238,13 @@ class ProgressTracker(object):
width=("Width of CNN layers", "option", "cw", int),
depth=("Depth of CNN layers", "option", "cd", int),
embed_rows=("Embedding rows", "option", "er", int),
use_vectors=("Whether to use the static vectors as input features", "flag", "uv"),
dropout=("Dropout", "option", "d", float),
seed=("Seed for random number generators", "option", "s", float),
nr_iter=("Number of iterations to pretrain", "option", "i", int),
)
def pretrain(texts_loc, vectors_model, output_dir, width=128, depth=4,
embed_rows=1000, dropout=0.2, nr_iter=10, seed=0):
embed_rows=5000, use_vectors=False, dropout=0.2, nr_iter=100, seed=0):
"""
Pre-train the 'token-to-vector' (tok2vec) layer of pipeline components,
using an approximate language-modelling objective. Specifically, we load
@ -175,11 +269,13 @@ def pretrain(texts_loc, vectors_model, output_dir, width=128, depth=4,
with (output_dir / 'config.json').open('w') as file_:
file_.write(json.dumps(config))
has_gpu = prefer_gpu()
print("Use GPU?", has_gpu)
nlp = spacy.load(vectors_model)
pretrained_vectors = None if not use_vectors else nlp.vocab.vectors.name
model = create_pretraining_model(nlp,
Tok2Vec(width, embed_rows,
conv_depth=depth,
pretrained_vectors=nlp.vocab.vectors.name,
pretrained_vectors=pretrained_vectors,
bilstm_depth=0, # Requires PyTorch. Experimental.
cnn_maxout_pieces=2, # You can try setting this higher
subword_features=True)) # Set to False for character models, e.g. Chinese
@ -188,19 +284,19 @@ def pretrain(texts_loc, vectors_model, output_dir, width=128, depth=4,
print('Epoch', '#Words', 'Loss', 'w/s')
texts = stream_texts() if texts_loc == '-' else load_texts(texts_loc)
for epoch in range(nr_iter):
for batch in minibatch(texts, size=64):
docs = [nlp.make_doc(text) for text in batch]
for batch in minibatch(texts, size=256):
docs = make_docs(nlp, batch)
loss = make_update(model, docs, optimizer, drop=dropout)
progress = tracker.update(epoch, loss, docs)
if progress:
print(*progress)
if texts_loc == '-' and tracker.words_per_epoch[epoch] >= 10**6:
if texts_loc == '-' and tracker.words_per_epoch[epoch] >= 10**7:
break
with model.use_params(optimizer.averages):
with (output_dir / ('model%d.bin' % epoch)).open('wb') as file_:
file_.write(model.tok2vec.to_bytes())
with (output_dir / 'log.jsonl').open('a') as file_:
file_.write(json.dumps({'nr_word': tracker.nr_word,
'loss': tracker.loss, 'epoch': epoch}))
'loss': tracker.loss, 'epoch': epoch}) + '\n')
if texts_loc != '-':
texts = load_texts(texts_loc)

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@ -25,6 +25,7 @@ from .compat import json_dumps
from libc.stdio cimport FILE, fopen, fclose, fread, fwrite, feof, fseek
def tags_to_entities(tags):
entities = []
start = None
@ -110,19 +111,23 @@ class GoldCorpus(object):
# Write temp directory with one doc per file, so we can shuffle
# and stream
self.tmp_dir = Path(tempfile.mkdtemp())
self.write_msgpack(self.tmp_dir / 'train', train)
self.write_msgpack(self.tmp_dir / 'dev', dev)
self.write_msgpack(self.tmp_dir / 'train', train, limit=self.limit)
self.write_msgpack(self.tmp_dir / 'dev', dev, limit=self.limit)
def __del__(self):
shutil.rmtree(self.tmp_dir)
@staticmethod
def write_msgpack(directory, doc_tuples):
def write_msgpack(directory, doc_tuples, limit=0):
if not directory.exists():
directory.mkdir()
n = 0
for i, doc_tuple in enumerate(doc_tuples):
with open(directory / '{}.msg'.format(i), 'wb') as file_:
msgpack.dump([doc_tuple], file_, use_bin_type=True)
n += len(doc_tuple[1])
if limit and n >= limit:
break
@staticmethod
def walk_corpus(path):
@ -350,7 +355,7 @@ def _json_iterate(loc):
py_str = py_raw[start : i+1].decode('utf8')
try:
yield json.loads(py_str)
except:
except Exception:
print(py_str)
raise
start = -1