def _load(path, vocab, normalize=False) -> Tuple[Vocab, Union[np.ndarray, None]]:
if not vocab:
vocab = Vocab()
if not path:
return vocab, None
assert vocab.unk_idx is not None
word2vec, dim = load_word2vec(path)
for word in word2vec:
vocab.get_idx(word)
pret_embs = np.zeros(shape=(len(vocab), dim), dtype=np.float32)
state = np.random.get_state()
np.random.seed(0)
bias = np.random.uniform(low=-0.001, high=0.001, size=dim).astype(dtype=np.float32)
scale = np.sqrt(3.0 / dim)
for word, idx in vocab.token_to_idx.items():
vec = word2vec.get(word, None)
if vec is None:
vec = word2vec.get(word.lower(), None)
# if vec is not None:
# vec += bias
if vec is None:
# vec = np.random.uniform(-scale, scale, [dim])
vec = np.zeros([dim], dtype=np.float32)
pret_embs[idx] = vec
# noinspection PyTypeChecker
np.random.set_state(state)
return vocab, pret_embs
def index_word2vec_with_vocab(filepath: str,
vocab: Vocab,
extend_vocab=True,
unk=None,
lowercase=False,
init='uniform',
normalize=None) -> torch.Tensor:
"""
Args:
filepath: The path to pretrained embedding.
vocab: The vocabulary from training set.
extend_vocab: Unlock vocabulary of training set to add those tokens in pretrained embedding file.
unk: UNK token.
lowercase: Convert words in pretrained embeddings into lowercase.
init: Indicate which initialization to use for oov tokens.
normalize: ``True`` or a method to normalize the embedding matrix.
Returns:
An embedding matrix.
"""
pret_vocab, pret_matrix = load_word2vec_as_vocab_tensor(filepath)
if unk and unk in pret_vocab:
pret_vocab[vocab.safe_unk_token] = pret_vocab.pop(unk)
if extend_vocab:
vocab.unlock()
for word in pret_vocab:
vocab.get_idx(word.lower() if lowercase else word)
vocab.lock()
ids = []
unk_id_offset = 0
for word, idx in vocab.token_to_idx.items():
word_id = pret_vocab.get(word, None)
# Retry lower case
if word_id is None:
word_id = pret_vocab.get(word.lower(), None)
if word_id is None:
word_id = len(pret_vocab) + unk_id_offset
unk_id_offset += 1
ids.append(word_id)
if unk_id_offset:
unk_embeds = torch.zeros(unk_id_offset, pret_matrix.size(1))
if init and init != 'zeros':
if init == 'uniform':
init = embedding_uniform
else:
raise ValueError(f'Unsupported init {init}')
unk_embeds = init(unk_embeds)
pret_matrix = torch.cat([pret_matrix, unk_embeds])
ids = torch.LongTensor(ids)
embedding = pret_matrix.index_select(0, ids)
if normalize == 'norm':
embedding /= (torch.norm(embedding, dim=1, keepdim=True) + 1e-12)
elif normalize == 'std':
embedding /= torch.std(embedding)
return embedding
def __init__(self, filepath: str = None, vocab: Vocab = None, expand_vocab=True, lowercase=True,
input_dim=None, output_dim=None, unk=None, normalize=False,
embeddings_initializer='VarianceScaling',
embeddings_regularizer=None,
activity_regularizer=None, embeddings_constraint=None, mask_zero=True, input_length=None,
name=None, **kwargs):
filepath = get_resource(filepath)
word2vec, _output_dim = load_word2vec(filepath)
if output_dim:
assert output_dim == _output_dim, f'output_dim = {output_dim} does not match {filepath}'
output_dim = _output_dim
# if the `unk` token exists in the pretrained,
# then replace it with a self-defined one, usually the one in word vocab
if unk and unk in word2vec:
word2vec[vocab.safe_unk_token] = word2vec.pop(unk)
if vocab is None:
vocab = Vocab()
vocab.update(word2vec.keys())
if expand_vocab and vocab.mutable:
for word in word2vec:
vocab.get_idx(word.lower() if lowercase else word)
if input_dim:
assert input_dim == len(vocab), f'input_dim = {input_dim} does not match {filepath}'
input_dim = len(vocab)
# init matrix
self._embeddings_initializer = embeddings_initializer
embeddings_initializer = tf.keras.initializers.get(embeddings_initializer)
with tf.device('cpu:0'):
pret_embs = embeddings_initializer(shape=[input_dim, output_dim]).numpy()
# insert to pret_embs
for word, idx in vocab.token_to_idx.items():
vec = word2vec.get(word, None)
# Retry lower case
if vec is None and lowercase:
vec = word2vec.get(word.lower(), None)
if vec is not None:
pret_embs[idx] = vec
if normalize:
pret_embs /= np.std(pret_embs)
if not name:
name = os.path.splitext(os.path.basename(filepath))[0]
super().__init__(input_dim, output_dim, tf.keras.initializers.Constant(pret_embs), embeddings_regularizer,
activity_regularizer, embeddings_constraint, mask_zero, input_length, name=name, **kwargs)
self.filepath = filepath
self.expand_vocab = expand_vocab
self.lowercase = lowercase
