class FeatureExtractor(object):
def __init__(self, model, options, vocab, nnvecs=1):
self.word_counts, words, chars, pos, cpos, rels, treebanks, langs = vocab
self.model = model
self.nnvecs = nnvecs
# Load ELMo if the option is set
if options.elmo is not None:
from elmo import ELMo
self.elmo = ELMo(options.elmo, options.elmo_gamma,
options.elmo_learn_gamma)
self.elmo.init_weights(model)
else:
self.elmo = None
extra_words = 2 # MLP padding vector and OOV vector
self.words = {word: ind for ind, word in enumerate(words, extra_words)}
self.word_lookup = self.model.add_lookup_parameters(
(len(self.words) + extra_words, options.word_emb_size))
extra_pos = 2 # MLP padding vector and OOV vector
self.pos = {pos: ind for ind, pos in enumerate(cpos, extra_pos)}
self.pos_lookup = self.model.add_lookup_parameters(
(len(cpos) + extra_pos, options.pos_emb_size))
self.irels = rels
self.rels = {rel: ind for ind, rel in enumerate(rels)}
extra_chars = 1 # OOV vector
self.chars = {char: ind for ind, char in enumerate(chars, extra_chars)}
self.char_lookup = self.model.add_lookup_parameters(
(len(chars) + extra_chars, options.char_emb_size))
extra_treebanks = 1 # Padding vector
self.treebanks = {
treebank: ind
for ind, treebank in enumerate(treebanks, extra_treebanks)
}
self.treebank_lookup = self.model.add_lookup_parameters(
(len(treebanks) + extra_treebanks, options.tbank_emb_size))
# initialise word vectors with external embeddings where they exist
# This part got ugly - TODO: refactor
if not options.predict:
self.external_embedding = defaultdict(lambda: {})
if options.ext_word_emb_file and options.word_emb_size > 0:
# Load pre-trained word embeddings
for lang in langs:
embeddings = utils.get_external_embeddings(
options,
emb_file=options.ext_word_emb_file,
lang=lang,
words=self.words.viewkeys())
self.external_embedding["words"].update(embeddings)
if options.ext_char_emb_file and options.char_emb_size > 0:
# Load pre-trained character embeddings
for lang in langs:
embeddings = utils.get_external_embeddings(
options,
emb_file=options.ext_char_emb_file,
lang=lang,
words=self.chars,
chars=True)
self.external_embedding["chars"].update(embeddings)
if options.ext_emb_dir:
# For every language, load the data for the word and character
# embeddings from a directory.
for lang in langs:
if options.word_emb_size > 0:
embeddings = utils.get_external_embeddings(
options,
emb_dir=options.ext_emb_dir,
lang=lang,
words=self.words.viewkeys())
self.external_embedding["words"].update(embeddings)
if options.char_emb_size > 0:
embeddings = utils.get_external_embeddings(
options,
emb_dir=options.ext_emb_dir,
lang=lang,
words=self.chars,
chars=True)
self.external_embedding["chars"].update(embeddings)
self.init_lookups(options)
elmo_emb_size = self.elmo.emb_dim if self.elmo else 0
self.lstm_input_size = (
options.word_emb_size + elmo_emb_size + options.pos_emb_size +
options.tbank_emb_size + 2 *
(options.char_lstm_output_size if options.char_emb_size > 0 else 0)
)
print "Word-level LSTM input size: " + str(self.lstm_input_size)
self.bilstms = []
if options.no_bilstms > 0:
self.bilstms.append(
BiLSTM(self.lstm_input_size,
options.lstm_output_size,
self.model,
dropout_rate=0.33))
for i in range(1, options.no_bilstms):
self.bilstms.append(
BiLSTM(2 * options.lstm_output_size,
options.lstm_output_size,
self.model,
dropout_rate=0.33))
#used in the PaddingVec
self.word2lstm = self.model.add_parameters(
(options.lstm_output_size * 2, self.lstm_input_size))
self.word2lstmbias = self.model.add_parameters(
(options.lstm_output_size * 2))
else:
self.word2lstm = self.model.add_parameters(
(self.lstm_input_size, self.lstm_input_size))
self.word2lstmbias = self.model.add_parameters(
(self.lstm_input_size))
self.char_bilstm = BiLSTM(options.char_emb_size,
options.char_lstm_output_size,
self.model,
dropout_rate=0.33)
self.charPadding = self.model.add_parameters(
(options.char_lstm_output_size * 2))
def Init(self, options):
paddingWordVec = self.word_lookup[
1] if options.word_emb_size > 0 else None
paddingElmoVec = dy.zeros(self.elmo.emb_dim) if self.elmo else None
paddingPosVec = self.pos_lookup[1] if options.pos_emb_size > 0 else None
paddingCharVec = self.charPadding.expr(
) if options.char_emb_size > 0 else None
paddingTbankVec = self.treebank_lookup[
0] if options.tbank_emb_size > 0 else None
self.paddingVec = dy.tanh(self.word2lstm.expr() *\
dy.concatenate(filter(None,[paddingWordVec,
paddingElmoVec,
paddingPosVec,
paddingCharVec,
paddingTbankVec])) + self.word2lstmbias.expr())
self.empty = self.paddingVec if self.nnvecs == 1 else\
dy.concatenate([self.paddingVec for _ in xrange(self.nnvecs)])
def getWordEmbeddings(self,
sentence,
train,
options,
test_embeddings=defaultdict(lambda: {})):
if self.elmo:
# Get full text of sentence - excluding root, which is loaded differently
# for transition and graph-based parsers.
if options.graph_based:
sentence_text = " ".join(
[entry.form for entry in sentence[1:]])
else:
sentence_text = " ".join(
[entry.form for entry in sentence[:-1]])
elmo_sentence_representation = \
self.elmo.get_sentence_representation(sentence_text)
for i, root in enumerate(sentence):
root.vecs = defaultdict(
lambda: None
) # all vecs are None by default (possibly a little risky?)
if options.word_emb_size > 0:
if train:
word_count = float(self.word_counts.get(root.norm, 0))
dropFlag = random.random() > word_count / (0.25 +
word_count)
root.vecs["word"] = self.word_lookup[
self.words.get(root.norm, 0) if not dropFlag else 0]
else: # need to check in test_embeddings at prediction time
if root.norm in self.words:
root.vecs["word"] = self.word_lookup[self.words[
root.norm]]
elif root.norm in test_embeddings["words"]:
root.vecs["word"] = dy.inputVector(
test_embeddings["words"][root.norm])
else:
root.vecs["word"] = self.word_lookup[0]
if options.pos_emb_size > 0:
root.vecs["pos"] = self.pos_lookup[self.pos.get(root.cpos, 0)]
if options.char_emb_size > 0:
root.vecs["char"] = self.get_char_vector(
root, train, test_embeddings["chars"])
if options.tbank_emb_size > 0:
if options.forced_tbank_emb:
treebank_id = options.forced_tbank_emb
elif root.proxy_tbank:
treebank_id = root.proxy_tbank
else:
treebank_id = root.treebank_id
# this is a bit of a hack for models trained on an old version of the code
# that used treebank name rather than id as the lookup
if not treebank_id in self.treebanks and treebank_id in utils.reverse_iso_dict and \
utils.reverse_iso_dict[treebank_id] in self.treebanks:
treebank_id = utils.reverse_iso_dict[treebank_id]
root.vecs["treebank"] = self.treebank_lookup[
self.treebanks[treebank_id]]
if self.elmo:
if i < len(sentence) - 1:
# Don't look up the 'root' word
root.vecs["elmo"] = elmo_sentence_representation[i]
else:
# TODO
root.vecs["elmo"] = dy.zeros(self.elmo.emb_dim)
root.vec = dy.concatenate(
filter(None, [
root.vecs["word"], root.vecs["elmo"], root.vecs["pos"],
root.vecs["char"], root.vecs["treebank"]
]))
for bilstm in self.bilstms:
bilstm.set_token_vecs(sentence, train)
def get_char_vector(self, root, train, test_embeddings_chars={}):
if root.char_rep == "*root*": # no point running a character analysis over this placeholder token
return self.charPadding.expr(
) # use the padding vector if it's the root token
else:
char_vecs = []
for char in root.char_rep:
if char in self.chars:
char_vecs.append(self.char_lookup[self.chars[char]])
elif char in test_embeddings_chars:
char_vecs.append(
dy.inputVector(test_embeddings_chars[char]))
else:
char_vecs.append(self.char_lookup[0])
return self.char_bilstm.get_sequence_vector(char_vecs, train)
def init_lookups(self, options):
if self.external_embedding["words"]:
print 'Initialising %i word vectors with external embeddings' % len(
self.external_embedding["words"])
for word in self.external_embedding["words"]:
if len(self.external_embedding["words"]
[word]) != options.word_emb_size:
raise Exception(
"Size of external embedding does not match specified word embedding size of %s"
% (options.word_emb_size))
self.word_lookup.init_row(
self.words[word], self.external_embedding["words"][word])
elif options.word_emb_size > 0:
print 'No word external embeddings found: all vectors initialised randomly'
if self.external_embedding["chars"]:
print 'Initialising %i char vectors with external embeddings' % len(
self.external_embedding["chars"])
for char in self.external_embedding["chars"]:
if len(self.external_embedding["chars"]
[char]) != options.char_emb_size:
raise Exception(
"Size of external embedding does not match specified char embedding size of %s"
% (options.char_emb_size))
self.char_lookup.init_row(
self.chars[char], self.external_embedding["chars"][char])
elif options.char_emb_size > 0:
print 'No character external embeddings found: all vectors initialised randomly'
VOCAB_DIM = len(field_char.vocab)
OUTPUT_DIM = len(field_word.vocab)
# OTHER HYPER-PARAMETERS
BATCH_SIZE = 32
N_EPOCHS = 100
CLIP = 1
best_valid_loss = float('inf')
# PAD_IDX = field_word.vocab.stoi["<pad>"] # PAD token for word, NOT CHAR
model = ELMo(VOCAB_DIM, OUTPUT_DIM, CHAR_EMB_DIM, HID_DIM, PRJ_DIM, FILTERS,
CHAR_LEN, N_LAYERS).to(DEVICE)
# Initialize
model.init_weights()
print(f'The model has {count_parameters(model):,} trainable parameters')
import time
# criterion = cal_loss
criterion = nn.CrossEntropyLoss()
optimizer = optim.Adam(model.parameters())
train_losses = []
test_losses = []
for epoch in range(1, N_EPOCHS + 1):
train_iter = gen_bptt_iter(train_data, BATCH_SIZE, SEQ_LEN, DEVICE)
valid_iter = gen_bptt_iter(valid_data, BATCH_SIZE, SEQ_LEN, DEVICE)