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from os import truncate
from sacremoses import MosesPunctNormalizer
from sacremoses import MosesTokenizer
from sacremoses import MosesDetokenizer
from subword_nmt.apply_bpe import BPE, read_vocabulary
import codecs
from tqdm import tqdm
from indicnlp.tokenize import indic_tokenize
from indicnlp.tokenize import indic_detokenize
from indicnlp.normalize import indic_normalize
from indicnlp.transliterate import unicode_transliterate
from mosestokenizer import MosesSentenceSplitter
from indicnlp.tokenize import sentence_tokenize
from inference.custom_interactive import Translator
INDIC = ["as", "bn", "gu", "hi", "kn", "ml", "mr", "or", "pa", "ta", "te"]
def split_sentences(paragraph, language):
if language == "en":
with MosesSentenceSplitter(language) as splitter:
return splitter([paragraph])
elif language in INDIC:
return sentence_tokenize.sentence_split(paragraph, lang=language)
def add_token(sent, tag_infos):
"""add special tokens specified by tag_infos to each element in list
tag_infos: list of tuples (tag_type,tag)
each tag_info results in a token of the form: __{tag_type}__{tag}__
"""
tokens = []
for tag_type, tag in tag_infos:
token = "__" + tag_type + "__" + tag + "__"
tokens.append(token)
return " ".join(tokens) + " " + sent
def apply_lang_tags(sents, src_lang, tgt_lang):
tagged_sents = []
for sent in sents:
tagged_sent = add_token(sent.strip(), [("src", src_lang), ("tgt", tgt_lang)])
tagged_sents.append(tagged_sent)
return tagged_sents
def truncate_long_sentences(sents):
MAX_SEQ_LEN = 200
new_sents = []
for sent in sents:
words = sent.split()
num_words = len(words)
if num_words > MAX_SEQ_LEN:
print_str = " ".join(words[:5]) + " .... " + " ".join(words[-5:])
sent = " ".join(words[:MAX_SEQ_LEN])
print(
f"WARNING: Sentence {print_str} truncated to 200 tokens as it exceeds maximum length limit"
)
new_sents.append(sent)
return new_sents
class Model:
def __init__(self, expdir):
self.expdir = expdir
self.en_tok = MosesTokenizer(lang="en")
self.en_normalizer = MosesPunctNormalizer()
self.en_detok = MosesDetokenizer(lang="en")
self.xliterator = unicode_transliterate.UnicodeIndicTransliterator()
print("Initializing vocab and bpe")
self.vocabulary = read_vocabulary(
codecs.open(f"{expdir}/vocab/vocab.SRC", encoding="utf-8"), 5
)
self.bpe = BPE(
codecs.open(f"{expdir}/vocab/bpe_codes.32k.SRC", encoding="utf-8"),
-1,
"@@",
self.vocabulary,
None,
)
print("Initializing model for translation")
# initialize the model
self.translator = Translator(
f"{expdir}/final_bin", f"{expdir}/model/checkpoint_best.pt", batch_size=100
)
# translate a batch of sentences from src_lang to tgt_lang
def batch_translate(self, batch, src_lang, tgt_lang):
assert isinstance(batch, list)
preprocessed_sents = self.preprocess(batch, lang=src_lang)
bpe_sents = self.apply_bpe(preprocessed_sents)
tagged_sents = apply_lang_tags(bpe_sents, src_lang, tgt_lang)
tagged_sents = truncate_long_sentences(tagged_sents)
translations = self.translator.translate(tagged_sents)
postprocessed_sents = self.postprocess(translations, tgt_lang)
return postprocessed_sents
# translate a paragraph from src_lang to tgt_lang
def translate_paragraph(self, paragraph, src_lang, tgt_lang):
assert isinstance(paragraph, str)
sents = split_sentences(paragraph, src_lang)
postprocessed_sents = self.batch_translate(sents, src_lang, tgt_lang)
translated_paragraph = " ".join(postprocessed_sents)
return translated_paragraph
def preprocess_sent(self, sent, normalizer, lang):
if lang == "en":
return " ".join(
self.en_tok.tokenize(
self.en_normalizer.normalize(sent.strip()), escape=False
)
)
else:
# line = indic_detokenize.trivial_detokenize(line.strip(), lang)
return unicode_transliterate.UnicodeIndicTransliterator.transliterate(
" ".join(
indic_tokenize.trivial_tokenize(
normalizer.normalize(sent.strip()), lang
)
),
lang,
"hi",
).replace(" ् ", "्")
def preprocess(self, sents, lang):
"""
Normalize, tokenize and script convert(for Indic)
return number of sentences input file
"""
if lang == "en":
# processed_sents = Parallel(n_jobs=-1, backend="multiprocessing")(
# delayed(preprocess_line)(line, None, lang) for line in tqdm(sents, total=num_lines)
# )
processed_sents = [
self.preprocess_sent(line, None, lang) for line in tqdm(sents)
]
else:
normfactory = indic_normalize.IndicNormalizerFactory()
normalizer = normfactory.get_normalizer(lang)
# processed_sents = Parallel(n_jobs=-1, backend="multiprocessing")(
# delayed(preprocess_line)(line, normalizer, lang) for line in tqdm(infile, total=num_lines)
# )
processed_sents = [
self.preprocess_sent(line, normalizer, lang) for line in tqdm(sents)
]
return processed_sents
def postprocess(self, sents, lang, common_lang="hi"):
"""
parse fairseq interactive output, convert script back to native Indic script (in case of Indic languages) and detokenize.
infname: fairseq log file
outfname: output file of translation (sentences not translated contain the dummy string 'DUMMY_OUTPUT'
input_size: expected number of output sentences
lang: language
"""
postprocessed_sents = []
if lang == "en":
for sent in sents:
# outfile.write(en_detok.detokenize(sent.split(" ")) + "\n")
postprocessed_sents.append(self.en_detok.detokenize(sent.split(" ")))
else:
for sent in sents:
outstr = indic_detokenize.trivial_detokenize(
self.xliterator.transliterate(sent, common_lang, lang), lang
)
# outfile.write(outstr + "\n")
postprocessed_sents.append(outstr)
return postprocessed_sents
def apply_bpe(self, sents):
return [self.bpe.process_line(sent) for sent in sents]