class CRFTagger(ITagger):
def __init__(self, cache_size: Optional[int] = 15000):
self._tagger = crf.load_tagger()
self._tags = crf.load_tags()
extractor = crf.load_extractor()
if cache_size is not None:
extractor = Cache(extractor, size=cache_size)
extractors = {offset: extractor for offset in range(-2, 3)}
self._generator = FeatureWindowGenerator(extractors)
def _get_features(self, text: Text):
for window in self._generator.generate(text, range(len(text))):
yield {
f'{position}:{name}': value
for position, features in window
for name, value in features
}
def tag(self, text: Text, indices: Indices) -> Iterator[Tagged]:
labels = self._tagger.tag(self._get_features(text))
for index in indices:
label = labels[index]
if label:
yield index, self._tags[label]
class LinearTagger(ITagger):
def __init__(self, cache_size: Optional[int] = 15000):
self._coefficients = linear.load_coefficients()
self._intercept = linear.load_intercept()
self._tags = linear.load_tags()
vocabulary = linear.load_vocabulary()
extractor = linear.load_extractor()
if cache_size is not None:
extractor = Cache(extractor, size=cache_size)
extractors = {offset: extractor for offset in vocabulary.keys()}
self._generator = FeatureWindowGenerator(extractors)
self._vectorizer = SparseWindowVectorizer(vocabulary)
def tag(self, text: Text, indices: Indices) -> Iterator[Tagged]:
text = [normalize(word) for word in text]
indices = [index for index in indices if is_cyrillic(text[index])]
windows = self._generator.generate(text, indices)
matrix = self._vectorizer.transform(windows)
labels = (matrix * self._coefficients + self._intercept).argmax(axis=1)
for index, label in zip(indices, labels):
yield index, self._tags[label]
def _assert_windows_equal(
expected: Iterable[FeatureWindow],
generator: FeatureWindowGenerator,
text: Text,
indices: Indices = None,
):
actual = generator.generate(text, indices or range(len(text)))
expected = _unroll(expected)
actual = _unroll(actual)
assert len(expected) == len(actual)
for expected_window, actual_window in zip(expected, actual):
assert expected_window == actual_window
def _assert_windows_equal(expected: Iterable[FeatureWindow],
generator: FeatureWindowGenerator,
text: Text,
indices: Indices = None,
):
actual = generator.generate(text, indices or range(len(text)))
def unroll(windows: Iterable[FeatureWindow]):
return [
[(position, list(features)) for position, features in window]
for window in windows
]
expected = unroll(expected)
actual = unroll(actual)
assert len(expected) == len(actual)
for expected_window, actual_window in zip(expected, actual):
assert expected_window == actual_window