def load_reranker_model(self,
features_filename,
weights_filename,
feature_class=None):
"""Load the reranker model from its feature and weights files. A
feature class may optionally be specified."""
try:
features_filename = str(features_filename)
except UnicodeEncodeError:
raise ValueError('Reranker features filename %r must be an ASCII '
'string.' % features_filename)
try:
weights_filename = str(weights_filename)
except UnicodeEncodeError:
raise ValueError('Reranker weights filename %r must be an ASCII '
'string.' % weights_filename)
if not exists(features_filename):
raise ValueError('Reranker features filename %r does not exist.' %
features_filename)
if not exists(weights_filename):
raise ValueError('Reranker weights filename %r does not exist.' %
weights_filename)
self.reranker_model = reranker.RerankerModel(feature_class,
features_filename,
weights_filename)
def load_reranker_model(self,
features_filename,
weights_filename,
feature_class=None):
"""Load the reranker model from its feature and weights files. A feature
class may optionally be specified."""
if not os.path.exists(features_filename):
raise ValueError('Reranker features filename %r does not exist.' % \
features_filename)
if not os.path.exists(weights_filename):
raise ValueError('Reranker weights filename %r does not exist.' % \
weights_filename)
self.reranker_model = reranker.RerankerModel(feature_class,
features_filename,
weights_filename)
def rerank(self, reranker, lowercase=True):
"""Rerank this n-best list according to a reranker model. reranker
can be a RerankingParser or RerankerModel."""
assert reranker
if not self.parses:
self._reranked = True
return
if isinstance(reranker, RerankingParser):
reranker = reranker.reranker_model
reranker_input = self.as_reranker_input()
scores = reranker.scoreNBestList(reranker_input)
# this could be more efficient if needed
for (score, nbest_list_item) in zip(scores, self.parses):
nbest_list_item.reranker_score = score
self.sort_by_reranker_scores()
for index, nbest_list_item in enumerate(self.parses):
nbest_list_item.reranker_rank = index
self._reranked = True
def rerank(self, reranker, lowercase=True):
"""Rerank this n-best list according to a reranker model. reranker
can be a RerankingParser or RerankerModel."""
assert reranker
if not self.parses:
self._reranked = True
return
if isinstance(reranker, RerankingParser):
reranker = reranker.reranker_model
reranker_input = self.as_reranker_input()
scores = reranker.scoreNBestList(reranker_input)
# this could be more efficient if needed
for (score, nbest_list_item) in zip(scores, self.parses):
nbest_list_item.reranker_score = score
self.sort_by_reranker_scores()
for index, nbest_list_item in enumerate(self.parses):
nbest_list_item.reranker_rank = index
self._reranked = True
def as_reranker_input(self, lowercase=True):
"""Convert the n-best list to an internal structure used as input
to the reranker. You shouldn't typically need to call this."""
return reranker.readNBestList(str(self), lowercase)
def as_reranker_input(self, lowercase=True):
"""Convert the n-best list to an internal structure used as input
to the reranker. You shouldn't typically need to call this."""
return reranker.readNBestList(str(self), lowercase)
