spaCy/bin/wiki_entity_linking/entity_linker_evaluation.py

227 lines
7.9 KiB
Python

import logging
import random
from collections import defaultdict
logger = logging.getLogger(__name__)
class Metrics(object):
true_pos = 0
false_pos = 0
false_neg = 0
def update_results(self, true_entity, candidate):
candidate_is_correct = true_entity == candidate
# Assume that we have no labeled negatives in the data (i.e. cases where true_entity is "NIL")
# Therefore, if candidate_is_correct then we have a true positive and never a true negative.
self.true_pos += candidate_is_correct
self.false_neg += not candidate_is_correct
if candidate and candidate not in {"", "NIL"}:
# A wrong prediction (e.g. Q42 != Q3) counts both as a FP as well as a FN.
self.false_pos += not candidate_is_correct
def calculate_precision(self):
if self.true_pos == 0:
return 0.0
else:
return self.true_pos / (self.true_pos + self.false_pos)
def calculate_recall(self):
if self.true_pos == 0:
return 0.0
else:
return self.true_pos / (self.true_pos + self.false_neg)
def calculate_fscore(self):
p = self.calculate_precision()
r = self.calculate_recall()
if p + r == 0:
return 0.0
else:
return 2 * p * r / (p + r)
class EvaluationResults(object):
def __init__(self):
self.metrics = Metrics()
self.metrics_by_label = defaultdict(Metrics)
def update_metrics(self, ent_label, true_entity, candidate):
self.metrics.update_results(true_entity, candidate)
self.metrics_by_label[ent_label].update_results(true_entity, candidate)
def report_metrics(self, model_name):
model_str = model_name.title()
recall = self.metrics.calculate_recall()
precision = self.metrics.calculate_precision()
fscore = self.metrics.calculate_fscore()
return (
"{}: ".format(model_str)
+ "F-score = {} | ".format(round(fscore, 3))
+ "Recall = {} | ".format(round(recall, 3))
+ "Precision = {} | ".format(round(precision, 3))
+ "F-score by label = {}".format(
{k: v.calculate_fscore() for k, v in sorted(self.metrics_by_label.items())}
)
)
class BaselineResults(object):
def __init__(self):
self.random = EvaluationResults()
self.prior = EvaluationResults()
self.oracle = EvaluationResults()
def report_performance(self, model):
results = getattr(self, model)
return results.report_metrics(model)
def update_baselines(
self,
true_entity,
ent_label,
random_candidate,
prior_candidate,
oracle_candidate,
):
self.oracle.update_metrics(ent_label, true_entity, oracle_candidate)
self.prior.update_metrics(ent_label, true_entity, prior_candidate)
self.random.update_metrics(ent_label, true_entity, random_candidate)
def measure_performance(dev_data, kb, el_pipe, baseline=True, context=True):
if baseline:
baseline_accuracies, counts = measure_baselines(dev_data, kb)
logger.info("Counts: {}".format({k: v for k, v in sorted(counts.items())}))
logger.info(baseline_accuracies.report_performance("random"))
logger.info(baseline_accuracies.report_performance("prior"))
logger.info(baseline_accuracies.report_performance("oracle"))
if context:
# using only context
el_pipe.cfg["incl_context"] = True
el_pipe.cfg["incl_prior"] = False
results = get_eval_results(dev_data, el_pipe)
logger.info(results.report_metrics("context only"))
# measuring combined accuracy (prior + context)
el_pipe.cfg["incl_context"] = True
el_pipe.cfg["incl_prior"] = True
results = get_eval_results(dev_data, el_pipe)
logger.info(results.report_metrics("context and prior"))
def get_eval_results(data, el_pipe=None):
"""
Evaluate the ent.kb_id_ annotations against the gold standard.
Only evaluate entities that overlap between gold and NER, to isolate the performance of the NEL.
If the docs in the data require further processing with an entity linker, set el_pipe.
"""
from tqdm import tqdm
docs = []
golds = []
for d, g in tqdm(data, leave=False):
if len(d) > 0:
golds.append(g)
if el_pipe is not None:
docs.append(el_pipe(d))
else:
docs.append(d)
results = EvaluationResults()
for doc, gold in zip(docs, golds):
try:
correct_entries_per_article = dict()
for entity, kb_dict in gold.links.items():
start, end = entity
for gold_kb, value in kb_dict.items():
if value:
# only evaluating on positive examples
offset = _offset(start, end)
correct_entries_per_article[offset] = gold_kb
for ent in doc.ents:
ent_label = ent.label_
pred_entity = ent.kb_id_
start = ent.start_char
end = ent.end_char
offset = _offset(start, end)
gold_entity = correct_entries_per_article.get(offset, None)
# the gold annotations are not complete so we can't evaluate missing annotations as 'wrong'
if gold_entity is not None:
results.update_metrics(ent_label, gold_entity, pred_entity)
except Exception as e:
logging.error("Error assessing accuracy " + str(e))
return results
def measure_baselines(data, kb):
"""
Measure 3 performance baselines: random selection, prior probabilities, and 'oracle' prediction for upper bound.
Only evaluate entities that overlap between gold and NER, to isolate the performance of the NEL.
Also return a dictionary of counts by entity label.
"""
counts_d = dict()
baseline_results = BaselineResults()
docs = [d for d, g in data if len(d) > 0]
golds = [g for d, g in data if len(d) > 0]
for doc, gold in zip(docs, golds):
correct_entries_per_article = dict()
for entity, kb_dict in gold.links.items():
start, end = entity
for gold_kb, value in kb_dict.items():
# only evaluating on positive examples
if value:
offset = _offset(start, end)
correct_entries_per_article[offset] = gold_kb
for ent in doc.ents:
ent_label = ent.label_
start = ent.start_char
end = ent.end_char
offset = _offset(start, end)
gold_entity = correct_entries_per_article.get(offset, None)
# the gold annotations are not complete so we can't evaluate missing annotations as 'wrong'
if gold_entity is not None:
candidates = kb.get_candidates(ent.text)
oracle_candidate = ""
prior_candidate = ""
random_candidate = ""
if candidates:
scores = []
for c in candidates:
scores.append(c.prior_prob)
if c.entity_ == gold_entity:
oracle_candidate = c.entity_
best_index = scores.index(max(scores))
prior_candidate = candidates[best_index].entity_
random_candidate = random.choice(candidates).entity_
current_count = counts_d.get(ent_label, 0)
counts_d[ent_label] = current_count+1
baseline_results.update_baselines(
gold_entity,
ent_label,
random_candidate,
prior_candidate,
oracle_candidate,
)
return baseline_results, counts_d
def _offset(start, end):
return "{}_{}".format(start, end)