def test_check_scoring_and_check_multimetric_scoring():
check_scoring_validator_for_single_metric_usecases(check_scoring)
# To make sure the check_scoring is correctly applied to the constituent
# scorers
check_scoring_validator_for_single_metric_usecases(
check_multimetric_scoring_single_metric_wrapper)
# For multiple metric use cases
# Make sure it works for the valid cases
for scoring in (('accuracy', ), ['precision'], {
'acc': 'accuracy',
'precision': 'precision'
}, ('accuracy', 'precision'), ['precision', 'accuracy'], {
'accuracy': make_scorer(accuracy_score),
'precision': make_scorer(precision_score)
}):
estimator = LinearSVC(random_state=0)
estimator.fit([[1], [2], [3]], [1, 1, 0])
scorers, is_multi = _check_multimetric_scoring(estimator, scoring)
assert is_multi
assert isinstance(scorers, dict)
assert sorted(scorers.keys()) == sorted(list(scoring))
assert all([
isinstance(scorer, _PredictScorer)
for scorer in list(scorers.values())
])
if 'acc' in scoring:
assert_almost_equal(
scorers['acc'](estimator, [[1], [2], [3]], [1, 0, 0]), 2. / 3.)
if 'accuracy' in scoring:
assert_almost_equal(
scorers['accuracy'](estimator, [[1], [2], [3]], [1, 0, 0]),
2. / 3.)
if 'precision' in scoring:
assert_almost_equal(
scorers['precision'](estimator, [[1], [2], [3]], [1, 0, 0]),
0.5)
estimator = EstimatorWithFitAndPredict()
estimator.fit([[1]], [1])
# Make sure it raises errors when scoring parameter is not valid.
# More weird corner cases are tested at test_validation.py
error_message_regexp = ".*must be unique strings.*"
for scoring in (
(
make_scorer(precision_score), # Tuple of callables
make_scorer(accuracy_score)),
[5],
(make_scorer(precision_score), ),
(),
('f1', 'f1')):
assert_raises_regexp(ValueError,
error_message_regexp,
_check_multimetric_scoring,
estimator,
scoring=scoring)
def test_calibration_multiclass():
"""Test calibration for multiclass """
# test multi-class setting with classifier that implements
# only decision function
clf = LinearSVC()
X, y_idx = make_blobs(n_samples=100, n_features=2, random_state=42,
centers=3, cluster_std=3.0)
# Use categorical labels to check that CalibratedClassifierCV supports
# them correctly
target_names = np.array(['a', 'b', 'c'])
y = target_names[y_idx]
X_train, y_train = X[::2], y[::2]
X_test, y_test = X[1::2], y[1::2]
clf.fit(X_train, y_train)
for method in ['isotonic', 'sigmoid']:
cal_clf = CalibratedClassifierCV(clf, method=method, cv=2)
cal_clf.fit(X_train, y_train)
probas = cal_clf.predict_proba(X_test)
assert_array_almost_equal(np.sum(probas, axis=1), np.ones(len(X_test)))
# Check that log-loss of calibrated classifier is smaller than
# log-loss of naively turned OvR decision function to probabilities
# via softmax
def softmax(y_pred):
e = np.exp(-y_pred)
return e / e.sum(axis=1).reshape(-1, 1)
uncalibrated_log_loss = \
log_loss(y_test, softmax(clf.decision_function(X_test)))
calibrated_log_loss = log_loss(y_test, probas)
assert uncalibrated_log_loss >= calibrated_log_loss
# Test that calibration of a multiclass classifier decreases log-loss
# for RandomForestClassifier
X, y = make_blobs(n_samples=100, n_features=2, random_state=42,
cluster_std=3.0)
X_train, y_train = X[::2], y[::2]
X_test, y_test = X[1::2], y[1::2]
clf = RandomForestClassifier(n_estimators=10, random_state=42)
clf.fit(X_train, y_train)
clf_probs = clf.predict_proba(X_test)
loss = log_loss(y_test, clf_probs)
for method in ['isotonic', 'sigmoid']:
cal_clf = CalibratedClassifierCV(clf, method=method, cv=3)
cal_clf.fit(X_train, y_train)
cal_clf_probs = cal_clf.predict_proba(X_test)
cal_loss = log_loss(y_test, cal_clf_probs)
assert loss > cal_loss
def test_classification_scores():
# Test classification scorers.
X, y = make_blobs(random_state=0, centers=2)
X_train, X_test, y_train, y_test = train_test_split(X, y, random_state=0)
clf = LinearSVC(random_state=0)
clf.fit(X_train, y_train)
for prefix, metric in [('f1', f1_score), ('precision', precision_score),
('recall', recall_score),
('jaccard', jaccard_score)]:
score1 = get_scorer('%s_weighted' % prefix)(clf, X_test, y_test)
score2 = metric(y_test,
clf.predict(X_test),
pos_label=None,
average='weighted')
assert_almost_equal(score1, score2)
score1 = get_scorer('%s_macro' % prefix)(clf, X_test, y_test)
score2 = metric(y_test,
clf.predict(X_test),
pos_label=None,
average='macro')
assert_almost_equal(score1, score2)
score1 = get_scorer('%s_micro' % prefix)(clf, X_test, y_test)
score2 = metric(y_test,
clf.predict(X_test),
pos_label=None,
average='micro')
assert_almost_equal(score1, score2)
score1 = get_scorer('%s' % prefix)(clf, X_test, y_test)
score2 = metric(y_test, clf.predict(X_test), pos_label=1)
assert_almost_equal(score1, score2)
# test fbeta score that takes an argument
scorer = make_scorer(fbeta_score, beta=2)
score1 = scorer(clf, X_test, y_test)
score2 = fbeta_score(y_test, clf.predict(X_test), beta=2)
assert_almost_equal(score1, score2)
# test that custom scorer can be pickled
unpickled_scorer = pickle.loads(pickle.dumps(scorer))
score3 = unpickled_scorer(clf, X_test, y_test)
assert_almost_equal(score1, score3)
# smoke test the repr:
repr(fbeta_score)
def test_random_hasher():
# test random forest hashing on circles dataset
# make sure that it is linearly separable.
# even after projected to two SVD dimensions
# Note: Not all random_states produce perfect results.
hasher = RandomTreesEmbedding(n_estimators=30, random_state=1)
X, y = datasets.make_circles(factor=0.5)
X_transformed = hasher.fit_transform(X)
# test fit and transform:
hasher = RandomTreesEmbedding(n_estimators=30, random_state=1)
assert_array_equal(hasher.fit(X).transform(X).toarray(),
X_transformed.toarray())
# one leaf active per data point per forest
assert X_transformed.shape[0] == X.shape[0]
assert_array_equal(X_transformed.sum(axis=1), hasher.n_estimators)
svd = TruncatedSVD(n_components=2)
X_reduced = svd.fit_transform(X_transformed)
linear_clf = LinearSVC()
linear_clf.fit(X_reduced, y)
assert linear_clf.score(X_reduced, y) == 1.
def test_ovr_fit_predict():
# A classifier which implements decision_function.
ovr = OneVsRestClassifier(LinearSVC(random_state=0))
pred = ovr.fit(iris.data, iris.target).predict(iris.data)
assert len(ovr.estimators_) == n_classes
clf = LinearSVC(random_state=0)
pred2 = clf.fit(iris.data, iris.target).predict(iris.data)
assert np.mean(iris.target == pred) == np.mean(iris.target == pred2)
# A classifier which implements predict_proba.
ovr = OneVsRestClassifier(MultinomialNB())
pred = ovr.fit(iris.data, iris.target).predict(iris.data)
assert np.mean(iris.target == pred) > 0.65
