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scikit-learn/sklearn/metrics/tests/test_score_objects.py

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import pickle
import tempfile
import shutil
import os
import numbers
from unittest.mock import Mock
from functools import partial
import numpy as np
import pytest
import joblib
from numpy.testing import assert_allclose
from sklearn.utils._testing import assert_almost_equal
from sklearn.utils._testing import assert_array_equal
from sklearn.utils._testing import ignore_warnings
from sklearn.base import BaseEstimator
from sklearn.metrics import (f1_score, r2_score, roc_auc_score, fbeta_score,
log_loss, precision_score, recall_score,
jaccard_score)
from sklearn.metrics import cluster as cluster_module
from sklearn.metrics import check_scoring
from sklearn.metrics._scorer import (_PredictScorer, _passthrough_scorer,
_MultimetricScorer,
_check_multimetric_scoring)
from sklearn.metrics import accuracy_score
from sklearn.metrics import make_scorer, get_scorer, SCORERS
from sklearn.neighbors import KNeighborsClassifier
from sklearn.svm import LinearSVC
from sklearn.pipeline import make_pipeline
from sklearn.cluster import KMeans
from sklearn.linear_model import Ridge, LogisticRegression, Perceptron
from sklearn.tree import DecisionTreeClassifier, DecisionTreeRegressor
from sklearn.datasets import make_blobs
from sklearn.datasets import make_classification, make_regression
from sklearn.datasets import make_multilabel_classification
from sklearn.datasets import load_diabetes
from sklearn.model_selection import train_test_split, cross_val_score
from sklearn.model_selection import GridSearchCV
from sklearn.multiclass import OneVsRestClassifier
REGRESSION_SCORERS = ['explained_variance', 'r2',
'neg_mean_absolute_error', 'neg_mean_squared_error',
'neg_mean_absolute_percentage_error',
'neg_mean_squared_log_error',
'neg_median_absolute_error',
'neg_root_mean_squared_error',
'mean_absolute_error',
'mean_absolute_percentage_error',
'mean_squared_error', 'median_absolute_error',
'max_error', 'neg_mean_poisson_deviance',
'neg_mean_gamma_deviance']
CLF_SCORERS = ['accuracy', 'balanced_accuracy',
'f1', 'f1_weighted', 'f1_macro', 'f1_micro',
'roc_auc', 'average_precision', 'precision',
'precision_weighted', 'precision_macro', 'precision_micro',
'recall', 'recall_weighted', 'recall_macro', 'recall_micro',
'neg_log_loss', 'log_loss', 'neg_brier_score',
'jaccard', 'jaccard_weighted', 'jaccard_macro',
'jaccard_micro', 'roc_auc_ovr', 'roc_auc_ovo',
'roc_auc_ovr_weighted', 'roc_auc_ovo_weighted']
# All supervised cluster scorers (They behave like classification metric)
CLUSTER_SCORERS = ["adjusted_rand_score",
"homogeneity_score",
"completeness_score",
"v_measure_score",
"mutual_info_score",
"adjusted_mutual_info_score",
"normalized_mutual_info_score",
"fowlkes_mallows_score"]
MULTILABEL_ONLY_SCORERS = ['precision_samples', 'recall_samples', 'f1_samples',
'jaccard_samples']
REQUIRE_POSITIVE_Y_SCORERS = ['neg_mean_poisson_deviance',
'neg_mean_gamma_deviance']
def _require_positive_y(y):
"""Make targets strictly positive"""
offset = abs(y.min()) + 1
y = y + offset
return y
def _make_estimators(X_train, y_train, y_ml_train):
# Make estimators that make sense to test various scoring methods
sensible_regr = DecisionTreeRegressor(random_state=0)
# some of the regressions scorers require strictly positive input.
sensible_regr.fit(X_train, _require_positive_y(y_train))
sensible_clf = DecisionTreeClassifier(random_state=0)
sensible_clf.fit(X_train, y_train)
sensible_ml_clf = DecisionTreeClassifier(random_state=0)
sensible_ml_clf.fit(X_train, y_ml_train)
return dict(
[(name, sensible_regr) for name in REGRESSION_SCORERS] +
[(name, sensible_clf) for name in CLF_SCORERS] +
[(name, sensible_clf) for name in CLUSTER_SCORERS] +
[(name, sensible_ml_clf) for name in MULTILABEL_ONLY_SCORERS]
)
X_mm, y_mm, y_ml_mm = None, None, None
ESTIMATORS = None
TEMP_FOLDER = None
def setup_module():
# Create some memory mapped data
global X_mm, y_mm, y_ml_mm, TEMP_FOLDER, ESTIMATORS
TEMP_FOLDER = tempfile.mkdtemp(prefix='sklearn_test_score_objects_')
X, y = make_classification(n_samples=30, n_features=5, random_state=0)
_, y_ml = make_multilabel_classification(n_samples=X.shape[0],
random_state=0)
filename = os.path.join(TEMP_FOLDER, 'test_data.pkl')
joblib.dump((X, y, y_ml), filename)
X_mm, y_mm, y_ml_mm = joblib.load(filename, mmap_mode='r')
ESTIMATORS = _make_estimators(X_mm, y_mm, y_ml_mm)
def teardown_module():
global X_mm, y_mm, y_ml_mm, TEMP_FOLDER, ESTIMATORS
# GC closes the mmap file descriptors
X_mm, y_mm, y_ml_mm, ESTIMATORS = None, None, None, None
shutil.rmtree(TEMP_FOLDER)
class EstimatorWithoutFit:
"""Dummy estimator to test scoring validators"""
pass
class EstimatorWithFit(BaseEstimator):
"""Dummy estimator to test scoring validators"""
def fit(self, X, y):
return self
class EstimatorWithFitAndScore:
"""Dummy estimator to test scoring validators"""
def fit(self, X, y):
return self
def score(self, X, y):
return 1.0
class EstimatorWithFitAndPredict:
"""Dummy estimator to test scoring validators"""
def fit(self, X, y):
self.y = y
return self
def predict(self, X):
return self.y
class DummyScorer:
"""Dummy scorer that always returns 1."""
def __call__(self, est, X, y):
return 1
def test_all_scorers_repr():
# Test that all scorers have a working repr
for name, scorer in SCORERS.items():
repr(scorer)
def check_scoring_validator_for_single_metric_usecases(scoring_validator):
# Test all branches of single metric usecases
estimator = EstimatorWithoutFit()
pattern = (r"estimator should be an estimator implementing 'fit' method,"
r" .* was passed")
with pytest.raises(TypeError, match=pattern):
scoring_validator(estimator)
estimator = EstimatorWithFitAndScore()
estimator.fit([[1]], [1])
scorer = scoring_validator(estimator)
assert scorer is _passthrough_scorer
assert_almost_equal(scorer(estimator, [[1]], [1]), 1.0)
estimator = EstimatorWithFitAndPredict()
estimator.fit([[1]], [1])
pattern = (r"If no scoring is specified, the estimator passed should have"
r" a 'score' method\. The estimator .* does not\.")
with pytest.raises(TypeError, match=pattern):
scoring_validator(estimator)
scorer = scoring_validator(estimator, scoring="accuracy")
assert_almost_equal(scorer(estimator, [[1]], [1]), 1.0)
estimator = EstimatorWithFit()
scorer = scoring_validator(estimator, scoring="accuracy")
assert isinstance(scorer, _PredictScorer)
# Test the allow_none parameter for check_scoring alone
if scoring_validator is check_scoring:
estimator = EstimatorWithFit()
scorer = scoring_validator(estimator, allow_none=True)
assert scorer is None
@pytest.mark.parametrize(
"scoring",
(
('accuracy', ), ['precision'],
{'acc': 'accuracy', 'precision': 'precision'},
('accuracy', 'precision'),
['precision', 'accuracy'],
{'accuracy': make_scorer(accuracy_score),
'precision': make_scorer(precision_score)}
), ids=["single_tuple", "single_list", "dict_str",
"multi_tuple", "multi_list", "dict_callable"])
def test_check_scoring_and_check_multimetric_scoring(scoring):
check_scoring_validator_for_single_metric_usecases(check_scoring)
# To make sure the check_scoring is correctly applied to the constituent
# scorers
estimator = LinearSVC(random_state=0)
estimator.fit([[1], [2], [3]], [1, 1, 0])
scorers = _check_multimetric_scoring(estimator, scoring)
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)
@pytest.mark.parametrize("scoring", [
((make_scorer(precision_score), make_scorer(accuracy_score)),
"One or more of the elements were callables"),
([5], "Non-string types were found"),
((make_scorer(precision_score), ),
"One of mor eof the elements were callables"),
((), "Empty list was given"),
(('f1', 'f1'), "Duplicate elements were found"),
({4: 'accuracy'}, "Non-string types were found in the keys"),
({}, "An empty dict was passed"),
], ids=[
"tuple of callables", "list of int",
"tuple of one callable", "empty tuple",
"non-unique str", "non-string key dict",
"empty dict"])
def test_check_scoring_and_check_multimetric_scoring_errors(scoring):
# Make sure it raises errors when scoring parameter is not valid.
# More weird corner cases are tested at test_validation.py
estimator = EstimatorWithFitAndPredict()
estimator.fit([[1]], [1])
error_message_regexp = ".*must be unique strings.*"
with pytest.raises(ValueError, match=error_message_regexp):
_check_multimetric_scoring(estimator, scoring=scoring)
def test_check_scoring_gridsearchcv():
# test that check_scoring works on GridSearchCV and pipeline.
# slightly redundant non-regression test.
grid = GridSearchCV(LinearSVC(), param_grid={'C': [.1, 1]}, cv=3)
scorer = check_scoring(grid, scoring="f1")
assert isinstance(scorer, _PredictScorer)
pipe = make_pipeline(LinearSVC())
scorer = check_scoring(pipe, scoring="f1")
assert isinstance(scorer, _PredictScorer)
# check that cross_val_score definitely calls the scorer
# and doesn't make any assumptions about the estimator apart from having a
# fit.
scores = cross_val_score(EstimatorWithFit(), [[1], [2], [3]], [1, 0, 1],
scoring=DummyScorer(), cv=3)
assert_array_equal(scores, 1)
def test_make_scorer():
# Sanity check on the make_scorer factory function.
f = lambda *args: 0
with pytest.raises(ValueError):
make_scorer(f, needs_threshold=True, needs_proba=True)
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_regression_scorers():
# Test regression scorers.
diabetes = load_diabetes()
X, y = diabetes.data, diabetes.target
X_train, X_test, y_train, y_test = train_test_split(X, y, random_state=0)
clf = Ridge()
clf.fit(X_train, y_train)
score1 = get_scorer('r2')(clf, X_test, y_test)
score2 = r2_score(y_test, clf.predict(X_test))
assert_almost_equal(score1, score2)
def test_thresholded_scorers():
# Test scorers that take thresholds.
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 = LogisticRegression(random_state=0)
clf.fit(X_train, y_train)
score1 = get_scorer('roc_auc')(clf, X_test, y_test)
score2 = roc_auc_score(y_test, clf.decision_function(X_test))
score3 = roc_auc_score(y_test, clf.predict_proba(X_test)[:, 1])
assert_almost_equal(score1, score2)
assert_almost_equal(score1, score3)
logscore = get_scorer('neg_log_loss')(clf, X_test, y_test)
logloss = log_loss(y_test, clf.predict_proba(X_test))
assert_almost_equal(-logscore, logloss)
# same for an estimator without decision_function
clf = DecisionTreeClassifier()
clf.fit(X_train, y_train)
score1 = get_scorer('roc_auc')(clf, X_test, y_test)
score2 = roc_auc_score(y_test, clf.predict_proba(X_test)[:, 1])
assert_almost_equal(score1, score2)
# test with a regressor (no decision_function)
reg = DecisionTreeRegressor()
reg.fit(X_train, y_train)
score1 = get_scorer('roc_auc')(reg, X_test, y_test)
score2 = roc_auc_score(y_test, reg.predict(X_test))
assert_almost_equal(score1, score2)
# Test that an exception is raised on more than two classes
X, y = make_blobs(random_state=0, centers=3)
X_train, X_test, y_train, y_test = train_test_split(X, y, random_state=0)
clf.fit(X_train, y_train)
with pytest.raises(ValueError, match="multiclass format is not supported"):
get_scorer('roc_auc')(clf, X_test, y_test)
# test error is raised with a single class present in model
# (predict_proba shape is not suitable for binary auc)
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 = DecisionTreeClassifier()
clf.fit(X_train, np.zeros_like(y_train))
with pytest.raises(ValueError, match="need classifier with two classes"):
get_scorer('roc_auc')(clf, X_test, y_test)
# for proba scorers
with pytest.raises(ValueError, match="need classifier with two classes"):
get_scorer('neg_log_loss')(clf, X_test, y_test)
def test_thresholded_scorers_multilabel_indicator_data():
# Test that the scorer work with multilabel-indicator format
# for multilabel and multi-output multi-class classifier
X, y = make_multilabel_classification(allow_unlabeled=False,
random_state=0)
X_train, X_test, y_train, y_test = train_test_split(X, y, random_state=0)
# Multi-output multi-class predict_proba
clf = DecisionTreeClassifier()
clf.fit(X_train, y_train)
y_proba = clf.predict_proba(X_test)
score1 = get_scorer('roc_auc')(clf, X_test, y_test)
score2 = roc_auc_score(y_test, np.vstack([p[:, -1] for p in y_proba]).T)
assert_almost_equal(score1, score2)
# Multi-output multi-class decision_function
# TODO Is there any yet?
clf = DecisionTreeClassifier()
clf.fit(X_train, y_train)
clf._predict_proba = clf.predict_proba
clf.predict_proba = None
clf.decision_function = lambda X: [p[:, 1] for p in clf._predict_proba(X)]
y_proba = clf.decision_function(X_test)
score1 = get_scorer('roc_auc')(clf, X_test, y_test)
score2 = roc_auc_score(y_test, np.vstack([p for p in y_proba]).T)
assert_almost_equal(score1, score2)
# Multilabel predict_proba
clf = OneVsRestClassifier(DecisionTreeClassifier())
clf.fit(X_train, y_train)
score1 = get_scorer('roc_auc')(clf, X_test, y_test)
score2 = roc_auc_score(y_test, clf.predict_proba(X_test))
assert_almost_equal(score1, score2)
# Multilabel decision function
clf = OneVsRestClassifier(LinearSVC(random_state=0))
clf.fit(X_train, y_train)
score1 = get_scorer('roc_auc')(clf, X_test, y_test)
score2 = roc_auc_score(y_test, clf.decision_function(X_test))
assert_almost_equal(score1, score2)
def test_supervised_cluster_scorers():
# Test clustering scorers against gold standard labeling.
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)
km = KMeans(n_clusters=3)
km.fit(X_train)
for name in CLUSTER_SCORERS:
score1 = get_scorer(name)(km, X_test, y_test)
score2 = getattr(cluster_module, name)(y_test, km.predict(X_test))
assert_almost_equal(score1, score2)
@ignore_warnings
def test_raises_on_score_list():
# Test that when a list of scores is returned, we raise proper errors.
X, y = make_blobs(random_state=0)
f1_scorer_no_average = make_scorer(f1_score, average=None)
clf = DecisionTreeClassifier()
with pytest.raises(ValueError):
cross_val_score(clf, X, y, scoring=f1_scorer_no_average)
grid_search = GridSearchCV(clf, scoring=f1_scorer_no_average,
param_grid={'max_depth': [1, 2]})
with pytest.raises(ValueError):
grid_search.fit(X, y)
@ignore_warnings
def test_classification_scorer_sample_weight():
# Test that classification scorers support sample_weight or raise sensible
# errors
# Unlike the metrics invariance test, in the scorer case it's harder
# to ensure that, on the classifier output, weighted and unweighted
# scores really should be unequal.
X, y = make_classification(random_state=0)
_, y_ml = make_multilabel_classification(n_samples=X.shape[0],
random_state=0)
split = train_test_split(X, y, y_ml, random_state=0)
X_train, X_test, y_train, y_test, y_ml_train, y_ml_test = split
sample_weight = np.ones_like(y_test)
sample_weight[:10] = 0
# get sensible estimators for each metric
estimator = _make_estimators(X_train, y_train, y_ml_train)
for name, scorer in SCORERS.items():
if name in REGRESSION_SCORERS:
# skip the regression scores
continue
if name in MULTILABEL_ONLY_SCORERS:
target = y_ml_test
else:
target = y_test
try:
weighted = scorer(estimator[name], X_test, target,
sample_weight=sample_weight)
ignored = scorer(estimator[name], X_test[10:], target[10:])
unweighted = scorer(estimator[name], X_test, target)
assert weighted != unweighted, (
f"scorer {name} behaves identically when called with "
f"sample weights: {weighted} vs {unweighted}")
assert_almost_equal(weighted, ignored,
err_msg=f"scorer {name} behaves differently "
f"when ignoring samples and setting "
f"sample_weight to 0: {weighted} vs {ignored}")
except TypeError as e:
assert "sample_weight" in str(e), (
f"scorer {name} raises unhelpful exception when called "
f"with sample weights: {str(e)}")
@ignore_warnings
def test_regression_scorer_sample_weight():
# Test that regression scorers support sample_weight or raise sensible
# errors
# Odd number of test samples req for neg_median_absolute_error
X, y = make_regression(n_samples=101, n_features=20, random_state=0)
y = _require_positive_y(y)
X_train, X_test, y_train, y_test = train_test_split(X, y, random_state=0)
sample_weight = np.ones_like(y_test)
# Odd number req for neg_median_absolute_error
sample_weight[:11] = 0
reg = DecisionTreeRegressor(random_state=0)
reg.fit(X_train, y_train)
for name, scorer in SCORERS.items():
if name not in REGRESSION_SCORERS:
# skip classification scorers
continue
try:
weighted = scorer(reg, X_test, y_test,
sample_weight=sample_weight)
ignored = scorer(reg, X_test[11:], y_test[11:])
unweighted = scorer(reg, X_test, y_test)
assert weighted != unweighted, (
f"scorer {name} behaves identically when called with "
f"sample weights: {weighted} vs {unweighted}")
assert_almost_equal(weighted, ignored,
err_msg=f"scorer {name} behaves differently "
f"when ignoring samples and setting "
f"sample_weight to 0: {weighted} vs {ignored}")
except TypeError as e:
assert "sample_weight" in str(e), (
f"scorer {name} raises unhelpful exception when called "
f"with sample weights: {str(e)}")
@pytest.mark.parametrize('name', SCORERS)
def test_scorer_memmap_input(name):
# Non-regression test for #6147: some score functions would
# return singleton memmap when computed on memmap data instead of scalar
# float values.
if name in REQUIRE_POSITIVE_Y_SCORERS:
y_mm_1 = _require_positive_y(y_mm)
y_ml_mm_1 = _require_positive_y(y_ml_mm)
else:
y_mm_1, y_ml_mm_1 = y_mm, y_ml_mm
# UndefinedMetricWarning for P / R scores
with ignore_warnings():
scorer, estimator = SCORERS[name], ESTIMATORS[name]
if name in MULTILABEL_ONLY_SCORERS:
score = scorer(estimator, X_mm, y_ml_mm_1)
else:
score = scorer(estimator, X_mm, y_mm_1)
assert isinstance(score, numbers.Number), name
def test_scoring_is_not_metric():
with pytest.raises(ValueError, match='make_scorer'):
check_scoring(LogisticRegression(), scoring=f1_score)
with pytest.raises(ValueError, match='make_scorer'):
check_scoring(LogisticRegression(), scoring=roc_auc_score)
with pytest.raises(ValueError, match='make_scorer'):
check_scoring(Ridge(), scoring=r2_score)
with pytest.raises(ValueError, match='make_scorer'):
check_scoring(KMeans(), scoring=cluster_module.adjusted_rand_score)
@pytest.mark.parametrize(
("scorers,expected_predict_count,"
"expected_predict_proba_count,expected_decision_func_count"),
[({'a1': 'accuracy', 'a2': 'accuracy',
'll1': 'neg_log_loss', 'll2': 'neg_log_loss',
'ra1': 'roc_auc', 'ra2': 'roc_auc'}, 1, 1, 1),
(['roc_auc', 'accuracy'], 1, 0, 1),
(['neg_log_loss', 'accuracy'], 1, 1, 0)])
def test_multimetric_scorer_calls_method_once(scorers, expected_predict_count,
expected_predict_proba_count,
expected_decision_func_count):
X, y = np.array([[1], [1], [0], [0], [0]]), np.array([0, 1, 1, 1, 0])
mock_est = Mock()
fit_func = Mock(return_value=mock_est)
predict_func = Mock(return_value=y)
pos_proba = np.random.rand(X.shape[0])
proba = np.c_[1 - pos_proba, pos_proba]
predict_proba_func = Mock(return_value=proba)
decision_function_func = Mock(return_value=pos_proba)
mock_est.fit = fit_func
mock_est.predict = predict_func
mock_est.predict_proba = predict_proba_func
mock_est.decision_function = decision_function_func
scorer_dict = _check_multimetric_scoring(LogisticRegression(), scorers)
multi_scorer = _MultimetricScorer(**scorer_dict)
results = multi_scorer(mock_est, X, y)
assert set(scorers) == set(results) # compare dict keys
assert predict_func.call_count == expected_predict_count
assert predict_proba_func.call_count == expected_predict_proba_count
assert decision_function_func.call_count == expected_decision_func_count
def test_multimetric_scorer_calls_method_once_classifier_no_decision():
predict_proba_call_cnt = 0
class MockKNeighborsClassifier(KNeighborsClassifier):
def predict_proba(self, X):
nonlocal predict_proba_call_cnt
predict_proba_call_cnt += 1
return super().predict_proba(X)
X, y = np.array([[1], [1], [0], [0], [0]]), np.array([0, 1, 1, 1, 0])
# no decision function
clf = MockKNeighborsClassifier(n_neighbors=1)
clf.fit(X, y)
scorers = ['roc_auc', 'neg_log_loss']
scorer_dict = _check_multimetric_scoring(clf, scorers)
scorer = _MultimetricScorer(**scorer_dict)
scorer(clf, X, y)
assert predict_proba_call_cnt == 1
def test_multimetric_scorer_calls_method_once_regressor_threshold():
predict_called_cnt = 0
class MockDecisionTreeRegressor(DecisionTreeRegressor):
def predict(self, X):
nonlocal predict_called_cnt
predict_called_cnt += 1
return super().predict(X)
X, y = np.array([[1], [1], [0], [0], [0]]), np.array([0, 1, 1, 1, 0])
# no decision function
clf = MockDecisionTreeRegressor()
clf.fit(X, y)
scorers = {'neg_mse': 'neg_mean_squared_error', 'r2': 'roc_auc'}
scorer_dict = _check_multimetric_scoring(clf, scorers)
scorer = _MultimetricScorer(**scorer_dict)
scorer(clf, X, y)
assert predict_called_cnt == 1
def test_multimetric_scorer_sanity_check():
# scoring dictionary returned is the same as calling each scorer separately
scorers = {'a1': 'accuracy', 'a2': 'accuracy',
'll1': 'neg_log_loss', 'll2': 'neg_log_loss',
'ra1': 'roc_auc', 'ra2': 'roc_auc'}
X, y = make_classification(random_state=0)
clf = DecisionTreeClassifier()
clf.fit(X, y)
scorer_dict = _check_multimetric_scoring(clf, scorers)
multi_scorer = _MultimetricScorer(**scorer_dict)
result = multi_scorer(clf, X, y)
separate_scores = {
name: get_scorer(name)(clf, X, y)
for name in ['accuracy', 'neg_log_loss', 'roc_auc']}
for key, value in result.items():
score_name = scorers[key]
assert_allclose(value, separate_scores[score_name])
@pytest.mark.parametrize('scorer_name, metric', [
('roc_auc_ovr', partial(roc_auc_score, multi_class='ovr')),
('roc_auc_ovo', partial(roc_auc_score, multi_class='ovo')),
('roc_auc_ovr_weighted', partial(roc_auc_score, multi_class='ovr',
average='weighted')),
('roc_auc_ovo_weighted', partial(roc_auc_score, multi_class='ovo',
average='weighted'))])
def test_multiclass_roc_proba_scorer(scorer_name, metric):
scorer = get_scorer(scorer_name)
X, y = make_classification(n_classes=3, n_informative=3, n_samples=20,
random_state=0)
lr = LogisticRegression(multi_class="multinomial").fit(X, y)
y_proba = lr.predict_proba(X)
expected_score = metric(y, y_proba)
assert scorer(lr, X, y) == pytest.approx(expected_score)
def test_multiclass_roc_proba_scorer_label():
scorer = make_scorer(roc_auc_score, multi_class='ovo',
labels=[0, 1, 2], needs_proba=True)
X, y = make_classification(n_classes=3, n_informative=3, n_samples=20,
random_state=0)
lr = LogisticRegression(multi_class="multinomial").fit(X, y)
y_proba = lr.predict_proba(X)
y_binary = y == 0
expected_score = roc_auc_score(y_binary, y_proba,
multi_class='ovo',
labels=[0, 1, 2])
assert scorer(lr, X, y_binary) == pytest.approx(expected_score)
@pytest.mark.parametrize('scorer_name', [
'roc_auc_ovr', 'roc_auc_ovo',
'roc_auc_ovr_weighted', 'roc_auc_ovo_weighted'])
def test_multiclass_roc_no_proba_scorer_errors(scorer_name):
# Perceptron has no predict_proba
scorer = get_scorer(scorer_name)
X, y = make_classification(n_classes=3, n_informative=3, n_samples=20,
random_state=0)
lr = Perceptron().fit(X, y)
msg = "'Perceptron' object has no attribute 'predict_proba'"
with pytest.raises(AttributeError, match=msg):
scorer(lr, X, y)
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