projektAI/venv/Lib/site-packages/sklearn/ensemble/tests/test_weight_boosting.py
2021-06-06 22:13:05 +02:00

581 lines
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Python

"""Testing for the boost module (sklearn.ensemble.boost)."""
import numpy as np
import pytest
from scipy.sparse import csc_matrix
from scipy.sparse import csr_matrix
from scipy.sparse import coo_matrix
from scipy.sparse import dok_matrix
from scipy.sparse import lil_matrix
from sklearn.utils._testing import assert_array_equal, assert_array_less
from sklearn.utils._testing import assert_array_almost_equal
from sklearn.utils._testing import assert_raises, assert_raises_regexp
from sklearn.base import BaseEstimator
from sklearn.base import clone
from sklearn.dummy import DummyClassifier, DummyRegressor
from sklearn.linear_model import LinearRegression
from sklearn.model_selection import train_test_split
from sklearn.model_selection import GridSearchCV
from sklearn.ensemble import AdaBoostClassifier
from sklearn.ensemble import AdaBoostRegressor
from sklearn.ensemble._weight_boosting import _samme_proba
from sklearn.svm import SVC, SVR
from sklearn.tree import DecisionTreeClassifier, DecisionTreeRegressor
from sklearn.utils import shuffle
from sklearn.utils._mocking import NoSampleWeightWrapper
from sklearn import datasets
# Common random state
rng = np.random.RandomState(0)
# Toy sample
X = [[-2, -1], [-1, -1], [-1, -2], [1, 1], [1, 2], [2, 1]]
y_class = ["foo", "foo", "foo", 1, 1, 1] # test string class labels
y_regr = [-1, -1, -1, 1, 1, 1]
T = [[-1, -1], [2, 2], [3, 2]]
y_t_class = ["foo", 1, 1]
y_t_regr = [-1, 1, 1]
# Load the iris dataset and randomly permute it
iris = datasets.load_iris()
perm = rng.permutation(iris.target.size)
iris.data, iris.target = shuffle(iris.data, iris.target, random_state=rng)
# Load the diabetes dataset and randomly permute it
diabetes = datasets.load_diabetes()
diabetes.data, diabetes.target = shuffle(diabetes.data, diabetes.target,
random_state=rng)
def test_samme_proba():
# Test the `_samme_proba` helper function.
# Define some example (bad) `predict_proba` output.
probs = np.array([[1, 1e-6, 0],
[0.19, 0.6, 0.2],
[-999, 0.51, 0.5],
[1e-6, 1, 1e-9]])
probs /= np.abs(probs.sum(axis=1))[:, np.newaxis]
# _samme_proba calls estimator.predict_proba.
# Make a mock object so I can control what gets returned.
class MockEstimator:
def predict_proba(self, X):
assert_array_equal(X.shape, probs.shape)
return probs
mock = MockEstimator()
samme_proba = _samme_proba(mock, 3, np.ones_like(probs))
assert_array_equal(samme_proba.shape, probs.shape)
assert np.isfinite(samme_proba).all()
# Make sure that the correct elements come out as smallest --
# `_samme_proba` should preserve the ordering in each example.
assert_array_equal(np.argmin(samme_proba, axis=1), [2, 0, 0, 2])
assert_array_equal(np.argmax(samme_proba, axis=1), [0, 1, 1, 1])
def test_oneclass_adaboost_proba():
# Test predict_proba robustness for one class label input.
# In response to issue #7501
# https://github.com/scikit-learn/scikit-learn/issues/7501
y_t = np.ones(len(X))
clf = AdaBoostClassifier().fit(X, y_t)
assert_array_almost_equal(clf.predict_proba(X), np.ones((len(X), 1)))
@pytest.mark.parametrize("algorithm", ["SAMME", "SAMME.R"])
def test_classification_toy(algorithm):
# Check classification on a toy dataset.
clf = AdaBoostClassifier(algorithm=algorithm, random_state=0)
clf.fit(X, y_class)
assert_array_equal(clf.predict(T), y_t_class)
assert_array_equal(np.unique(np.asarray(y_t_class)), clf.classes_)
assert clf.predict_proba(T).shape == (len(T), 2)
assert clf.decision_function(T).shape == (len(T),)
def test_regression_toy():
# Check classification on a toy dataset.
clf = AdaBoostRegressor(random_state=0)
clf.fit(X, y_regr)
assert_array_equal(clf.predict(T), y_t_regr)
def test_iris():
# Check consistency on dataset iris.
classes = np.unique(iris.target)
clf_samme = prob_samme = None
for alg in ['SAMME', 'SAMME.R']:
clf = AdaBoostClassifier(algorithm=alg)
clf.fit(iris.data, iris.target)
assert_array_equal(classes, clf.classes_)
proba = clf.predict_proba(iris.data)
if alg == "SAMME":
clf_samme = clf
prob_samme = proba
assert proba.shape[1] == len(classes)
assert clf.decision_function(iris.data).shape[1] == len(classes)
score = clf.score(iris.data, iris.target)
assert score > 0.9, "Failed with algorithm %s and score = %f" % \
(alg, score)
# Check we used multiple estimators
assert len(clf.estimators_) > 1
# Check for distinct random states (see issue #7408)
assert (len(set(est.random_state for est in clf.estimators_)) ==
len(clf.estimators_))
# Somewhat hacky regression test: prior to
# ae7adc880d624615a34bafdb1d75ef67051b8200,
# predict_proba returned SAMME.R values for SAMME.
clf_samme.algorithm = "SAMME.R"
assert_array_less(0,
np.abs(clf_samme.predict_proba(iris.data) - prob_samme))
@pytest.mark.parametrize('loss', ['linear', 'square', 'exponential'])
def test_diabetes(loss):
# Check consistency on dataset diabetes.
reg = AdaBoostRegressor(loss=loss, random_state=0)
reg.fit(diabetes.data, diabetes.target)
score = reg.score(diabetes.data, diabetes.target)
assert score > 0.6
# Check we used multiple estimators
assert len(reg.estimators_) > 1
# Check for distinct random states (see issue #7408)
assert (len(set(est.random_state for est in reg.estimators_)) ==
len(reg.estimators_))
@pytest.mark.parametrize("algorithm", ["SAMME", "SAMME.R"])
def test_staged_predict(algorithm):
# Check staged predictions.
rng = np.random.RandomState(0)
iris_weights = rng.randint(10, size=iris.target.shape)
diabetes_weights = rng.randint(10, size=diabetes.target.shape)
clf = AdaBoostClassifier(algorithm=algorithm, n_estimators=10)
clf.fit(iris.data, iris.target, sample_weight=iris_weights)
predictions = clf.predict(iris.data)
staged_predictions = [p for p in clf.staged_predict(iris.data)]
proba = clf.predict_proba(iris.data)
staged_probas = [p for p in clf.staged_predict_proba(iris.data)]
score = clf.score(iris.data, iris.target, sample_weight=iris_weights)
staged_scores = [
s for s in clf.staged_score(
iris.data, iris.target, sample_weight=iris_weights)]
assert len(staged_predictions) == 10
assert_array_almost_equal(predictions, staged_predictions[-1])
assert len(staged_probas) == 10
assert_array_almost_equal(proba, staged_probas[-1])
assert len(staged_scores) == 10
assert_array_almost_equal(score, staged_scores[-1])
# AdaBoost regression
clf = AdaBoostRegressor(n_estimators=10, random_state=0)
clf.fit(diabetes.data, diabetes.target, sample_weight=diabetes_weights)
predictions = clf.predict(diabetes.data)
staged_predictions = [p for p in clf.staged_predict(diabetes.data)]
score = clf.score(diabetes.data, diabetes.target,
sample_weight=diabetes_weights)
staged_scores = [
s for s in clf.staged_score(
diabetes.data, diabetes.target, sample_weight=diabetes_weights)]
assert len(staged_predictions) == 10
assert_array_almost_equal(predictions, staged_predictions[-1])
assert len(staged_scores) == 10
assert_array_almost_equal(score, staged_scores[-1])
def test_gridsearch():
# Check that base trees can be grid-searched.
# AdaBoost classification
boost = AdaBoostClassifier(base_estimator=DecisionTreeClassifier())
parameters = {'n_estimators': (1, 2),
'base_estimator__max_depth': (1, 2),
'algorithm': ('SAMME', 'SAMME.R')}
clf = GridSearchCV(boost, parameters)
clf.fit(iris.data, iris.target)
# AdaBoost regression
boost = AdaBoostRegressor(base_estimator=DecisionTreeRegressor(),
random_state=0)
parameters = {'n_estimators': (1, 2),
'base_estimator__max_depth': (1, 2)}
clf = GridSearchCV(boost, parameters)
clf.fit(diabetes.data, diabetes.target)
def test_pickle():
# Check pickability.
import pickle
# Adaboost classifier
for alg in ['SAMME', 'SAMME.R']:
obj = AdaBoostClassifier(algorithm=alg)
obj.fit(iris.data, iris.target)
score = obj.score(iris.data, iris.target)
s = pickle.dumps(obj)
obj2 = pickle.loads(s)
assert type(obj2) == obj.__class__
score2 = obj2.score(iris.data, iris.target)
assert score == score2
# Adaboost regressor
obj = AdaBoostRegressor(random_state=0)
obj.fit(diabetes.data, diabetes.target)
score = obj.score(diabetes.data, diabetes.target)
s = pickle.dumps(obj)
obj2 = pickle.loads(s)
assert type(obj2) == obj.__class__
score2 = obj2.score(diabetes.data, diabetes.target)
assert score == score2
def test_importances():
# Check variable importances.
X, y = datasets.make_classification(n_samples=2000,
n_features=10,
n_informative=3,
n_redundant=0,
n_repeated=0,
shuffle=False,
random_state=1)
for alg in ['SAMME', 'SAMME.R']:
clf = AdaBoostClassifier(algorithm=alg)
clf.fit(X, y)
importances = clf.feature_importances_
assert importances.shape[0] == 10
assert (importances[:3, np.newaxis] >= importances[3:]).all()
def test_error():
# Test that it gives proper exception on deficient input.
assert_raises(ValueError,
AdaBoostClassifier(learning_rate=-1).fit,
X, y_class)
assert_raises(ValueError,
AdaBoostClassifier(algorithm="foo").fit,
X, y_class)
assert_raises(ValueError,
AdaBoostClassifier().fit,
X, y_class, sample_weight=np.asarray([-1]))
def test_base_estimator():
# Test different base estimators.
from sklearn.ensemble import RandomForestClassifier
# XXX doesn't work with y_class because RF doesn't support classes_
# Shouldn't AdaBoost run a LabelBinarizer?
clf = AdaBoostClassifier(RandomForestClassifier())
clf.fit(X, y_regr)
clf = AdaBoostClassifier(SVC(), algorithm="SAMME")
clf.fit(X, y_class)
from sklearn.ensemble import RandomForestRegressor
clf = AdaBoostRegressor(RandomForestRegressor(), random_state=0)
clf.fit(X, y_regr)
clf = AdaBoostRegressor(SVR(), random_state=0)
clf.fit(X, y_regr)
# Check that an empty discrete ensemble fails in fit, not predict.
X_fail = [[1, 1], [1, 1], [1, 1], [1, 1]]
y_fail = ["foo", "bar", 1, 2]
clf = AdaBoostClassifier(SVC(), algorithm="SAMME")
assert_raises_regexp(ValueError, "worse than random",
clf.fit, X_fail, y_fail)
def test_sparse_classification():
# Check classification with sparse input.
class CustomSVC(SVC):
"""SVC variant that records the nature of the training set."""
def fit(self, X, y, sample_weight=None):
"""Modification on fit caries data type for later verification."""
super().fit(X, y, sample_weight=sample_weight)
self.data_type_ = type(X)
return self
X, y = datasets.make_multilabel_classification(n_classes=1, n_samples=15,
n_features=5,
random_state=42)
# Flatten y to a 1d array
y = np.ravel(y)
X_train, X_test, y_train, y_test = train_test_split(X, y, random_state=0)
for sparse_format in [csc_matrix, csr_matrix, lil_matrix, coo_matrix,
dok_matrix]:
X_train_sparse = sparse_format(X_train)
X_test_sparse = sparse_format(X_test)
# Trained on sparse format
sparse_classifier = AdaBoostClassifier(
base_estimator=CustomSVC(probability=True),
random_state=1,
algorithm="SAMME"
).fit(X_train_sparse, y_train)
# Trained on dense format
dense_classifier = AdaBoostClassifier(
base_estimator=CustomSVC(probability=True),
random_state=1,
algorithm="SAMME"
).fit(X_train, y_train)
# predict
sparse_results = sparse_classifier.predict(X_test_sparse)
dense_results = dense_classifier.predict(X_test)
assert_array_equal(sparse_results, dense_results)
# decision_function
sparse_results = sparse_classifier.decision_function(X_test_sparse)
dense_results = dense_classifier.decision_function(X_test)
assert_array_almost_equal(sparse_results, dense_results)
# predict_log_proba
sparse_results = sparse_classifier.predict_log_proba(X_test_sparse)
dense_results = dense_classifier.predict_log_proba(X_test)
assert_array_almost_equal(sparse_results, dense_results)
# predict_proba
sparse_results = sparse_classifier.predict_proba(X_test_sparse)
dense_results = dense_classifier.predict_proba(X_test)
assert_array_almost_equal(sparse_results, dense_results)
# score
sparse_results = sparse_classifier.score(X_test_sparse, y_test)
dense_results = dense_classifier.score(X_test, y_test)
assert_array_almost_equal(sparse_results, dense_results)
# staged_decision_function
sparse_results = sparse_classifier.staged_decision_function(
X_test_sparse)
dense_results = dense_classifier.staged_decision_function(X_test)
for sprase_res, dense_res in zip(sparse_results, dense_results):
assert_array_almost_equal(sprase_res, dense_res)
# staged_predict
sparse_results = sparse_classifier.staged_predict(X_test_sparse)
dense_results = dense_classifier.staged_predict(X_test)
for sprase_res, dense_res in zip(sparse_results, dense_results):
assert_array_equal(sprase_res, dense_res)
# staged_predict_proba
sparse_results = sparse_classifier.staged_predict_proba(X_test_sparse)
dense_results = dense_classifier.staged_predict_proba(X_test)
for sprase_res, dense_res in zip(sparse_results, dense_results):
assert_array_almost_equal(sprase_res, dense_res)
# staged_score
sparse_results = sparse_classifier.staged_score(X_test_sparse,
y_test)
dense_results = dense_classifier.staged_score(X_test, y_test)
for sprase_res, dense_res in zip(sparse_results, dense_results):
assert_array_equal(sprase_res, dense_res)
# Verify sparsity of data is maintained during training
types = [i.data_type_ for i in sparse_classifier.estimators_]
assert all([(t == csc_matrix or t == csr_matrix)
for t in types])
def test_sparse_regression():
# Check regression with sparse input.
class CustomSVR(SVR):
"""SVR variant that records the nature of the training set."""
def fit(self, X, y, sample_weight=None):
"""Modification on fit caries data type for later verification."""
super().fit(X, y, sample_weight=sample_weight)
self.data_type_ = type(X)
return self
X, y = datasets.make_regression(n_samples=15, n_features=50, n_targets=1,
random_state=42)
X_train, X_test, y_train, y_test = train_test_split(X, y, random_state=0)
for sparse_format in [csc_matrix, csr_matrix, lil_matrix, coo_matrix,
dok_matrix]:
X_train_sparse = sparse_format(X_train)
X_test_sparse = sparse_format(X_test)
# Trained on sparse format
sparse_classifier = AdaBoostRegressor(
base_estimator=CustomSVR(),
random_state=1
).fit(X_train_sparse, y_train)
# Trained on dense format
dense_classifier = dense_results = AdaBoostRegressor(
base_estimator=CustomSVR(),
random_state=1
).fit(X_train, y_train)
# predict
sparse_results = sparse_classifier.predict(X_test_sparse)
dense_results = dense_classifier.predict(X_test)
assert_array_almost_equal(sparse_results, dense_results)
# staged_predict
sparse_results = sparse_classifier.staged_predict(X_test_sparse)
dense_results = dense_classifier.staged_predict(X_test)
for sprase_res, dense_res in zip(sparse_results, dense_results):
assert_array_almost_equal(sprase_res, dense_res)
types = [i.data_type_ for i in sparse_classifier.estimators_]
assert all([(t == csc_matrix or t == csr_matrix)
for t in types])
def test_sample_weight_adaboost_regressor():
"""
AdaBoostRegressor should work without sample_weights in the base estimator
The random weighted sampling is done internally in the _boost method in
AdaBoostRegressor.
"""
class DummyEstimator(BaseEstimator):
def fit(self, X, y):
pass
def predict(self, X):
return np.zeros(X.shape[0])
boost = AdaBoostRegressor(DummyEstimator(), n_estimators=3)
boost.fit(X, y_regr)
assert len(boost.estimator_weights_) == len(boost.estimator_errors_)
def test_multidimensional_X():
"""
Check that the AdaBoost estimators can work with n-dimensional
data matrix
"""
rng = np.random.RandomState(0)
X = rng.randn(50, 3, 3)
yc = rng.choice([0, 1], 50)
yr = rng.randn(50)
boost = AdaBoostClassifier(DummyClassifier(strategy='most_frequent'))
boost.fit(X, yc)
boost.predict(X)
boost.predict_proba(X)
boost = AdaBoostRegressor(DummyRegressor())
boost.fit(X, yr)
boost.predict(X)
@pytest.mark.parametrize("algorithm", ['SAMME', 'SAMME.R'])
def test_adaboostclassifier_without_sample_weight(algorithm):
X, y = iris.data, iris.target
base_estimator = NoSampleWeightWrapper(DummyClassifier())
clf = AdaBoostClassifier(
base_estimator=base_estimator, algorithm=algorithm
)
err_msg = ("{} doesn't support sample_weight"
.format(base_estimator.__class__.__name__))
with pytest.raises(ValueError, match=err_msg):
clf.fit(X, y)
def test_adaboostregressor_sample_weight():
# check that giving weight will have an influence on the error computed
# for a weak learner
rng = np.random.RandomState(42)
X = np.linspace(0, 100, num=1000)
y = (.8 * X + 0.2) + (rng.rand(X.shape[0]) * 0.0001)
X = X.reshape(-1, 1)
# add an arbitrary outlier
X[-1] *= 10
y[-1] = 10000
# random_state=0 ensure that the underlying bootstrap will use the outlier
regr_no_outlier = AdaBoostRegressor(
base_estimator=LinearRegression(), n_estimators=1, random_state=0
)
regr_with_weight = clone(regr_no_outlier)
regr_with_outlier = clone(regr_no_outlier)
# fit 3 models:
# - a model containing the outlier
# - a model without the outlier
# - a model containing the outlier but with a null sample-weight
regr_with_outlier.fit(X, y)
regr_no_outlier.fit(X[:-1], y[:-1])
sample_weight = np.ones_like(y)
sample_weight[-1] = 0
regr_with_weight.fit(X, y, sample_weight=sample_weight)
score_with_outlier = regr_with_outlier.score(X[:-1], y[:-1])
score_no_outlier = regr_no_outlier.score(X[:-1], y[:-1])
score_with_weight = regr_with_weight.score(X[:-1], y[:-1])
assert score_with_outlier < score_no_outlier
assert score_with_outlier < score_with_weight
assert score_no_outlier == pytest.approx(score_with_weight)
@pytest.mark.parametrize("algorithm", ["SAMME", "SAMME.R"])
def test_adaboost_consistent_predict(algorithm):
# check that predict_proba and predict give consistent results
# regression test for:
# https://github.com/scikit-learn/scikit-learn/issues/14084
X_train, X_test, y_train, y_test = train_test_split(
*datasets.load_digits(return_X_y=True), random_state=42
)
model = AdaBoostClassifier(algorithm=algorithm, random_state=42)
model.fit(X_train, y_train)
assert_array_equal(
np.argmax(model.predict_proba(X_test), axis=1),
model.predict(X_test)
)
@pytest.mark.parametrize(
'model, X, y',
[(AdaBoostClassifier(), iris.data, iris.target),
(AdaBoostRegressor(), diabetes.data, diabetes.target)]
)
def test_adaboost_negative_weight_error(model, X, y):
sample_weight = np.ones_like(y)
sample_weight[-1] = -10
err_msg = "sample_weight cannot contain negative weight"
with pytest.raises(ValueError, match=err_msg):
model.fit(X, y, sample_weight=sample_weight)