/usr/lib/python3/dist-packages/sklearn/ensemble/tests/test_gradient_boosting.py is in python3-sklearn 0.17.0-4.
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Testing for the gradient boosting module (sklearn.ensemble.gradient_boosting).
"""
import warnings
import numpy as np
from itertools import product
from scipy.sparse import csr_matrix
from scipy.sparse import csc_matrix
from scipy.sparse import coo_matrix
from sklearn import datasets
from sklearn.base import clone
from sklearn.ensemble import GradientBoostingClassifier
from sklearn.ensemble import GradientBoostingRegressor
from sklearn.ensemble.gradient_boosting import ZeroEstimator
from sklearn.metrics import mean_squared_error
from sklearn.utils import check_random_state, tosequence
from sklearn.utils.testing import assert_almost_equal
from sklearn.utils.testing import assert_array_almost_equal
from sklearn.utils.testing import assert_array_equal
from sklearn.utils.testing import assert_equal
from sklearn.utils.testing import assert_greater
from sklearn.utils.testing import assert_less
from sklearn.utils.testing import assert_raises
from sklearn.utils.testing import assert_true
from sklearn.utils.testing import assert_warns
from sklearn.utils.testing import skip_if_32bit
from sklearn.utils.validation import DataConversionWarning
from sklearn.utils.validation import NotFittedError
# toy sample
X = [[-2, -1], [-1, -1], [-1, -2], [1, 1], [1, 2], [2, 1]]
y = [-1, -1, -1, 1, 1, 1]
T = [[-1, -1], [2, 2], [3, 2]]
true_result = [-1, 1, 1]
rng = np.random.RandomState(0)
# also load the boston dataset
# and randomly permute it
boston = datasets.load_boston()
perm = rng.permutation(boston.target.size)
boston.data = boston.data[perm]
boston.target = boston.target[perm]
# also load the iris dataset
# and randomly permute it
iris = datasets.load_iris()
perm = rng.permutation(iris.target.size)
iris.data = iris.data[perm]
iris.target = iris.target[perm]
def check_classification_toy(presort, loss):
# Check classification on a toy dataset.
clf = GradientBoostingClassifier(loss=loss, n_estimators=10,
random_state=1, presort=presort)
assert_raises(ValueError, clf.predict, T)
clf.fit(X, y)
assert_array_equal(clf.predict(T), true_result)
assert_equal(10, len(clf.estimators_))
deviance_decrease = (clf.train_score_[:-1] - clf.train_score_[1:])
assert_true(np.any(deviance_decrease >= 0.0))
leaves = clf.apply(X)
assert_equal(leaves.shape, (6, 10, 1))
def test_classification_toy():
for presort, loss in product(('auto', True, False), ('deviance', 'exponential')):
yield check_classification_toy, presort, loss
def test_parameter_checks():
# Check input parameter validation.
assert_raises(ValueError,
GradientBoostingClassifier(n_estimators=0).fit, X, y)
assert_raises(ValueError,
GradientBoostingClassifier(n_estimators=-1).fit, X, y)
assert_raises(ValueError,
GradientBoostingClassifier(learning_rate=0.0).fit, X, y)
assert_raises(ValueError,
GradientBoostingClassifier(learning_rate=-1.0).fit, X, y)
assert_raises(ValueError,
GradientBoostingClassifier(loss='foobar').fit, X, y)
assert_raises(ValueError,
GradientBoostingClassifier(min_samples_split=0.0).fit, X, y)
assert_raises(ValueError,
GradientBoostingClassifier(min_samples_split=-1.0).fit, X, y)
assert_raises(ValueError,
GradientBoostingClassifier(min_samples_leaf=0).fit, X, y)
assert_raises(ValueError,
GradientBoostingClassifier(min_samples_leaf=-1.).fit, X, y)
assert_raises(ValueError,
GradientBoostingClassifier(min_weight_fraction_leaf=-1.).fit,
X, y)
assert_raises(ValueError,
GradientBoostingClassifier(min_weight_fraction_leaf=0.6).fit,
X, y)
assert_raises(ValueError,
GradientBoostingClassifier(subsample=0.0).fit, X, y)
assert_raises(ValueError,
GradientBoostingClassifier(subsample=1.1).fit, X, y)
assert_raises(ValueError,
GradientBoostingClassifier(subsample=-0.1).fit, X, y)
assert_raises(ValueError,
GradientBoostingClassifier(max_depth=-0.1).fit, X, y)
assert_raises(ValueError,
GradientBoostingClassifier(max_depth=0).fit, X, y)
assert_raises(ValueError,
GradientBoostingClassifier(init={}).fit, X, y)
# test fit before feature importance
assert_raises(ValueError,
lambda: GradientBoostingClassifier().feature_importances_)
# deviance requires ``n_classes >= 2``.
assert_raises(ValueError,
lambda X, y: GradientBoostingClassifier(
loss='deviance').fit(X, y),
X, [0, 0, 0, 0])
def test_loss_function():
assert_raises(ValueError,
GradientBoostingClassifier(loss='ls').fit, X, y)
assert_raises(ValueError,
GradientBoostingClassifier(loss='lad').fit, X, y)
assert_raises(ValueError,
GradientBoostingClassifier(loss='quantile').fit, X, y)
assert_raises(ValueError,
GradientBoostingClassifier(loss='huber').fit, X, y)
assert_raises(ValueError,
GradientBoostingRegressor(loss='deviance').fit, X, y)
assert_raises(ValueError,
GradientBoostingRegressor(loss='exponential').fit, X, y)
def check_classification_synthetic(presort, loss):
# Test GradientBoostingClassifier on synthetic dataset used by
# Hastie et al. in ESLII Example 12.7.
X, y = datasets.make_hastie_10_2(n_samples=12000, random_state=1)
X_train, X_test = X[:2000], X[2000:]
y_train, y_test = y[:2000], y[2000:]
gbrt = GradientBoostingClassifier(n_estimators=100, min_samples_split=1,
max_depth=1, loss=loss,
learning_rate=1.0, random_state=0,
presort=presort)
gbrt.fit(X_train, y_train)
error_rate = (1.0 - gbrt.score(X_test, y_test))
assert_less(error_rate, 0.09)
gbrt = GradientBoostingClassifier(n_estimators=200, min_samples_split=1,
max_depth=1,
learning_rate=1.0, subsample=0.5,
random_state=0,
presort=presort)
gbrt.fit(X_train, y_train)
error_rate = (1.0 - gbrt.score(X_test, y_test))
assert_less(error_rate, 0.08)
def test_classification_synthetic():
for presort, loss in product(('auto', True, False), ('deviance', 'exponential')):
yield check_classification_synthetic, presort, loss
def check_boston(presort, loss, subsample):
# Check consistency on dataset boston house prices with least squares
# and least absolute deviation.
ones = np.ones(len(boston.target))
last_y_pred = None
for sample_weight in None, ones, 2*ones:
clf = GradientBoostingRegressor(n_estimators=100,
loss=loss,
max_depth=4,
subsample=subsample,
min_samples_split=1,
random_state=1,
presort=presort)
assert_raises(ValueError, clf.predict, boston.data)
clf.fit(boston.data, boston.target,
sample_weight=sample_weight)
leaves = clf.apply(boston.data)
assert_equal(leaves.shape, (506, 100))
y_pred = clf.predict(boston.data)
mse = mean_squared_error(boston.target, y_pred)
assert_less(mse, 6.0)
if last_y_pred is not None:
assert_array_almost_equal(last_y_pred, y_pred)
last_y_pred = y_pred
def test_boston():
for presort, loss, subsample in product(('auto', True, False),
('ls', 'lad', 'huber'),
(1.0, 0.5)):
yield check_boston, presort, loss, subsample
def check_iris(presort, subsample, sample_weight):
# Check consistency on dataset iris.
clf = GradientBoostingClassifier(n_estimators=100,
loss='deviance',
random_state=1,
subsample=subsample,
presort=presort)
clf.fit(iris.data, iris.target, sample_weight=sample_weight)
score = clf.score(iris.data, iris.target)
assert_greater(score, 0.9)
leaves = clf.apply(iris.data)
assert_equal(leaves.shape, (150, 100, 3))
def test_iris():
ones = np.ones(len(iris.target))
for presort, subsample, sample_weight in product(('auto', True, False),
(1.0, 0.5),
(None, ones)):
yield check_iris, presort, subsample, sample_weight
def test_regression_synthetic():
# Test on synthetic regression datasets used in Leo Breiman,
# `Bagging Predictors?. Machine Learning 24(2): 123-140 (1996).
random_state = check_random_state(1)
regression_params = {'n_estimators': 100, 'max_depth': 4,
'min_samples_split': 1, 'learning_rate': 0.1,
'loss': 'ls'}
# Friedman1
X, y = datasets.make_friedman1(n_samples=1200,
random_state=random_state,
noise=1.0)
X_train, y_train = X[:200], y[:200]
X_test, y_test = X[200:], y[200:]
for presort in True, False:
clf = GradientBoostingRegressor(presort=presort)
clf.fit(X_train, y_train)
mse = mean_squared_error(y_test, clf.predict(X_test))
assert_less(mse, 5.0)
# Friedman2
X, y = datasets.make_friedman2(n_samples=1200, random_state=random_state)
X_train, y_train = X[:200], y[:200]
X_test, y_test = X[200:], y[200:]
for presort in True, False:
regression_params['presort'] = presort
clf = GradientBoostingRegressor(**regression_params)
clf.fit(X_train, y_train)
mse = mean_squared_error(y_test, clf.predict(X_test))
assert_less(mse, 1700.0)
# Friedman3
X, y = datasets.make_friedman3(n_samples=1200, random_state=random_state)
X_train, y_train = X[:200], y[:200]
X_test, y_test = X[200:], y[200:]
for presort in True, False:
regression_params['presort'] = presort
clf = GradientBoostingRegressor(**regression_params)
clf.fit(X_train, y_train)
mse = mean_squared_error(y_test, clf.predict(X_test))
assert_less(mse, 0.015)
def test_feature_importances():
X = np.array(boston.data, dtype=np.float32)
y = np.array(boston.target, dtype=np.float32)
for presort in True, False:
clf = GradientBoostingRegressor(n_estimators=100, max_depth=5,
min_samples_split=1, random_state=1,
presort=presort)
clf.fit(X, y)
assert_true(hasattr(clf, 'feature_importances_'))
# XXX: Remove this test in 0.19 after transform support to estimators
# is removed.
X_new = assert_warns(
DeprecationWarning, clf.transform, X, threshold="mean")
assert_less(X_new.shape[1], X.shape[1])
feature_mask = (
clf.feature_importances_ > clf.feature_importances_.mean())
assert_array_almost_equal(X_new, X[:, feature_mask])
def test_probability_log():
# Predict probabilities.
clf = GradientBoostingClassifier(n_estimators=100, random_state=1)
assert_raises(ValueError, clf.predict_proba, T)
clf.fit(X, y)
assert_array_equal(clf.predict(T), true_result)
# check if probabilities are in [0, 1].
y_proba = clf.predict_proba(T)
assert_true(np.all(y_proba >= 0.0))
assert_true(np.all(y_proba <= 1.0))
# derive predictions from probabilities
y_pred = clf.classes_.take(y_proba.argmax(axis=1), axis=0)
assert_array_equal(y_pred, true_result)
def test_check_inputs():
# Test input checks (shape and type of X and y).
clf = GradientBoostingClassifier(n_estimators=100, random_state=1)
assert_raises(ValueError, clf.fit, X, y + [0, 1])
clf = GradientBoostingClassifier(n_estimators=100, random_state=1)
assert_raises(ValueError, clf.fit, X, y,
sample_weight=([1] * len(y)) + [0, 1])
def test_check_inputs_predict():
# X has wrong shape
clf = GradientBoostingClassifier(n_estimators=100, random_state=1)
clf.fit(X, y)
x = np.array([1.0, 2.0])[:, np.newaxis]
assert_raises(ValueError, clf.predict, x)
x = np.array([[]])
assert_raises(ValueError, clf.predict, x)
x = np.array([1.0, 2.0, 3.0])[:, np.newaxis]
assert_raises(ValueError, clf.predict, x)
clf = GradientBoostingRegressor(n_estimators=100, random_state=1)
clf.fit(X, rng.rand(len(X)))
x = np.array([1.0, 2.0])[:, np.newaxis]
assert_raises(ValueError, clf.predict, x)
x = np.array([[]])
assert_raises(ValueError, clf.predict, x)
x = np.array([1.0, 2.0, 3.0])[:, np.newaxis]
assert_raises(ValueError, clf.predict, x)
def test_check_max_features():
# test if max_features is valid.
clf = GradientBoostingRegressor(n_estimators=100, random_state=1,
max_features=0)
assert_raises(ValueError, clf.fit, X, y)
clf = GradientBoostingRegressor(n_estimators=100, random_state=1,
max_features=(len(X[0]) + 1))
assert_raises(ValueError, clf.fit, X, y)
clf = GradientBoostingRegressor(n_estimators=100, random_state=1,
max_features=-0.1)
assert_raises(ValueError, clf.fit, X, y)
def test_max_feature_regression():
# Test to make sure random state is set properly.
X, y = datasets.make_hastie_10_2(n_samples=12000, random_state=1)
X_train, X_test = X[:2000], X[2000:]
y_train, y_test = y[:2000], y[2000:]
gbrt = GradientBoostingClassifier(n_estimators=100, min_samples_split=5,
max_depth=2, learning_rate=.1,
max_features=2, random_state=1)
gbrt.fit(X_train, y_train)
deviance = gbrt.loss_(y_test, gbrt.decision_function(X_test))
assert_true(deviance < 0.5, "GB failed with deviance %.4f" % deviance)
def test_max_feature_auto():
# Test if max features is set properly for floats and str.
X, y = datasets.make_hastie_10_2(n_samples=12000, random_state=1)
_, n_features = X.shape
X_train = X[:2000]
y_train = y[:2000]
gbrt = GradientBoostingClassifier(n_estimators=1, max_features='auto')
gbrt.fit(X_train, y_train)
assert_equal(gbrt.max_features_, int(np.sqrt(n_features)))
gbrt = GradientBoostingRegressor(n_estimators=1, max_features='auto')
gbrt.fit(X_train, y_train)
assert_equal(gbrt.max_features_, n_features)
gbrt = GradientBoostingRegressor(n_estimators=1, max_features=0.3)
gbrt.fit(X_train, y_train)
assert_equal(gbrt.max_features_, int(n_features * 0.3))
gbrt = GradientBoostingRegressor(n_estimators=1, max_features='sqrt')
gbrt.fit(X_train, y_train)
assert_equal(gbrt.max_features_, int(np.sqrt(n_features)))
gbrt = GradientBoostingRegressor(n_estimators=1, max_features='log2')
gbrt.fit(X_train, y_train)
assert_equal(gbrt.max_features_, int(np.log2(n_features)))
gbrt = GradientBoostingRegressor(n_estimators=1,
max_features=0.01 / X.shape[1])
gbrt.fit(X_train, y_train)
assert_equal(gbrt.max_features_, 1)
def test_staged_predict():
# Test whether staged decision function eventually gives
# the same prediction.
X, y = datasets.make_friedman1(n_samples=1200,
random_state=1, noise=1.0)
X_train, y_train = X[:200], y[:200]
X_test = X[200:]
clf = GradientBoostingRegressor()
# test raise ValueError if not fitted
assert_raises(ValueError, lambda X: np.fromiter(
clf.staged_predict(X), dtype=np.float64), X_test)
clf.fit(X_train, y_train)
y_pred = clf.predict(X_test)
# test if prediction for last stage equals ``predict``
for y in clf.staged_predict(X_test):
assert_equal(y.shape, y_pred.shape)
assert_array_equal(y_pred, y)
def test_staged_predict_proba():
# Test whether staged predict proba eventually gives
# the same prediction.
X, y = datasets.make_hastie_10_2(n_samples=1200,
random_state=1)
X_train, y_train = X[:200], y[:200]
X_test, y_test = X[200:], y[200:]
clf = GradientBoostingClassifier(n_estimators=20)
# test raise NotFittedError if not fitted
assert_raises(NotFittedError, lambda X: np.fromiter(
clf.staged_predict_proba(X), dtype=np.float64), X_test)
clf.fit(X_train, y_train)
# test if prediction for last stage equals ``predict``
for y_pred in clf.staged_predict(X_test):
assert_equal(y_test.shape, y_pred.shape)
assert_array_equal(clf.predict(X_test), y_pred)
# test if prediction for last stage equals ``predict_proba``
for staged_proba in clf.staged_predict_proba(X_test):
assert_equal(y_test.shape[0], staged_proba.shape[0])
assert_equal(2, staged_proba.shape[1])
assert_array_equal(clf.predict_proba(X_test), staged_proba)
def test_staged_functions_defensive():
# test that staged_functions make defensive copies
rng = np.random.RandomState(0)
X = rng.uniform(size=(10, 3))
y = (4 * X[:, 0]).astype(np.int) + 1 # don't predict zeros
for estimator in [GradientBoostingRegressor(),
GradientBoostingClassifier()]:
estimator.fit(X, y)
for func in ['predict', 'decision_function', 'predict_proba']:
staged_func = getattr(estimator, "staged_" + func, None)
if staged_func is None:
# regressor has no staged_predict_proba
continue
with warnings.catch_warnings(record=True):
staged_result = list(staged_func(X))
staged_result[1][:] = 0
assert_true(np.all(staged_result[0] != 0))
def test_serialization():
# Check model serialization.
clf = GradientBoostingClassifier(n_estimators=100, random_state=1)
clf.fit(X, y)
assert_array_equal(clf.predict(T), true_result)
assert_equal(100, len(clf.estimators_))
try:
import cPickle as pickle
except ImportError:
import pickle
serialized_clf = pickle.dumps(clf, protocol=pickle.HIGHEST_PROTOCOL)
clf = None
clf = pickle.loads(serialized_clf)
assert_array_equal(clf.predict(T), true_result)
assert_equal(100, len(clf.estimators_))
def test_degenerate_targets():
# Check if we can fit even though all targets are equal.
clf = GradientBoostingClassifier(n_estimators=100, random_state=1)
# classifier should raise exception
assert_raises(ValueError, clf.fit, X, np.ones(len(X)))
clf = GradientBoostingRegressor(n_estimators=100, random_state=1)
clf.fit(X, np.ones(len(X)))
clf.predict([rng.rand(2)])
assert_array_equal(np.ones((1,), dtype=np.float64),
clf.predict([rng.rand(2)]))
def test_quantile_loss():
# Check if quantile loss with alpha=0.5 equals lad.
clf_quantile = GradientBoostingRegressor(n_estimators=100, loss='quantile',
max_depth=4, alpha=0.5,
random_state=7)
clf_quantile.fit(boston.data, boston.target)
y_quantile = clf_quantile.predict(boston.data)
clf_lad = GradientBoostingRegressor(n_estimators=100, loss='lad',
max_depth=4, random_state=7)
clf_lad.fit(boston.data, boston.target)
y_lad = clf_lad.predict(boston.data)
assert_array_almost_equal(y_quantile, y_lad, decimal=4)
def test_symbol_labels():
# Test with non-integer class labels.
clf = GradientBoostingClassifier(n_estimators=100, random_state=1)
symbol_y = tosequence(map(str, y))
clf.fit(X, symbol_y)
assert_array_equal(clf.predict(T), tosequence(map(str, true_result)))
assert_equal(100, len(clf.estimators_))
def test_float_class_labels():
# Test with float class labels.
clf = GradientBoostingClassifier(n_estimators=100, random_state=1)
float_y = np.asarray(y, dtype=np.float32)
clf.fit(X, float_y)
assert_array_equal(clf.predict(T),
np.asarray(true_result, dtype=np.float32))
assert_equal(100, len(clf.estimators_))
def test_shape_y():
# Test with float class labels.
clf = GradientBoostingClassifier(n_estimators=100, random_state=1)
y_ = np.asarray(y, dtype=np.int32)
y_ = y_[:, np.newaxis]
# This will raise a DataConversionWarning that we want to
# "always" raise, elsewhere the warnings gets ignored in the
# later tests, and the tests that check for this warning fail
assert_warns(DataConversionWarning, clf.fit, X, y_)
assert_array_equal(clf.predict(T), true_result)
assert_equal(100, len(clf.estimators_))
def test_mem_layout():
# Test with different memory layouts of X and y
X_ = np.asfortranarray(X)
clf = GradientBoostingClassifier(n_estimators=100, random_state=1)
clf.fit(X_, y)
assert_array_equal(clf.predict(T), true_result)
assert_equal(100, len(clf.estimators_))
X_ = np.ascontiguousarray(X)
clf = GradientBoostingClassifier(n_estimators=100, random_state=1)
clf.fit(X_, y)
assert_array_equal(clf.predict(T), true_result)
assert_equal(100, len(clf.estimators_))
y_ = np.asarray(y, dtype=np.int32)
y_ = np.ascontiguousarray(y_)
clf = GradientBoostingClassifier(n_estimators=100, random_state=1)
clf.fit(X, y_)
assert_array_equal(clf.predict(T), true_result)
assert_equal(100, len(clf.estimators_))
y_ = np.asarray(y, dtype=np.int32)
y_ = np.asfortranarray(y_)
clf = GradientBoostingClassifier(n_estimators=100, random_state=1)
clf.fit(X, y_)
assert_array_equal(clf.predict(T), true_result)
assert_equal(100, len(clf.estimators_))
def test_oob_improvement():
# Test if oob improvement has correct shape and regression test.
clf = GradientBoostingClassifier(n_estimators=100, random_state=1,
subsample=0.5)
clf.fit(X, y)
assert_equal(clf.oob_improvement_.shape[0], 100)
# hard-coded regression test - change if modification in OOB computation
assert_array_almost_equal(clf.oob_improvement_[:5],
np.array([0.19, 0.15, 0.12, -0.12, -0.11]),
decimal=2)
def test_oob_improvement_raise():
# Test if oob improvement has correct shape.
clf = GradientBoostingClassifier(n_estimators=100, random_state=1,
subsample=1.0)
clf.fit(X, y)
assert_raises(AttributeError, lambda: clf.oob_improvement_)
def test_oob_multilcass_iris():
# Check OOB improvement on multi-class dataset.
clf = GradientBoostingClassifier(n_estimators=100, loss='deviance',
random_state=1, subsample=0.5)
clf.fit(iris.data, iris.target)
score = clf.score(iris.data, iris.target)
assert_greater(score, 0.9)
assert_equal(clf.oob_improvement_.shape[0], clf.n_estimators)
# hard-coded regression test - change if modification in OOB computation
# FIXME: the following snippet does not yield the same results on 32 bits
# assert_array_almost_equal(clf.oob_improvement_[:5],
# np.array([12.68, 10.45, 8.18, 6.43, 5.13]),
# decimal=2)
def test_verbose_output():
# Check verbose=1 does not cause error.
from sklearn.externals.six.moves import cStringIO as StringIO
import sys
old_stdout = sys.stdout
sys.stdout = StringIO()
clf = GradientBoostingClassifier(n_estimators=100, random_state=1,
verbose=1, subsample=0.8)
clf.fit(X, y)
verbose_output = sys.stdout
sys.stdout = old_stdout
# check output
verbose_output.seek(0)
header = verbose_output.readline().rstrip()
# with OOB
true_header = ' '.join(['%10s'] + ['%16s'] * 3) % (
'Iter', 'Train Loss', 'OOB Improve', 'Remaining Time')
assert_equal(true_header, header)
n_lines = sum(1 for l in verbose_output.readlines())
# one for 1-10 and then 9 for 20-100
assert_equal(10 + 9, n_lines)
def test_more_verbose_output():
# Check verbose=2 does not cause error.
from sklearn.externals.six.moves import cStringIO as StringIO
import sys
old_stdout = sys.stdout
sys.stdout = StringIO()
clf = GradientBoostingClassifier(n_estimators=100, random_state=1,
verbose=2)
clf.fit(X, y)
verbose_output = sys.stdout
sys.stdout = old_stdout
# check output
verbose_output.seek(0)
header = verbose_output.readline().rstrip()
# no OOB
true_header = ' '.join(['%10s'] + ['%16s'] * 2) % (
'Iter', 'Train Loss', 'Remaining Time')
assert_equal(true_header, header)
n_lines = sum(1 for l in verbose_output.readlines())
# 100 lines for n_estimators==100
assert_equal(100, n_lines)
def test_warm_start():
# Test if warm start equals fit.
X, y = datasets.make_hastie_10_2(n_samples=100, random_state=1)
for Cls in [GradientBoostingRegressor, GradientBoostingClassifier]:
est = Cls(n_estimators=200, max_depth=1)
est.fit(X, y)
est_ws = Cls(n_estimators=100, max_depth=1, warm_start=True)
est_ws.fit(X, y)
est_ws.set_params(n_estimators=200)
est_ws.fit(X, y)
assert_array_almost_equal(est_ws.predict(X), est.predict(X))
def test_warm_start_n_estimators():
# Test if warm start equals fit - set n_estimators.
X, y = datasets.make_hastie_10_2(n_samples=100, random_state=1)
for Cls in [GradientBoostingRegressor, GradientBoostingClassifier]:
est = Cls(n_estimators=300, max_depth=1)
est.fit(X, y)
est_ws = Cls(n_estimators=100, max_depth=1, warm_start=True)
est_ws.fit(X, y)
est_ws.set_params(n_estimators=300)
est_ws.fit(X, y)
assert_array_almost_equal(est_ws.predict(X), est.predict(X))
def test_warm_start_max_depth():
# Test if possible to fit trees of different depth in ensemble.
X, y = datasets.make_hastie_10_2(n_samples=100, random_state=1)
for Cls in [GradientBoostingRegressor, GradientBoostingClassifier]:
est = Cls(n_estimators=100, max_depth=1, warm_start=True)
est.fit(X, y)
est.set_params(n_estimators=110, max_depth=2)
est.fit(X, y)
# last 10 trees have different depth
assert_equal(est.estimators_[0, 0].max_depth, 1)
for i in range(1, 11):
assert_equal(est.estimators_[-i, 0].max_depth, 2)
def test_warm_start_clear():
# Test if fit clears state.
X, y = datasets.make_hastie_10_2(n_samples=100, random_state=1)
for Cls in [GradientBoostingRegressor, GradientBoostingClassifier]:
est = Cls(n_estimators=100, max_depth=1)
est.fit(X, y)
est_2 = Cls(n_estimators=100, max_depth=1, warm_start=True)
est_2.fit(X, y) # inits state
est_2.set_params(warm_start=False)
est_2.fit(X, y) # clears old state and equals est
assert_array_almost_equal(est_2.predict(X), est.predict(X))
def test_warm_start_zero_n_estimators():
# Test if warm start with zero n_estimators raises error
X, y = datasets.make_hastie_10_2(n_samples=100, random_state=1)
for Cls in [GradientBoostingRegressor, GradientBoostingClassifier]:
est = Cls(n_estimators=100, max_depth=1, warm_start=True)
est.fit(X, y)
est.set_params(n_estimators=0)
assert_raises(ValueError, est.fit, X, y)
def test_warm_start_smaller_n_estimators():
# Test if warm start with smaller n_estimators raises error
X, y = datasets.make_hastie_10_2(n_samples=100, random_state=1)
for Cls in [GradientBoostingRegressor, GradientBoostingClassifier]:
est = Cls(n_estimators=100, max_depth=1, warm_start=True)
est.fit(X, y)
est.set_params(n_estimators=99)
assert_raises(ValueError, est.fit, X, y)
def test_warm_start_equal_n_estimators():
# Test if warm start with equal n_estimators does nothing
X, y = datasets.make_hastie_10_2(n_samples=100, random_state=1)
for Cls in [GradientBoostingRegressor, GradientBoostingClassifier]:
est = Cls(n_estimators=100, max_depth=1)
est.fit(X, y)
est2 = clone(est)
est2.set_params(n_estimators=est.n_estimators, warm_start=True)
est2.fit(X, y)
assert_array_almost_equal(est2.predict(X), est.predict(X))
def test_warm_start_oob_switch():
# Test if oob can be turned on during warm start.
X, y = datasets.make_hastie_10_2(n_samples=100, random_state=1)
for Cls in [GradientBoostingRegressor, GradientBoostingClassifier]:
est = Cls(n_estimators=100, max_depth=1, warm_start=True)
est.fit(X, y)
est.set_params(n_estimators=110, subsample=0.5)
est.fit(X, y)
assert_array_equal(est.oob_improvement_[:100], np.zeros(100))
# the last 10 are not zeros
assert_array_equal(est.oob_improvement_[-10:] == 0.0,
np.zeros(10, dtype=np.bool))
def test_warm_start_oob():
# Test if warm start OOB equals fit.
X, y = datasets.make_hastie_10_2(n_samples=100, random_state=1)
for Cls in [GradientBoostingRegressor, GradientBoostingClassifier]:
est = Cls(n_estimators=200, max_depth=1, subsample=0.5,
random_state=1)
est.fit(X, y)
est_ws = Cls(n_estimators=100, max_depth=1, subsample=0.5,
random_state=1, warm_start=True)
est_ws.fit(X, y)
est_ws.set_params(n_estimators=200)
est_ws.fit(X, y)
assert_array_almost_equal(est_ws.oob_improvement_[:100],
est.oob_improvement_[:100])
def early_stopping_monitor(i, est, locals):
"""Returns True on the 10th iteration. """
if i == 9:
return True
else:
return False
def test_monitor_early_stopping():
# Test if monitor return value works.
X, y = datasets.make_hastie_10_2(n_samples=100, random_state=1)
for Cls in [GradientBoostingRegressor, GradientBoostingClassifier]:
est = Cls(n_estimators=20, max_depth=1, random_state=1, subsample=0.5)
est.fit(X, y, monitor=early_stopping_monitor)
assert_equal(est.n_estimators, 20) # this is not altered
assert_equal(est.estimators_.shape[0], 10)
assert_equal(est.train_score_.shape[0], 10)
assert_equal(est.oob_improvement_.shape[0], 10)
# try refit
est.set_params(n_estimators=30)
est.fit(X, y)
assert_equal(est.n_estimators, 30)
assert_equal(est.estimators_.shape[0], 30)
assert_equal(est.train_score_.shape[0], 30)
est = Cls(n_estimators=20, max_depth=1, random_state=1, subsample=0.5,
warm_start=True)
est.fit(X, y, monitor=early_stopping_monitor)
assert_equal(est.n_estimators, 20)
assert_equal(est.estimators_.shape[0], 10)
assert_equal(est.train_score_.shape[0], 10)
assert_equal(est.oob_improvement_.shape[0], 10)
# try refit
est.set_params(n_estimators=30, warm_start=False)
est.fit(X, y)
assert_equal(est.n_estimators, 30)
assert_equal(est.train_score_.shape[0], 30)
assert_equal(est.estimators_.shape[0], 30)
assert_equal(est.oob_improvement_.shape[0], 30)
def test_complete_classification():
# Test greedy trees with max_depth + 1 leafs.
from sklearn.tree._tree import TREE_LEAF
X, y = datasets.make_hastie_10_2(n_samples=100, random_state=1)
k = 4
est = GradientBoostingClassifier(n_estimators=20, max_depth=None,
random_state=1, max_leaf_nodes=k + 1)
est.fit(X, y)
tree = est.estimators_[0, 0].tree_
assert_equal(tree.max_depth, k)
assert_equal(tree.children_left[tree.children_left == TREE_LEAF].shape[0],
k + 1)
def test_complete_regression():
# Test greedy trees with max_depth + 1 leafs.
from sklearn.tree._tree import TREE_LEAF
k = 4
est = GradientBoostingRegressor(n_estimators=20, max_depth=None,
random_state=1, max_leaf_nodes=k + 1)
est.fit(boston.data, boston.target)
tree = est.estimators_[-1, 0].tree_
assert_equal(tree.children_left[tree.children_left == TREE_LEAF].shape[0],
k + 1)
def test_zero_estimator_reg():
# Test if ZeroEstimator works for regression.
est = GradientBoostingRegressor(n_estimators=20, max_depth=1,
random_state=1, init=ZeroEstimator())
est.fit(boston.data, boston.target)
y_pred = est.predict(boston.data)
mse = mean_squared_error(boston.target, y_pred)
assert_almost_equal(mse, 33.0, decimal=0)
est = GradientBoostingRegressor(n_estimators=20, max_depth=1,
random_state=1, init='zero')
est.fit(boston.data, boston.target)
y_pred = est.predict(boston.data)
mse = mean_squared_error(boston.target, y_pred)
assert_almost_equal(mse, 33.0, decimal=0)
est = GradientBoostingRegressor(n_estimators=20, max_depth=1,
random_state=1, init='foobar')
assert_raises(ValueError, est.fit, boston.data, boston.target)
def test_zero_estimator_clf():
# Test if ZeroEstimator works for classification.
X = iris.data
y = np.array(iris.target)
est = GradientBoostingClassifier(n_estimators=20, max_depth=1,
random_state=1, init=ZeroEstimator())
est.fit(X, y)
assert_greater(est.score(X, y), 0.96)
est = GradientBoostingClassifier(n_estimators=20, max_depth=1,
random_state=1, init='zero')
est.fit(X, y)
assert_greater(est.score(X, y), 0.96)
# binary clf
mask = y != 0
y[mask] = 1
y[~mask] = 0
est = GradientBoostingClassifier(n_estimators=20, max_depth=1,
random_state=1, init='zero')
est.fit(X, y)
assert_greater(est.score(X, y), 0.96)
est = GradientBoostingClassifier(n_estimators=20, max_depth=1,
random_state=1, init='foobar')
assert_raises(ValueError, est.fit, X, y)
def test_max_leaf_nodes_max_depth():
# Test preceedence of max_leaf_nodes over max_depth.
X, y = datasets.make_hastie_10_2(n_samples=100, random_state=1)
all_estimators = [GradientBoostingRegressor,
GradientBoostingClassifier]
k = 4
for GBEstimator in all_estimators:
est = GBEstimator(max_depth=1, max_leaf_nodes=k).fit(X, y)
tree = est.estimators_[0, 0].tree_
assert_greater(tree.max_depth, 1)
est = GBEstimator(max_depth=1).fit(X, y)
tree = est.estimators_[0, 0].tree_
assert_equal(tree.max_depth, 1)
def test_warm_start_wo_nestimators_change():
# Test if warm_start does nothing if n_estimators is not changed.
# Regression test for #3513.
clf = GradientBoostingClassifier(n_estimators=10, warm_start=True)
clf.fit([[0, 1], [2, 3]], [0, 1])
assert_equal(clf.estimators_.shape[0], 10)
clf.fit([[0, 1], [2, 3]], [0, 1])
assert_equal(clf.estimators_.shape[0], 10)
def test_probability_exponential():
# Predict probabilities.
clf = GradientBoostingClassifier(loss='exponential',
n_estimators=100, random_state=1)
assert_raises(ValueError, clf.predict_proba, T)
clf.fit(X, y)
assert_array_equal(clf.predict(T), true_result)
# check if probabilities are in [0, 1].
y_proba = clf.predict_proba(T)
assert_true(np.all(y_proba >= 0.0))
assert_true(np.all(y_proba <= 1.0))
score = clf.decision_function(T).ravel()
assert_array_almost_equal(y_proba[:, 1],
1.0 / (1.0 + np.exp(-2 * score)))
# derive predictions from probabilities
y_pred = clf.classes_.take(y_proba.argmax(axis=1), axis=0)
assert_array_equal(y_pred, true_result)
def test_non_uniform_weights_toy_edge_case_reg():
X = [[1, 0],
[1, 0],
[1, 0],
[0, 1]]
y = [0, 0, 1, 0]
# ignore the first 2 training samples by setting their weight to 0
sample_weight = [0, 0, 1, 1]
for loss in ('huber', 'ls', 'lad', 'quantile'):
gb = GradientBoostingRegressor(learning_rate=1.0, n_estimators=2, loss=loss)
gb.fit(X, y, sample_weight=sample_weight)
assert_greater(gb.predict([[1, 0]])[0], 0.5)
def test_non_uniform_weights_toy_edge_case_clf():
X = [[1, 0],
[1, 0],
[1, 0],
[0, 1]]
y = [0, 0, 1, 0]
# ignore the first 2 training samples by setting their weight to 0
sample_weight = [0, 0, 1, 1]
for loss in ('deviance', 'exponential'):
gb = GradientBoostingClassifier(n_estimators=5)
gb.fit(X, y, sample_weight=sample_weight)
assert_array_equal(gb.predict([[1, 0]]), [1])
def check_sparse_input(EstimatorClass, X, X_sparse, y):
dense = EstimatorClass(n_estimators=10, random_state=0, max_depth=2).fit(X, y)
sparse = EstimatorClass(n_estimators=10, random_state=0, max_depth=2,
presort=False).fit(X_sparse, y)
auto = EstimatorClass(n_estimators=10, random_state=0, max_depth=2,
presort='auto').fit(X_sparse, y)
assert_array_almost_equal(sparse.apply(X), dense.apply(X))
assert_array_almost_equal(sparse.predict(X), dense.predict(X))
assert_array_almost_equal(sparse.feature_importances_,
dense.feature_importances_)
assert_array_almost_equal(sparse.apply(X), auto.apply(X))
assert_array_almost_equal(sparse.predict(X), auto.predict(X))
assert_array_almost_equal(sparse.feature_importances_,
auto.feature_importances_)
if isinstance(EstimatorClass, GradientBoostingClassifier):
assert_array_almost_equal(sparse.predict_proba(X),
dense.predict_proba(X))
assert_array_almost_equal(sparse.predict_log_proba(X),
dense.predict_log_proba(X))
assert_array_almost_equal(sparse.predict_proba(X),
auto.predict_proba(X))
assert_array_almost_equal(sparse.predict_log_proba(X),
auto.predict_log_proba(X))
@skip_if_32bit
def test_sparse_input():
ests = (GradientBoostingClassifier, GradientBoostingRegressor)
sparse_matrices = (csr_matrix, csc_matrix, coo_matrix)
y, X = datasets.make_multilabel_classification(random_state=0,
n_samples=50,
n_features=1,
n_classes=20)
y = y[:, 0]
for EstimatorClass, sparse_matrix in product(ests, sparse_matrices):
yield check_sparse_input, EstimatorClass, X, sparse_matrix(X), y
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