def test_kernel_clone_after_set_params(kernel):
# This test is to verify that using set_params does not
# break clone on kernels.
# This used to break because in kernels such as the RBF, non-trivial
# logic that modified the length scale used to be in the constructor
# See https://github.com/scikit-learn/scikit-learn/issues/6961
# for more details.
bounds = (1e-5, 1e5)
kernel_cloned = clone(kernel)
params = kernel.get_params()
# RationalQuadratic kernel is isotropic.
isotropic_kernels = (ExpSineSquared, RationalQuadratic)
if 'length_scale' in params and not isinstance(kernel, isotropic_kernels):
length_scale = params['length_scale']
if np.iterable(length_scale):
params['length_scale'] = length_scale[0]
params['length_scale_bounds'] = bounds
else:
params['length_scale'] = [length_scale] * 2
params['length_scale_bounds'] = bounds * 2
kernel_cloned.set_params(**params)
kernel_cloned_clone = clone(kernel_cloned)
assert (kernel_cloned_clone.get_params() == kernel_cloned.get_params())
assert id(kernel_cloned_clone) != id(kernel_cloned)
check_hyperparameters_equal(kernel_cloned, kernel_cloned_clone)
def test_clone_empty_array():
# Regression test for cloning estimators with empty arrays
clf = MyEstimator(empty=np.array([]))
clf2 = clone(clf)
assert_array_equal(clf.empty, clf2.empty)
clf = MyEstimator(empty=sp.csr_matrix(np.array([[0]])))
clf2 = clone(clf)
assert_array_equal(clf.empty.data, clf2.empty.data)
def test_unit_weights_vs_no_weights():
# not passing any sample weights should be equivalent
# to all weights equal to one
sample_weight = np.ones(n_samples)
for estimator in [
KMeans(n_clusters=n_clusters, random_state=42),
MiniBatchKMeans(n_clusters=n_clusters, random_state=42)
]:
est_1 = clone(estimator).fit(X)
est_2 = clone(estimator).fit(X, sample_weight=sample_weight)
assert_almost_equal(v_measure_score(est_1.labels_, est_2.labels_), 1.0)
assert_almost_equal(_sort_centers(est_1.cluster_centers_),
_sort_centers(est_2.cluster_centers_))
def test_scaled_weights():
# scaling all sample weights by a common factor
# shouldn't change the result
sample_weight = np.ones(n_samples)
for estimator in [
KMeans(n_clusters=n_clusters, random_state=42),
MiniBatchKMeans(n_clusters=n_clusters, random_state=42)
]:
est_1 = clone(estimator).fit(X)
est_2 = clone(estimator).fit(X, sample_weight=0.5 * sample_weight)
assert_almost_equal(v_measure_score(est_1.labels_, est_2.labels_), 1.0)
assert_almost_equal(_sort_centers(est_1.cluster_centers_),
_sort_centers(est_2.cluster_centers_))
def test_multi_output_classification():
# test if multi_target initializes correctly with base estimator and fit
# assert predictions work as expected for predict, prodict_proba and score
forest = RandomForestClassifier(n_estimators=10, random_state=1)
multi_target_forest = MultiOutputClassifier(forest)
# train the multi_target_forest and also get the predictions.
multi_target_forest.fit(X, y)
predictions = multi_target_forest.predict(X)
assert (n_samples, n_outputs) == predictions.shape
predict_proba = multi_target_forest.predict_proba(X)
assert len(predict_proba) == n_outputs
for class_probabilities in predict_proba:
assert (n_samples, n_classes) == class_probabilities.shape
assert_array_equal(np.argmax(np.dstack(predict_proba), axis=1),
predictions)
# train the forest with each column and assert that predictions are equal
for i in range(3):
forest_ = clone(forest) # create a clone with the same state
forest_.fit(X, y[:, i])
assert list(forest_.predict(X)) == list(predictions[:, i])
assert_array_equal(list(forest_.predict_proba(X)),
list(predict_proba[i]))
def test_multi_output_classification_partial_fit():
# test if multi_target initializes correctly with base estimator and fit
# assert predictions work as expected for predict
sgd_linear_clf = SGDClassifier(loss='log', random_state=1, max_iter=5)
multi_target_linear = MultiOutputClassifier(sgd_linear_clf)
# train the multi_target_linear and also get the predictions.
half_index = X.shape[0] // 2
multi_target_linear.partial_fit(X[:half_index],
y[:half_index],
classes=classes)
first_predictions = multi_target_linear.predict(X)
assert (n_samples, n_outputs) == first_predictions.shape
multi_target_linear.partial_fit(X[half_index:], y[half_index:])
second_predictions = multi_target_linear.predict(X)
assert (n_samples, n_outputs) == second_predictions.shape
# train the linear classification with each column and assert that
# predictions are equal after first partial_fit and second partial_fit
for i in range(3):
# create a clone with the same state
sgd_linear_clf = clone(sgd_linear_clf)
sgd_linear_clf.partial_fit(X[:half_index],
y[:half_index, i],
classes=classes[i])
assert_array_equal(sgd_linear_clf.predict(X), first_predictions[:, i])
sgd_linear_clf.partial_fit(X[half_index:], y[half_index:, i])
assert_array_equal(sgd_linear_clf.predict(X), second_predictions[:, i])
def test_clone_estimator_types():
# Check that clone works for parameters that are types rather than
# instances
clf = MyEstimator(empty=MyEstimator)
clf2 = clone(clf)
assert clf.empty is clf2.empty
def test_clone_pandas_dataframe():
class DummyEstimator(BaseEstimator, TransformerMixin):
"""This is a dummy class for generating numerical features
This feature extractor extracts numerical features from pandas data
frame.
Parameters
----------
df: pandas data frame
The pandas data frame parameter.
Notes
-----
"""
def __init__(self, df=None, scalar_param=1):
self.df = df
self.scalar_param = scalar_param
def fit(self, X, y=None):
pass
def transform(self, X):
pass
# build and clone estimator
d = np.arange(10)
df = MockDataFrame(d)
e = DummyEstimator(df, scalar_param=1)
cloned_e = clone(e)
# the test
assert (e.df == cloned_e.df).values.all()
assert e.scalar_param == cloned_e.scalar_param
def test_clone():
# Tests that clone creates a correct deep copy.
# We create an estimator, make a copy of its original state
# (which, in this case, is the current state of the estimator),
# and check that the obtained copy is a correct deep copy.
from mrex.feature_selection import SelectFpr, f_classif
selector = SelectFpr(f_classif, alpha=0.1)
new_selector = clone(selector)
assert selector is not new_selector
assert selector.get_params() == new_selector.get_params()
selector = SelectFpr(f_classif, alpha=np.zeros((10, 2)))
new_selector = clone(selector)
assert selector is not new_selector
def test_svc_clone_with_callable_kernel():
# create SVM with callable linear kernel, check that results are the same
# as with built-in linear kernel
svm_callable = svm.SVC(kernel=lambda x, y: np.dot(x, y.T),
probability=True,
random_state=0,
decision_function_shape='ovr')
# clone for checking clonability with lambda functions..
svm_cloned = base.clone(svm_callable)
svm_cloned.fit(iris.data, iris.target)
svm_builtin = svm.SVC(kernel='linear',
probability=True,
random_state=0,
decision_function_shape='ovr')
svm_builtin.fit(iris.data, iris.target)
assert_array_almost_equal(svm_cloned.dual_coef_, svm_builtin.dual_coef_)
assert_array_almost_equal(svm_cloned.intercept_, svm_builtin.intercept_)
assert_array_equal(svm_cloned.predict(iris.data),
svm_builtin.predict(iris.data))
assert_array_almost_equal(svm_cloned.predict_proba(iris.data),
svm_builtin.predict_proba(iris.data),
decimal=4)
assert_array_almost_equal(svm_cloned.decision_function(iris.data),
svm_builtin.decision_function(iris.data))
def test_classifier_results():
"""tests if classifier results match target"""
alpha = .1
n_features = 20
n_samples = 10
tol = .01
max_iter = 200
rng = np.random.RandomState(0)
X = rng.normal(size=(n_samples, n_features))
w = rng.normal(size=n_features)
y = np.dot(X, w)
y = np.sign(y)
clf1 = LogisticRegression(solver='sag',
C=1. / alpha / n_samples,
max_iter=max_iter,
tol=tol,
random_state=77)
clf2 = clone(clf1)
clf1.fit(X, y)
clf2.fit(sp.csr_matrix(X), y)
pred1 = clf1.predict(X)
pred2 = clf2.predict(X)
assert_almost_equal(pred1, y, decimal=12)
assert_almost_equal(pred2, y, decimal=12)
def test_transform_target_regressor_2d_transformer(X, y):
# Check consistency with transformer accepting only 2D array and a 1D/2D y
# array.
transformer = StandardScaler()
regr = TransformedTargetRegressor(regressor=LinearRegression(),
transformer=transformer)
y_pred = regr.fit(X, y).predict(X)
assert y.shape == y_pred.shape
# consistency forward transform
if y.ndim == 1: # create a 2D array and squeeze results
y_tran = regr.transformer_.transform(y.reshape(-1, 1)).squeeze()
else:
y_tran = regr.transformer_.transform(y)
_check_standard_scaled(y, y_tran)
assert y.shape == y_pred.shape
# consistency inverse transform
assert_allclose(y, regr.transformer_.inverse_transform(
y_tran).squeeze())
# consistency of the regressor
lr = LinearRegression()
transformer2 = clone(transformer)
if y.ndim == 1: # create a 2D array and squeeze results
lr.fit(X, transformer2.fit_transform(y.reshape(-1, 1)).squeeze())
else:
lr.fit(X, transformer2.fit_transform(y))
y_lr_pred = lr.predict(X)
assert_allclose(y_pred, transformer2.inverse_transform(y_lr_pred))
assert_allclose(regr.regressor_.coef_, lr.coef_)
def test_transform_target_regressor_1d_transformer(X, y):
# All transformer in scikit-learn expect 2D data. FunctionTransformer with
# validate=False lift this constraint without checking that the input is a
# 2D vector. We check the consistency of the data shape using a 1D and 2D y
# array.
transformer = FunctionTransformer(func=lambda x: x + 1,
inverse_func=lambda x: x - 1)
regr = TransformedTargetRegressor(regressor=LinearRegression(),
transformer=transformer)
y_pred = regr.fit(X, y).predict(X)
assert y.shape == y_pred.shape
# consistency forward transform
y_tran = regr.transformer_.transform(y)
_check_shifted_by_one(y, y_tran)
assert y.shape == y_pred.shape
# consistency inverse transform
assert_allclose(y, regr.transformer_.inverse_transform(
y_tran).squeeze())
# consistency of the regressor
lr = LinearRegression()
transformer2 = clone(transformer)
lr.fit(X, transformer2.fit_transform(y))
y_lr_pred = lr.predict(X)
assert_allclose(y_pred, transformer2.inverse_transform(y_lr_pred))
assert_allclose(regr.regressor_.coef_, lr.coef_)
def test_binary_classifier_class_weight():
"""tests binary classifier with classweights for each class"""
alpha = .1
n_samples = 50
n_iter = 20
tol = .00001
fit_intercept = True
X, y = make_blobs(n_samples=n_samples,
centers=2,
random_state=10,
cluster_std=0.1)
step_size = get_step_size(X, alpha, fit_intercept, classification=True)
classes = np.unique(y)
y_tmp = np.ones(n_samples)
y_tmp[y != classes[1]] = -1
y = y_tmp
class_weight = {1: .45, -1: .55}
clf1 = LogisticRegression(solver='sag',
C=1. / alpha / n_samples,
max_iter=n_iter,
tol=tol,
random_state=77,
fit_intercept=fit_intercept,
multi_class='ovr',
class_weight=class_weight)
clf2 = clone(clf1)
clf1.fit(X, y)
clf2.fit(sp.csr_matrix(X), y)
le = LabelEncoder()
class_weight_ = compute_class_weight(class_weight, np.unique(y), y)
sample_weight = class_weight_[le.fit_transform(y)]
spweights, spintercept = sag_sparse(X,
y,
step_size,
alpha,
n_iter=n_iter,
dloss=log_dloss,
sample_weight=sample_weight,
fit_intercept=fit_intercept)
spweights2, spintercept2 = sag_sparse(X,
y,
step_size,
alpha,
n_iter=n_iter,
dloss=log_dloss,
sparse=True,
sample_weight=sample_weight,
fit_intercept=fit_intercept)
assert_array_almost_equal(clf1.coef_.ravel(), spweights.ravel(), decimal=2)
assert_almost_equal(clf1.intercept_, spintercept, decimal=1)
assert_array_almost_equal(clf2.coef_.ravel(),
spweights2.ravel(),
decimal=2)
assert_almost_equal(clf2.intercept_, spintercept2, decimal=1)
def _check_behavior_2d(clf):
# 1d case
X = np.array([[0], [0], [0], [0]]) # ignored
y = np.array([1, 2, 1, 1])
est = clone(clf)
est.fit(X, y)
y_pred = est.predict(X)
assert y.shape == y_pred.shape
# 2d case
y = np.array([[1, 0],
[2, 0],
[1, 0],
[1, 3]])
est = clone(clf)
est.fit(X, y)
y_pred = est.predict(X)
assert y.shape == y_pred.shape
def test_clone_sparse_matrices():
sparse_matrix_classes = [
getattr(sp, name) for name in dir(sp) if name.endswith('_matrix')
]
for cls in sparse_matrix_classes:
sparse_matrix = cls(np.eye(5))
clf = MyEstimator(empty=sparse_matrix)
clf_cloned = clone(clf)
assert clf.empty.__class__ is clf_cloned.empty.__class__
assert_array_equal(clf.empty.toarray(), clf_cloned.empty.toarray())
def _check_behavior_2d_for_constant(clf):
# 2d case only
X = np.array([[0], [0], [0], [0]]) # ignored
y = np.array([[1, 0, 5, 4, 3],
[2, 0, 1, 2, 5],
[1, 0, 4, 5, 2],
[1, 3, 3, 2, 0]])
est = clone(clf)
est.fit(X, y)
y_pred = est.predict(X)
assert y.shape == y_pred.shape
def test_base_chain_random_order():
# Fit base chain with random order
X, Y = generate_multilabel_dataset_with_correlations()
for chain in [
ClassifierChain(LogisticRegression()),
RegressorChain(Ridge())
]:
chain_random = clone(chain).set_params(order='random', random_state=42)
chain_random.fit(X, Y)
chain_fixed = clone(chain).set_params(order=chain_random.order_)
chain_fixed.fit(X, Y)
assert_array_equal(chain_fixed.order_, chain_random.order_)
assert list(chain_random.order) != list(range(4))
assert len(chain_random.order_) == 4
assert len(set(chain_random.order_)) == 4
# Randomly ordered chain should behave identically to a fixed order
# chain with the same order.
for est1, est2 in zip(chain_random.estimators_,
chain_fixed.estimators_):
assert_array_almost_equal(est1.coef_, est2.coef_)
def test_warm_start_equal_n_estimators(GradientBoosting, X, y):
# Test if warm start with equal n_estimators does nothing
gb_1 = GradientBoosting(max_depth=2)
gb_1.fit(X, y)
gb_2 = clone(gb_1)
gb_2.set_params(max_iter=gb_1.max_iter, warm_start=True)
gb_2.fit(X, y)
# Check that both predictors are equal
_assert_predictor_equal(gb_1, gb_2, X)
def test_sag_regressor():
"""tests if the sag regressor performs well"""
xmin, xmax = -5, 5
n_samples = 20
tol = .001
max_iter = 50
alpha = 0.1
rng = np.random.RandomState(0)
X = np.linspace(xmin, xmax, n_samples).reshape(n_samples, 1)
# simple linear function without noise
y = 0.5 * X.ravel()
clf1 = Ridge(tol=tol,
solver='sag',
max_iter=max_iter,
alpha=alpha * n_samples,
random_state=rng)
clf2 = clone(clf1)
clf1.fit(X, y)
clf2.fit(sp.csr_matrix(X), y)
score1 = clf1.score(X, y)
score2 = clf2.score(X, y)
assert score1 > 0.99
assert score2 > 0.99
# simple linear function with noise
y = 0.5 * X.ravel() + rng.randn(n_samples, 1).ravel()
clf1 = Ridge(tol=tol,
solver='sag',
max_iter=max_iter,
alpha=alpha * n_samples)
clf2 = clone(clf1)
clf1.fit(X, y)
clf2.fit(sp.csr_matrix(X), y)
score1 = clf1.score(X, y)
score2 = clf2.score(X, y)
score2 = clf2.score(X, y)
assert score1 > 0.5
assert score2 > 0.5
def test_weighted_vs_repeated():
# a sample weight of N should yield the same result as an N-fold
# repetition of the sample
rng = np.random.RandomState(0)
sample_weight = rng.randint(1, 5, size=n_samples)
X_repeat = np.repeat(X, sample_weight, axis=0)
estimators = [
KMeans(init="k-means++", n_clusters=n_clusters, random_state=42),
KMeans(init="random", n_clusters=n_clusters, random_state=42),
KMeans(init=centers.copy(), n_clusters=n_clusters, random_state=42),
MiniBatchKMeans(n_clusters=n_clusters, batch_size=10, random_state=42)
]
for estimator in estimators:
est_weighted = clone(estimator).fit(X, sample_weight=sample_weight)
est_repeated = clone(estimator).fit(X_repeat)
repeated_labels = np.repeat(est_weighted.labels_, sample_weight)
assert_almost_equal(
v_measure_score(est_repeated.labels_, repeated_labels), 1.0)
if not isinstance(estimator, MiniBatchKMeans):
assert_almost_equal(_sort_centers(est_weighted.cluster_centers_),
_sort_centers(est_repeated.cluster_centers_))
def test_clone_2():
# Tests that clone doesn't copy everything.
# We first create an estimator, give it an own attribute, and
# make a copy of its original state. Then we check that the copy doesn't
# have the specific attribute we manually added to the initial estimator.
from mrex.feature_selection import SelectFpr, f_classif
selector = SelectFpr(f_classif, alpha=0.1)
selector.own_attribute = "test"
new_selector = clone(selector)
assert not hasattr(new_selector, "own_attribute")
def test_sag_classifier_computed_correctly():
"""tests if the binary classifier is computed correctly"""
alpha = .1
n_samples = 50
n_iter = 50
tol = .00001
fit_intercept = True
X, y = make_blobs(n_samples=n_samples,
centers=2,
random_state=0,
cluster_std=0.1)
step_size = get_step_size(X, alpha, fit_intercept, classification=True)
classes = np.unique(y)
y_tmp = np.ones(n_samples)
y_tmp[y != classes[1]] = -1
y = y_tmp
clf1 = LogisticRegression(solver='sag',
C=1. / alpha / n_samples,
max_iter=n_iter,
tol=tol,
random_state=77,
fit_intercept=fit_intercept,
multi_class='ovr')
clf2 = clone(clf1)
clf1.fit(X, y)
clf2.fit(sp.csr_matrix(X), y)
spweights, spintercept = sag_sparse(X,
y,
step_size,
alpha,
n_iter=n_iter,
dloss=log_dloss,
fit_intercept=fit_intercept)
spweights2, spintercept2 = sag_sparse(X,
y,
step_size,
alpha,
n_iter=n_iter,
dloss=log_dloss,
sparse=True,
fit_intercept=fit_intercept)
assert_array_almost_equal(clf1.coef_.ravel(), spweights.ravel(), decimal=2)
assert_almost_equal(clf1.intercept_, spintercept, decimal=1)
assert_array_almost_equal(clf2.coef_.ravel(),
spweights2.ravel(),
decimal=2)
assert_almost_equal(clf2.intercept_, spintercept2, decimal=1)
def test_kernel_clone(kernel):
# Test that mrex's clone works correctly on kernels.
kernel_cloned = clone(kernel)
# XXX: Should this be fixed?
# This differs from the mrex's estimators equality check.
assert kernel == kernel_cloned
assert id(kernel) != id(kernel_cloned)
# Check that all constructor parameters are equal.
assert kernel.get_params() == kernel_cloned.get_params()
# Check that all hyperparameters are equal.
check_hyperparameters_equal(kernel, kernel_cloned)
def test_multiclass_multioutput_estimator():
# test to check meta of meta estimators
svc = LinearSVC(random_state=0)
multi_class_svc = OneVsRestClassifier(svc)
multi_target_svc = MultiOutputClassifier(multi_class_svc)
multi_target_svc.fit(X, y)
predictions = multi_target_svc.predict(X)
assert (n_samples, n_outputs) == predictions.shape
# train the forest with each column and assert that predictions are equal
for i in range(3):
multi_class_svc_ = clone(multi_class_svc) # create a clone
multi_class_svc_.fit(X, y[:, i])
assert (list(multi_class_svc_.predict(X)) == list(predictions[:, i]))
def test_sag_regressor_computed_correctly():
"""tests if the sag regressor is computed correctly"""
alpha = .1
n_features = 10
n_samples = 40
max_iter = 50
tol = .000001
fit_intercept = True
rng = np.random.RandomState(0)
X = rng.normal(size=(n_samples, n_features))
w = rng.normal(size=n_features)
y = np.dot(X, w) + 2.
step_size = get_step_size(X, alpha, fit_intercept, classification=False)
clf1 = Ridge(fit_intercept=fit_intercept,
tol=tol,
solver='sag',
alpha=alpha * n_samples,
max_iter=max_iter)
clf2 = clone(clf1)
clf1.fit(X, y)
clf2.fit(sp.csr_matrix(X), y)
spweights1, spintercept1 = sag_sparse(X,
y,
step_size,
alpha,
n_iter=max_iter,
dloss=squared_dloss,
fit_intercept=fit_intercept)
spweights2, spintercept2 = sag_sparse(X,
y,
step_size,
alpha,
n_iter=max_iter,
dloss=squared_dloss,
sparse=True,
fit_intercept=fit_intercept)
assert_array_almost_equal(clf1.coef_.ravel(),
spweights1.ravel(),
decimal=3)
assert_almost_equal(clf1.intercept_, spintercept1, decimal=1)
def test_sparse_svc_clone_with_callable_kernel():
# Test that the "dense_fit" is called even though we use sparse input
# meaning that everything works fine.
a = svm.SVC(C=1,
kernel=lambda x, y: x * y.T,
probability=True,
random_state=0)
b = base.clone(a)
b.fit(X_sp, Y)
pred = b.predict(X_sp)
b.predict_proba(X_sp)
dense_svm = svm.SVC(C=1,
kernel=lambda x, y: np.dot(x, y.T),
probability=True,
random_state=0)
pred_dense = dense_svm.fit(X, Y).predict(X)
assert_array_equal(pred_dense, pred)
def test_nmf_sparse_input():
# Test that sparse matrices are accepted as input
from scipy.sparse import csc_matrix
rng = np.random.mtrand.RandomState(42)
A = np.abs(rng.randn(10, 10))
A[:, 2 * np.arange(5)] = 0
A_sparse = csc_matrix(A)
for solver in ('cd', 'mu'):
est1 = NMF(solver=solver, n_components=5, init='random',
random_state=0, tol=1e-2)
est2 = clone(est1)
W1 = est1.fit_transform(A)
W2 = est2.fit_transform(A_sparse)
H1 = est1.components_
H2 = est2.components_
assert_array_almost_equal(W1, W2)
assert_array_almost_equal(H1, H2)
def test_base_chain_crossval_fit_and_predict():
# Fit chain with cross_val_predict and verify predict
# performance
X, Y = generate_multilabel_dataset_with_correlations()
for chain in [
ClassifierChain(LogisticRegression()),
RegressorChain(Ridge())
]:
chain.fit(X, Y)
chain_cv = clone(chain).set_params(cv=3)
chain_cv.fit(X, Y)
Y_pred_cv = chain_cv.predict(X)
Y_pred = chain.predict(X)
assert Y_pred_cv.shape == Y_pred.shape
assert not np.all(Y_pred == Y_pred_cv)
if isinstance(chain, ClassifierChain):
assert jaccard_score(Y, Y_pred_cv, average='samples') > .4
else:
assert mean_squared_error(Y, Y_pred_cv) < .25
def test_sag_pobj_matches_ridge_regression():
"""tests if the sag pobj matches ridge reg"""
n_samples = 100
n_features = 10
alpha = 1.0
n_iter = 100
fit_intercept = False
rng = np.random.RandomState(10)
X = rng.normal(size=(n_samples, n_features))
true_w = rng.normal(size=n_features)
y = X.dot(true_w)
clf1 = Ridge(fit_intercept=fit_intercept,
tol=.00000000001,
solver='sag',
alpha=alpha,
max_iter=n_iter,
random_state=42)
clf2 = clone(clf1)
clf3 = Ridge(fit_intercept=fit_intercept,
tol=.00001,
solver='lsqr',
alpha=alpha,
max_iter=n_iter,
random_state=42)
clf1.fit(X, y)
clf2.fit(sp.csr_matrix(X), y)
clf3.fit(X, y)
pobj1 = get_pobj(clf1.coef_, alpha, X, y, squared_loss)
pobj2 = get_pobj(clf2.coef_, alpha, X, y, squared_loss)
pobj3 = get_pobj(clf3.coef_, alpha, X, y, squared_loss)
assert_array_almost_equal(pobj1, pobj2, decimal=4)
assert_array_almost_equal(pobj1, pobj3, decimal=4)
assert_array_almost_equal(pobj3, pobj2, decimal=4)
