1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
|
# Author: Alexandre Gramfort <alexandre.gramfort@inria.fr>
# Fabian Pedregosa <fabian.pedregosa@inria.fr>
#
# License: BSD 3 clause
import numpy as np
from sklearn.utils.testing import assert_array_equal
from sklearn.utils.testing import assert_array_almost_equal
from sklearn.utils.testing import assert_almost_equal
from sklearn.utils.testing import assert_array_less
from sklearn.utils.testing import assert_equal
from sklearn.utils.testing import SkipTest
from sklearn.utils import check_random_state
from sklearn.linear_model.bayes import BayesianRidge, ARDRegression
from sklearn.linear_model import Ridge
from sklearn import datasets
def test_bayesian_on_diabetes():
# Test BayesianRidge on diabetes
raise SkipTest("test_bayesian_on_diabetes is broken")
diabetes = datasets.load_diabetes()
X, y = diabetes.data, diabetes.target
clf = BayesianRidge(compute_score=True)
# Test with more samples than features
clf.fit(X, y)
# Test that scores are increasing at each iteration
assert_array_equal(np.diff(clf.scores_) > 0, True)
# Test with more features than samples
X = X[:5, :]
y = y[:5]
clf.fit(X, y)
# Test that scores are increasing at each iteration
assert_array_equal(np.diff(clf.scores_) > 0, True)
def test_bayesian_ridge_parameter():
# Test correctness of lambda_ and alpha_ parameters (GitHub issue #8224)
X = np.array([[1, 1], [3, 4], [5, 7], [4, 1], [2, 6], [3, 10], [3, 2]])
y = np.array([1, 2, 3, 2, 0, 4, 5]).T
# A Ridge regression model using an alpha value equal to the ratio of
# lambda_ and alpha_ from the Bayesian Ridge model must be identical
br_model = BayesianRidge(compute_score=True).fit(X, y)
rr_model = Ridge(alpha=br_model.lambda_ / br_model.alpha_).fit(X, y)
assert_array_almost_equal(rr_model.coef_, br_model.coef_)
assert_almost_equal(rr_model.intercept_, br_model.intercept_)
def test_bayesian_sample_weights():
# Test correctness of the sample_weights method
X = np.array([[1, 1], [3, 4], [5, 7], [4, 1], [2, 6], [3, 10], [3, 2]])
y = np.array([1, 2, 3, 2, 0, 4, 5]).T
w = np.array([4, 3, 3, 1, 1, 2, 3]).T
# A Ridge regression model using an alpha value equal to the ratio of
# lambda_ and alpha_ from the Bayesian Ridge model must be identical
br_model = BayesianRidge(compute_score=True).fit(X, y, sample_weight=w)
rr_model = Ridge(alpha=br_model.lambda_ / br_model.alpha_).fit(
X, y, sample_weight=w)
assert_array_almost_equal(rr_model.coef_, br_model.coef_)
assert_almost_equal(rr_model.intercept_, br_model.intercept_)
def test_toy_bayesian_ridge_object():
# Test BayesianRidge on toy
X = np.array([[1], [2], [6], [8], [10]])
Y = np.array([1, 2, 6, 8, 10])
clf = BayesianRidge(compute_score=True)
clf.fit(X, Y)
# Check that the model could approximately learn the identity function
test = [[1], [3], [4]]
assert_array_almost_equal(clf.predict(test), [1, 3, 4], 2)
def test_prediction_bayesian_ridge_ard_with_constant_input():
# Test BayesianRidge and ARDRegression predictions for edge case of
# constant target vectors
n_samples = 4
n_features = 5
random_state = check_random_state(42)
constant_value = random_state.rand()
X = random_state.random_sample((n_samples, n_features))
y = np.full(n_samples, constant_value,
dtype=np.array(constant_value).dtype)
expected = np.full(n_samples, constant_value,
dtype=np.array(constant_value).dtype)
for clf in [BayesianRidge(), ARDRegression()]:
y_pred = clf.fit(X, y).predict(X)
assert_array_almost_equal(y_pred, expected)
def test_std_bayesian_ridge_ard_with_constant_input():
# Test BayesianRidge and ARDRegression standard dev. for edge case of
# constant target vector
# The standard dev. should be relatively small (< 0.01 is tested here)
n_samples = 4
n_features = 5
random_state = check_random_state(42)
constant_value = random_state.rand()
X = random_state.random_sample((n_samples, n_features))
y = np.full(n_samples, constant_value,
dtype=np.array(constant_value).dtype)
expected_upper_boundary = 0.01
for clf in [BayesianRidge(), ARDRegression()]:
_, y_std = clf.fit(X, y).predict(X, return_std=True)
assert_array_less(y_std, expected_upper_boundary)
def test_update_of_sigma_in_ard():
# Checks that `sigma_` is updated correctly after the last iteration
# of the ARDRegression algorithm. See issue #10128.
X = np.array([[1, 0],
[0, 0]])
y = np.array([0, 0])
clf = ARDRegression(n_iter=1)
clf.fit(X, y)
# With the inputs above, ARDRegression prunes one of the two coefficients
# in the first iteration. Hence, the expected shape of `sigma_` is (1, 1).
assert_equal(clf.sigma_.shape, (1, 1))
# Ensure that no error is thrown at prediction stage
clf.predict(X, return_std=True)
def test_toy_ard_object():
# Test BayesianRegression ARD classifier
X = np.array([[1], [2], [3]])
Y = np.array([1, 2, 3])
clf = ARDRegression(compute_score=True)
clf.fit(X, Y)
# Check that the model could approximately learn the identity function
test = [[1], [3], [4]]
assert_array_almost_equal(clf.predict(test), [1, 3, 4], 2)
def test_return_std():
# Test return_std option for both Bayesian regressors
def f(X):
return np.dot(X, w) + b
def f_noise(X, noise_mult):
return f(X) + np.random.randn(X.shape[0]) * noise_mult
d = 5
n_train = 50
n_test = 10
w = np.array([1.0, 0.0, 1.0, -1.0, 0.0])
b = 1.0
X = np.random.random((n_train, d))
X_test = np.random.random((n_test, d))
for decimal, noise_mult in enumerate([1, 0.1, 0.01]):
y = f_noise(X, noise_mult)
m1 = BayesianRidge()
m1.fit(X, y)
y_mean1, y_std1 = m1.predict(X_test, return_std=True)
assert_array_almost_equal(y_std1, noise_mult, decimal=decimal)
m2 = ARDRegression()
m2.fit(X, y)
y_mean2, y_std2 = m2.predict(X_test, return_std=True)
assert_array_almost_equal(y_std2, noise_mult, decimal=decimal)
|
