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import numpy as np
from nose.tools import assert_almost_equal
from nose.tools import assert_equal
from numpy.testing import assert_array_almost_equal
from sklearn.metrics.cluster import adjusted_mutual_info_score
from sklearn.metrics.cluster import adjusted_rand_score
from sklearn.metrics.cluster import completeness_score
from sklearn.metrics.cluster import contingency_matrix
from sklearn.metrics.cluster import entropy
from sklearn.metrics.cluster import expected_mutual_information
from sklearn.metrics.cluster import fowlkes_mallows_score
from sklearn.metrics.cluster import homogeneity_completeness_v_measure
from sklearn.metrics.cluster import homogeneity_score
from sklearn.metrics.cluster import mutual_info_score
from sklearn.metrics.cluster import normalized_mutual_info_score
from sklearn.metrics.cluster import v_measure_score
from sklearn.utils.testing import assert_raise_message
score_funcs = [
adjusted_rand_score,
homogeneity_score,
completeness_score,
v_measure_score,
adjusted_mutual_info_score,
normalized_mutual_info_score,
]
def test_error_messages_on_wrong_input():
for score_func in score_funcs:
expected = ('labels_true and labels_pred must have same size,'
' got 2 and 3')
assert_raise_message(ValueError, expected, score_func,
[0, 1], [1, 1, 1])
expected = "labels_true must be 1D: shape is (2"
assert_raise_message(ValueError, expected, score_func,
[[0, 1], [1, 0]], [1, 1, 1])
expected = "labels_pred must be 1D: shape is (2"
assert_raise_message(ValueError, expected, score_func,
[0, 1, 0], [[1, 1], [0, 0]])
def test_perfect_matches():
for score_func in score_funcs:
assert_equal(score_func([], []), 1.0)
assert_equal(score_func([0], [1]), 1.0)
assert_equal(score_func([0, 0, 0], [0, 0, 0]), 1.0)
assert_equal(score_func([0, 1, 0], [42, 7, 42]), 1.0)
assert_equal(score_func([0., 1., 0.], [42., 7., 42.]), 1.0)
assert_equal(score_func([0., 1., 2.], [42., 7., 2.]), 1.0)
assert_equal(score_func([0, 1, 2], [42, 7, 2]), 1.0)
def test_homogeneous_but_not_complete_labeling():
# homogeneous but not complete clustering
h, c, v = homogeneity_completeness_v_measure(
[0, 0, 0, 1, 1, 1],
[0, 0, 0, 1, 2, 2])
assert_almost_equal(h, 1.00, 2)
assert_almost_equal(c, 0.69, 2)
assert_almost_equal(v, 0.81, 2)
def test_complete_but_not_homogeneous_labeling():
# complete but not homogeneous clustering
h, c, v = homogeneity_completeness_v_measure(
[0, 0, 1, 1, 2, 2],
[0, 0, 1, 1, 1, 1])
assert_almost_equal(h, 0.58, 2)
assert_almost_equal(c, 1.00, 2)
assert_almost_equal(v, 0.73, 2)
def test_not_complete_and_not_homogeneous_labeling():
# neither complete nor homogeneous but not so bad either
h, c, v = homogeneity_completeness_v_measure(
[0, 0, 0, 1, 1, 1],
[0, 1, 0, 1, 2, 2])
assert_almost_equal(h, 0.67, 2)
assert_almost_equal(c, 0.42, 2)
assert_almost_equal(v, 0.52, 2)
def test_non_consicutive_labels():
# regression tests for labels with gaps
h, c, v = homogeneity_completeness_v_measure(
[0, 0, 0, 2, 2, 2],
[0, 1, 0, 1, 2, 2])
assert_almost_equal(h, 0.67, 2)
assert_almost_equal(c, 0.42, 2)
assert_almost_equal(v, 0.52, 2)
h, c, v = homogeneity_completeness_v_measure(
[0, 0, 0, 1, 1, 1],
[0, 4, 0, 4, 2, 2])
assert_almost_equal(h, 0.67, 2)
assert_almost_equal(c, 0.42, 2)
assert_almost_equal(v, 0.52, 2)
ari_1 = adjusted_rand_score([0, 0, 0, 1, 1, 1], [0, 1, 0, 1, 2, 2])
ari_2 = adjusted_rand_score([0, 0, 0, 1, 1, 1], [0, 4, 0, 4, 2, 2])
assert_almost_equal(ari_1, 0.24, 2)
assert_almost_equal(ari_2, 0.24, 2)
def uniform_labelings_scores(score_func, n_samples, k_range, n_runs=10,
seed=42):
# Compute score for random uniform cluster labelings
random_labels = np.random.RandomState(seed).randint
scores = np.zeros((len(k_range), n_runs))
for i, k in enumerate(k_range):
for j in range(n_runs):
labels_a = random_labels(low=0, high=k, size=n_samples)
labels_b = random_labels(low=0, high=k, size=n_samples)
scores[i, j] = score_func(labels_a, labels_b)
return scores
def test_adjustment_for_chance():
# Check that adjusted scores are almost zero on random labels
n_clusters_range = [2, 10, 50, 90]
n_samples = 100
n_runs = 10
scores = uniform_labelings_scores(
adjusted_rand_score, n_samples, n_clusters_range, n_runs)
max_abs_scores = np.abs(scores).max(axis=1)
assert_array_almost_equal(max_abs_scores, [0.02, 0.03, 0.03, 0.02], 2)
def test_adjusted_mutual_info_score():
# Compute the Adjusted Mutual Information and test against known values
labels_a = np.array([1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3])
labels_b = np.array([1, 1, 1, 1, 2, 1, 2, 2, 2, 2, 3, 1, 3, 3, 3, 2, 2])
# Mutual information
mi = mutual_info_score(labels_a, labels_b)
assert_almost_equal(mi, 0.41022, 5)
# with provided sparse contingency
C = contingency_matrix(labels_a, labels_b, sparse=True)
mi = mutual_info_score(labels_a, labels_b, contingency=C)
assert_almost_equal(mi, 0.41022, 5)
# with provided dense contingency
C = contingency_matrix(labels_a, labels_b)
mi = mutual_info_score(labels_a, labels_b, contingency=C)
assert_almost_equal(mi, 0.41022, 5)
# Expected mutual information
n_samples = C.sum()
emi = expected_mutual_information(C, n_samples)
assert_almost_equal(emi, 0.15042, 5)
# Adjusted mutual information
ami = adjusted_mutual_info_score(labels_a, labels_b)
assert_almost_equal(ami, 0.27502, 5)
ami = adjusted_mutual_info_score([1, 1, 2, 2], [2, 2, 3, 3])
assert_equal(ami, 1.0)
# Test with a very large array
a110 = np.array([list(labels_a) * 110]).flatten()
b110 = np.array([list(labels_b) * 110]).flatten()
ami = adjusted_mutual_info_score(a110, b110)
# This is not accurate to more than 2 places
assert_almost_equal(ami, 0.37, 2)
def test_expected_mutual_info_overflow():
# Test for regression where contingency cell exceeds 2**16
# leading to overflow in np.outer, resulting in EMI > 1
assert expected_mutual_information(np.array([[70000]]), 70000) <= 1
def test_entropy():
ent = entropy([0, 0, 42.])
assert_almost_equal(ent, 0.6365141, 5)
assert_almost_equal(entropy([]), 1)
def test_contingency_matrix():
labels_a = np.array([1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3])
labels_b = np.array([1, 1, 1, 1, 2, 1, 2, 2, 2, 2, 3, 1, 3, 3, 3, 2, 2])
C = contingency_matrix(labels_a, labels_b)
C2 = np.histogram2d(labels_a, labels_b,
bins=(np.arange(1, 5),
np.arange(1, 5)))[0]
assert_array_almost_equal(C, C2)
C = contingency_matrix(labels_a, labels_b, eps=.1)
assert_array_almost_equal(C, C2 + .1)
def test_contingency_matrix_sparse():
labels_a = np.array([1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3])
labels_b = np.array([1, 1, 1, 1, 2, 1, 2, 2, 2, 2, 3, 1, 3, 3, 3, 2, 2])
C = contingency_matrix(labels_a, labels_b)
C_sparse = contingency_matrix(labels_a, labels_b, sparse=True).toarray()
assert_array_almost_equal(C, C_sparse)
C_sparse = assert_raise_message(ValueError,
"Cannot set 'eps' when sparse=True",
contingency_matrix, labels_a, labels_b,
eps=1e-10, sparse=True)
def test_exactly_zero_info_score():
# Check numerical stability when information is exactly zero
for i in np.logspace(1, 4, 4).astype(np.int):
labels_a, labels_b = (np.ones(i, dtype=np.int),
np.arange(i, dtype=np.int))
assert_equal(normalized_mutual_info_score(labels_a, labels_b), 0.0)
assert_equal(v_measure_score(labels_a, labels_b), 0.0)
assert_equal(adjusted_mutual_info_score(labels_a, labels_b), 0.0)
assert_equal(normalized_mutual_info_score(labels_a, labels_b), 0.0)
def test_v_measure_and_mutual_information(seed=36):
# Check relation between v_measure, entropy and mutual information
for i in np.logspace(1, 4, 4).astype(np.int):
random_state = np.random.RandomState(seed)
labels_a, labels_b = (random_state.randint(0, 10, i),
random_state.randint(0, 10, i))
assert_almost_equal(v_measure_score(labels_a, labels_b),
2.0 * mutual_info_score(labels_a, labels_b) /
(entropy(labels_a) + entropy(labels_b)), 0)
def test_fowlkes_mallows_score():
# General case
score = fowlkes_mallows_score([0, 0, 0, 1, 1, 1],
[0, 0, 1, 1, 2, 2])
assert_almost_equal(score, 4. / np.sqrt(12. * 6.))
# Perfect match but where the label names changed
perfect_score = fowlkes_mallows_score([0, 0, 0, 1, 1, 1],
[1, 1, 1, 0, 0, 0])
assert_almost_equal(perfect_score, 1.)
# Worst case
worst_score = fowlkes_mallows_score([0, 0, 0, 0, 0, 0],
[0, 1, 2, 3, 4, 5])
assert_almost_equal(worst_score, 0.)
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