226 lines
8.7 KiB
Python
226 lines
8.7 KiB
Python
import numpy as np
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from sklearn.metrics.cluster import adjusted_rand_score
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from sklearn.metrics.cluster import homogeneity_score
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from sklearn.metrics.cluster import completeness_score
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from sklearn.metrics.cluster import v_measure_score
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from sklearn.metrics.cluster import homogeneity_completeness_v_measure
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from sklearn.metrics.cluster import adjusted_mutual_info_score
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from sklearn.metrics.cluster import normalized_mutual_info_score
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from sklearn.metrics.cluster import mutual_info_score
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from sklearn.metrics.cluster import expected_mutual_information
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from sklearn.metrics.cluster import contingency_matrix
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from sklearn.metrics.cluster import entropy
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from sklearn.utils.testing import assert_raise_message
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from nose.tools import assert_almost_equal
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from nose.tools import assert_equal
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from numpy.testing import assert_array_almost_equal
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score_funcs = [
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adjusted_rand_score,
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homogeneity_score,
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completeness_score,
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v_measure_score,
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adjusted_mutual_info_score,
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normalized_mutual_info_score,
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]
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def test_error_messages_on_wrong_input():
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for score_func in score_funcs:
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expected = ('labels_true and labels_pred must have same size,'
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' got 2 and 3')
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assert_raise_message(ValueError, expected, score_func,
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[0, 1], [1, 1, 1])
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expected = "labels_true must be 1D: shape is (2"
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assert_raise_message(ValueError, expected, score_func,
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[[0, 1], [1, 0]], [1, 1, 1])
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expected = "labels_pred must be 1D: shape is (2"
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assert_raise_message(ValueError, expected, score_func,
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[0, 1, 0], [[1, 1], [0, 0]])
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def test_perfect_matches():
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for score_func in score_funcs:
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assert_equal(score_func([], []), 1.0)
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assert_equal(score_func([0], [1]), 1.0)
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assert_equal(score_func([0, 0, 0], [0, 0, 0]), 1.0)
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assert_equal(score_func([0, 1, 0], [42, 7, 42]), 1.0)
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assert_equal(score_func([0., 1., 0.], [42., 7., 42.]), 1.0)
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assert_equal(score_func([0., 1., 2.], [42., 7., 2.]), 1.0)
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assert_equal(score_func([0, 1, 2], [42, 7, 2]), 1.0)
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def test_homogeneous_but_not_complete_labeling():
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# homogeneous but not complete clustering
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h, c, v = homogeneity_completeness_v_measure(
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[0, 0, 0, 1, 1, 1],
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[0, 0, 0, 1, 2, 2])
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assert_almost_equal(h, 1.00, 2)
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assert_almost_equal(c, 0.69, 2)
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assert_almost_equal(v, 0.81, 2)
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def test_complete_but_not_homogeneous_labeling():
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# complete but not homogeneous clustering
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h, c, v = homogeneity_completeness_v_measure(
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[0, 0, 1, 1, 2, 2],
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[0, 0, 1, 1, 1, 1])
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assert_almost_equal(h, 0.58, 2)
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assert_almost_equal(c, 1.00, 2)
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assert_almost_equal(v, 0.73, 2)
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def test_not_complete_and_not_homogeneous_labeling():
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# neither complete nor homogeneous but not so bad either
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h, c, v = homogeneity_completeness_v_measure(
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[0, 0, 0, 1, 1, 1],
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[0, 1, 0, 1, 2, 2])
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assert_almost_equal(h, 0.67, 2)
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assert_almost_equal(c, 0.42, 2)
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assert_almost_equal(v, 0.52, 2)
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def test_non_consicutive_labels():
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# regression tests for labels with gaps
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h, c, v = homogeneity_completeness_v_measure(
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[0, 0, 0, 2, 2, 2],
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[0, 1, 0, 1, 2, 2])
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assert_almost_equal(h, 0.67, 2)
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assert_almost_equal(c, 0.42, 2)
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assert_almost_equal(v, 0.52, 2)
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h, c, v = homogeneity_completeness_v_measure(
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[0, 0, 0, 1, 1, 1],
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[0, 4, 0, 4, 2, 2])
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assert_almost_equal(h, 0.67, 2)
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assert_almost_equal(c, 0.42, 2)
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assert_almost_equal(v, 0.52, 2)
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ari_1 = adjusted_rand_score([0, 0, 0, 1, 1, 1], [0, 1, 0, 1, 2, 2])
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ari_2 = adjusted_rand_score([0, 0, 0, 1, 1, 1], [0, 4, 0, 4, 2, 2])
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assert_almost_equal(ari_1, 0.24, 2)
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assert_almost_equal(ari_2, 0.24, 2)
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def uniform_labelings_scores(score_func, n_samples, k_range, n_runs=10,
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seed=42):
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# Compute score for random uniform cluster labelings
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random_labels = np.random.RandomState(seed).random_integers
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scores = np.zeros((len(k_range), n_runs))
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for i, k in enumerate(k_range):
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for j in range(n_runs):
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labels_a = random_labels(low=0, high=k - 1, size=n_samples)
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labels_b = random_labels(low=0, high=k - 1, size=n_samples)
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scores[i, j] = score_func(labels_a, labels_b)
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return scores
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def test_adjustment_for_chance():
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# Check that adjusted scores are almost zero on random labels
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n_clusters_range = [2, 10, 50, 90]
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n_samples = 100
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n_runs = 10
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scores = uniform_labelings_scores(
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adjusted_rand_score, n_samples, n_clusters_range, n_runs)
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max_abs_scores = np.abs(scores).max(axis=1)
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assert_array_almost_equal(max_abs_scores, [0.02, 0.03, 0.03, 0.02], 2)
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def test_adjusted_mutual_info_score():
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# Compute the Adjusted Mutual Information and test against known values
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labels_a = np.array([1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3])
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labels_b = np.array([1, 1, 1, 1, 2, 1, 2, 2, 2, 2, 3, 1, 3, 3, 3, 2, 2])
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# Mutual information
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mi = mutual_info_score(labels_a, labels_b)
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assert_almost_equal(mi, 0.41022, 5)
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# Expected mutual information
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C = contingency_matrix(labels_a, labels_b)
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n_samples = np.sum(C)
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emi = expected_mutual_information(C, n_samples)
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assert_almost_equal(emi, 0.15042, 5)
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# Adjusted mutual information
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ami = adjusted_mutual_info_score(labels_a, labels_b)
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assert_almost_equal(ami, 0.27502, 5)
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ami = adjusted_mutual_info_score([1, 1, 2, 2], [2, 2, 3, 3])
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assert_equal(ami, 1.0)
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# Test with a very large array
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a110 = np.array([list(labels_a) * 110]).flatten()
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b110 = np.array([list(labels_b) * 110]).flatten()
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ami = adjusted_mutual_info_score(a110, b110)
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# This is not accurate to more than 2 places
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assert_almost_equal(ami, 0.37, 2)
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def test_entropy():
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ent = entropy([0, 0, 42.])
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assert_almost_equal(ent, 0.6365141, 5)
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assert_almost_equal(entropy([]), 1)
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def test_contingency_matrix():
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labels_a = np.array([1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3])
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labels_b = np.array([1, 1, 1, 1, 2, 1, 2, 2, 2, 2, 3, 1, 3, 3, 3, 2, 2])
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C = contingency_matrix(labels_a, labels_b)
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C2 = np.histogram2d(labels_a, labels_b,
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bins=(np.arange(1, 5),
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np.arange(1, 5)))[0]
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assert_array_almost_equal(C, C2)
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C = contingency_matrix(labels_a, labels_b, eps=.1)
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assert_array_almost_equal(C, C2 + .1)
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def test_exactly_zero_info_score():
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# Check numerical stability when information is exactly zero
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for i in np.logspace(1, 4, 4).astype(np.int):
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labels_a, labels_b = np.ones(i, dtype=np.int),\
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np.arange(i, dtype=np.int)
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assert_equal(normalized_mutual_info_score(labels_a, labels_b,
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max_n_classes=1e4), 0.0)
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assert_equal(v_measure_score(labels_a, labels_b,
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max_n_classes=1e4), 0.0)
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assert_equal(adjusted_mutual_info_score(labels_a, labels_b,
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max_n_classes=1e4), 0.0)
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assert_equal(normalized_mutual_info_score(labels_a, labels_b,
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max_n_classes=1e4), 0.0)
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def test_v_measure_and_mutual_information(seed=36):
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# Check relation between v_measure, entropy and mutual information
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for i in np.logspace(1, 4, 4).astype(np.int):
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random_state = np.random.RandomState(seed)
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labels_a, labels_b = random_state.random_integers(0, 10, i),\
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random_state.random_integers(0, 10, i)
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assert_almost_equal(v_measure_score(labels_a, labels_b),
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2.0 * mutual_info_score(labels_a, labels_b) /
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(entropy(labels_a) + entropy(labels_b)), 0)
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def test_max_n_classes():
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rng = np.random.RandomState(seed=0)
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labels_true = rng.rand(53)
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labels_pred = rng.rand(53)
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labels_zero = np.zeros(53)
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labels_true[:2] = 0
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labels_zero[:3] = 1
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labels_pred[:2] = 0
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for score_func in score_funcs:
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expected = ("Too many classes for a clustering metric. If you "
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"want to increase the limit, pass parameter "
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"max_n_classes to the scoring function")
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assert_raise_message(ValueError, expected, score_func,
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labels_true, labels_pred,
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max_n_classes=50)
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expected = ("Too many clusters for a clustering metric. If you "
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"want to increase the limit, pass parameter "
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"max_n_classes to the scoring function")
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assert_raise_message(ValueError, expected, score_func,
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labels_zero, labels_pred,
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max_n_classes=50)
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