71 lines
2.2 KiB
Python
71 lines
2.2 KiB
Python
"""
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Testing for mean shift clustering methods
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"""
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import numpy as np
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from sklearn.utils.testing import assert_equal
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from sklearn.utils.testing import assert_true
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from sklearn.cluster import MeanShift
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from sklearn.cluster import mean_shift
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from sklearn.cluster import estimate_bandwidth
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from sklearn.cluster import get_bin_seeds
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from sklearn.datasets.samples_generator import make_blobs
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n_clusters = 3
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centers = np.array([[1, 1], [-1, -1], [1, -1]]) + 10
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X, _ = make_blobs(n_samples=500, n_features=2, centers=centers,
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cluster_std=0.4, shuffle=True, random_state=0)
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def test_mean_shift():
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""" Test MeanShift algorithm
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"""
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bandwidth = 1.2
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bandwidth_ = estimate_bandwidth(X, n_samples=300)
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assert_true(0.9 <= bandwidth_ <= 1.5)
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ms = MeanShift(bandwidth=bandwidth)
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labels = ms.fit(X).labels_
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cluster_centers = ms.cluster_centers_
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labels_unique = np.unique(labels)
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n_clusters_ = len(labels_unique)
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assert_equal(n_clusters_, n_clusters)
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cluster_centers, labels = mean_shift(X, bandwidth=bandwidth)
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labels_unique = np.unique(labels)
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n_clusters_ = len(labels_unique)
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assert_equal(n_clusters_, n_clusters)
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def test_bin_seeds():
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"""
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Test the bin seeding technique which can be used in the mean shift
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algorithm
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"""
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# Data is just 6 points in the plane
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X = np.array([[1., 1.], [1.5, 1.5], [1.8, 1.2],
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[2., 1.], [2.1, 1.1], [0., 0.]])
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# With a bin coarseness of 1.0 and min_bin_freq of 1, 3 bins should be
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# found
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ground_truth = set([(1., 1.), (2., 1.), (0., 0.)])
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test_bins = get_bin_seeds(X, 1, 1)
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test_result = set([tuple(p) for p in test_bins])
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assert_true(len(ground_truth.symmetric_difference(test_result)) == 0)
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# With a bin coarseness of 1.0 and min_bin_freq of 2, 2 bins should be
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# found
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ground_truth = set([(1., 1.), (2., 1.)])
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test_bins = get_bin_seeds(X, 1, 2)
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test_result = set([tuple(p) for p in test_bins])
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assert_true(len(ground_truth.symmetric_difference(test_result)) == 0)
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# With a bin size of 0.01 and min_bin_freq of 1, 6 bins should be found
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test_bins = get_bin_seeds(X, 0.01, 1)
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test_result = set([tuple(p) for p in test_bins])
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assert_true(len(test_result) == 6)
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