Uploaded Test files

venv/Lib/site-packages/sklearn/cluster/tests/test_mean_shift.py

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+"""
+Testing for mean shift clustering methods
+
+"""
+
+import numpy as np
+import warnings
+import pytest
+
+from scipy import sparse
+
+from sklearn.utils._testing import assert_array_equal
+from sklearn.utils._testing import assert_array_almost_equal
+from sklearn.utils._testing import assert_raise_message
+from sklearn.utils._testing import assert_allclose
+
+from sklearn.cluster import MeanShift
+from sklearn.cluster import mean_shift
+from sklearn.cluster import estimate_bandwidth
+from sklearn.cluster import get_bin_seeds
+from sklearn.datasets import make_blobs
+from sklearn.metrics import v_measure_score
+
+
+n_clusters = 3
+centers = np.array([[1, 1], [-1, -1], [1, -1]]) + 10
+X, _ = make_blobs(n_samples=300, n_features=2, centers=centers,
+                  cluster_std=0.4, shuffle=True, random_state=11)
+
+
+def test_estimate_bandwidth():
+    # Test estimate_bandwidth
+    bandwidth = estimate_bandwidth(X, n_samples=200)
+    assert 0.9 <= bandwidth <= 1.5
+
+
+def test_estimate_bandwidth_1sample():
+    # Test estimate_bandwidth when n_samples=1 and quantile<1, so that
+    # n_neighbors is set to 1.
+    bandwidth = estimate_bandwidth(X, n_samples=1, quantile=0.3)
+    assert bandwidth == pytest.approx(0., abs=1e-5)
+
+
+@pytest.mark.parametrize("bandwidth, cluster_all, expected, "
+                         "first_cluster_label",
+                         [(1.2, True, 3, 0), (1.2, False, 4, -1)])
+def test_mean_shift(bandwidth, cluster_all, expected, first_cluster_label):
+    # Test MeanShift algorithm
+    ms = MeanShift(bandwidth=bandwidth, cluster_all=cluster_all)
+    labels = ms.fit(X).labels_
+    labels_unique = np.unique(labels)
+    n_clusters_ = len(labels_unique)
+    assert n_clusters_ == expected
+    assert labels_unique[0] == first_cluster_label
+
+    cluster_centers, labels_mean_shift = mean_shift(X, cluster_all=cluster_all)
+    labels_mean_shift_unique = np.unique(labels_mean_shift)
+    n_clusters_mean_shift = len(labels_mean_shift_unique)
+    assert n_clusters_mean_shift == expected
+    assert labels_mean_shift_unique[0] == first_cluster_label
+
+
+def test_mean_shift_negative_bandwidth():
+    bandwidth = -1
+    ms = MeanShift(bandwidth=bandwidth)
+    msg = (r"bandwidth needs to be greater than zero or None,"
+           r" got -1\.000000")
+    with pytest.raises(ValueError, match=msg):
+        ms.fit(X)
+
+
+def test_estimate_bandwidth_with_sparse_matrix():
+    # Test estimate_bandwidth with sparse matrix
+    X = sparse.lil_matrix((1000, 1000))
+    msg = "A sparse matrix was passed, but dense data is required."
+    assert_raise_message(TypeError, msg, estimate_bandwidth, X)
+
+
+def test_parallel():
+    centers = np.array([[1, 1], [-1, -1], [1, -1]]) + 10
+    X, _ = make_blobs(n_samples=50, n_features=2, centers=centers,
+                      cluster_std=0.4, shuffle=True, random_state=11)
+
+    ms1 = MeanShift(n_jobs=2)
+    ms1.fit(X)
+
+    ms2 = MeanShift()
+    ms2.fit(X)
+
+    assert_array_almost_equal(ms1.cluster_centers_, ms2.cluster_centers_)
+    assert_array_equal(ms1.labels_, ms2.labels_)
+
+
+def test_meanshift_predict():
+    # Test MeanShift.predict
+    ms = MeanShift(bandwidth=1.2)
+    labels = ms.fit_predict(X)
+    labels2 = ms.predict(X)
+    assert_array_equal(labels, labels2)
+
+
+def test_meanshift_all_orphans():
+    # init away from the data, crash with a sensible warning
+    ms = MeanShift(bandwidth=0.1, seeds=[[-9, -9], [-10, -10]])
+    msg = "No point was within bandwidth=0.1"
+    assert_raise_message(ValueError, msg, ms.fit, X,)
+
+
+def test_unfitted():
+    # Non-regression: before fit, there should be not fitted attributes.
+    ms = MeanShift()
+    assert not hasattr(ms, "cluster_centers_")
+    assert not hasattr(ms, "labels_")
+
+
+def test_cluster_intensity_tie():
+    X = np.array([[1, 1], [2, 1], [1, 0],
+                  [4, 7], [3, 5], [3, 6]])
+    c1 = MeanShift(bandwidth=2).fit(X)
+
+    X = np.array([[4, 7], [3, 5], [3, 6],
+                  [1, 1], [2, 1], [1, 0]])
+    c2 = MeanShift(bandwidth=2).fit(X)
+    assert_array_equal(c1.labels_, [1, 1, 1, 0, 0, 0])
+    assert_array_equal(c2.labels_, [0, 0, 0, 1, 1, 1])
+
+
+def test_bin_seeds():
+    # Test the bin seeding technique which can be used in the mean shift
+    # algorithm
+    # Data is just 6 points in the plane
+    X = np.array([[1., 1.], [1.4, 1.4], [1.8, 1.2],
+                  [2., 1.], [2.1, 1.1], [0., 0.]])
+
+    # With a bin coarseness of 1.0 and min_bin_freq of 1, 3 bins should be
+    # found
+    ground_truth = {(1., 1.), (2., 1.), (0., 0.)}
+    test_bins = get_bin_seeds(X, 1, 1)
+    test_result = set(tuple(p) for p in test_bins)
+    assert len(ground_truth.symmetric_difference(test_result)) == 0
+
+    # With a bin coarseness of 1.0 and min_bin_freq of 2, 2 bins should be
+    # found
+    ground_truth = {(1., 1.), (2., 1.)}
+    test_bins = get_bin_seeds(X, 1, 2)
+    test_result = set(tuple(p) for p in test_bins)
+    assert len(ground_truth.symmetric_difference(test_result)) == 0
+
+    # With a bin size of 0.01 and min_bin_freq of 1, 6 bins should be found
+    # we bail and use the whole data here.
+    with warnings.catch_warnings(record=True):
+        test_bins = get_bin_seeds(X, 0.01, 1)
+    assert_array_almost_equal(test_bins, X)
+
+    # tight clusters around [0, 0] and [1, 1], only get two bins
+    X, _ = make_blobs(n_samples=100, n_features=2, centers=[[0, 0], [1, 1]],
+                      cluster_std=0.1, random_state=0)
+    test_bins = get_bin_seeds(X, 1)
+    assert_array_equal(test_bins, [[0, 0], [1, 1]])
+
+
+@pytest.mark.parametrize('max_iter', [1, 100])
+def test_max_iter(max_iter):
+    clusters1, _ = mean_shift(X, max_iter=max_iter)
+    ms = MeanShift(max_iter=max_iter).fit(X)
+    clusters2 = ms.cluster_centers_
+
+    assert ms.n_iter_ <= ms.max_iter
+    assert len(clusters1) == len(clusters2)
+
+    for c1, c2 in zip(clusters1, clusters2):
+        assert np.allclose(c1, c2)
+
+
+def test_mean_shift_zero_bandwidth():
+    # Check that mean shift works when the estimated bandwidth is 0.
+    X = np.array([1, 1, 1, 2, 2, 2, 3, 3]).reshape(-1, 1)
+
+    # estimate_bandwidth with default args returns 0 on this dataset
+    bandwidth = estimate_bandwidth(X)
+    assert bandwidth == 0
+
+    # get_bin_seeds with a 0 bin_size should return the dataset itself
+    assert get_bin_seeds(X, bin_size=bandwidth) is X
+
+    # MeanShift with binning and a 0 estimated bandwidth should be equivalent
+    # to no binning.
+    ms_binning = MeanShift(bin_seeding=True, bandwidth=None).fit(X)
+    ms_nobinning = MeanShift(bin_seeding=False).fit(X)
+    expected_labels = np.array([0, 0, 0, 1, 1, 1, 2, 2])
+
+    assert v_measure_score(ms_binning.labels_, expected_labels) == 1
+    assert v_measure_score(ms_nobinning.labels_, expected_labels) == 1
+    assert_allclose(ms_binning.cluster_centers_, ms_nobinning.cluster_centers_)