372 lines
13 KiB
Python
372 lines
13 KiB
Python
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# Author: Vlad Niculae
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# License: BSD 3 clause
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import sys
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import numpy as np
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import pytest
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from numpy.testing import assert_array_equal
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from sklearn.decomposition import PCA, MiniBatchSparsePCA, SparsePCA
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from sklearn.utils import check_random_state
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from sklearn.utils._testing import (
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assert_allclose,
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assert_array_almost_equal,
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if_safe_multiprocessing_with_blas,
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)
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from sklearn.utils.extmath import svd_flip
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def generate_toy_data(n_components, n_samples, image_size, random_state=None):
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n_features = image_size[0] * image_size[1]
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rng = check_random_state(random_state)
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U = rng.randn(n_samples, n_components)
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V = rng.randn(n_components, n_features)
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centers = [(3, 3), (6, 7), (8, 1)]
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sz = [1, 2, 1]
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for k in range(n_components):
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img = np.zeros(image_size)
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xmin, xmax = centers[k][0] - sz[k], centers[k][0] + sz[k]
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ymin, ymax = centers[k][1] - sz[k], centers[k][1] + sz[k]
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img[xmin:xmax][:, ymin:ymax] = 1.0
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V[k, :] = img.ravel()
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# Y is defined by : Y = UV + noise
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Y = np.dot(U, V)
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Y += 0.1 * rng.randn(Y.shape[0], Y.shape[1]) # Add noise
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return Y, U, V
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# SparsePCA can be a bit slow. To avoid having test times go up, we
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# test different aspects of the code in the same test
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def test_correct_shapes():
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rng = np.random.RandomState(0)
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X = rng.randn(12, 10)
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spca = SparsePCA(n_components=8, random_state=rng)
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U = spca.fit_transform(X)
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assert spca.components_.shape == (8, 10)
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assert U.shape == (12, 8)
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# test overcomplete decomposition
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spca = SparsePCA(n_components=13, random_state=rng)
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U = spca.fit_transform(X)
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assert spca.components_.shape == (13, 10)
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assert U.shape == (12, 13)
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def test_fit_transform():
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alpha = 1
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rng = np.random.RandomState(0)
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Y, _, _ = generate_toy_data(3, 10, (8, 8), random_state=rng) # wide array
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spca_lars = SparsePCA(n_components=3, method="lars", alpha=alpha, random_state=0)
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spca_lars.fit(Y)
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# Test that CD gives similar results
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spca_lasso = SparsePCA(n_components=3, method="cd", random_state=0, alpha=alpha)
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spca_lasso.fit(Y)
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assert_array_almost_equal(spca_lasso.components_, spca_lars.components_)
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@if_safe_multiprocessing_with_blas
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def test_fit_transform_parallel():
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alpha = 1
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rng = np.random.RandomState(0)
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Y, _, _ = generate_toy_data(3, 10, (8, 8), random_state=rng) # wide array
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spca_lars = SparsePCA(n_components=3, method="lars", alpha=alpha, random_state=0)
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spca_lars.fit(Y)
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U1 = spca_lars.transform(Y)
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# Test multiple CPUs
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spca = SparsePCA(
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n_components=3, n_jobs=2, method="lars", alpha=alpha, random_state=0
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).fit(Y)
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U2 = spca.transform(Y)
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assert not np.all(spca_lars.components_ == 0)
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assert_array_almost_equal(U1, U2)
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def test_transform_nan():
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# Test that SparsePCA won't return NaN when there is 0 feature in all
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# samples.
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rng = np.random.RandomState(0)
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Y, _, _ = generate_toy_data(3, 10, (8, 8), random_state=rng) # wide array
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Y[:, 0] = 0
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estimator = SparsePCA(n_components=8)
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assert not np.any(np.isnan(estimator.fit_transform(Y)))
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def test_fit_transform_tall():
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rng = np.random.RandomState(0)
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Y, _, _ = generate_toy_data(3, 65, (8, 8), random_state=rng) # tall array
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spca_lars = SparsePCA(n_components=3, method="lars", random_state=rng)
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U1 = spca_lars.fit_transform(Y)
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spca_lasso = SparsePCA(n_components=3, method="cd", random_state=rng)
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U2 = spca_lasso.fit(Y).transform(Y)
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assert_array_almost_equal(U1, U2)
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def test_initialization():
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rng = np.random.RandomState(0)
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U_init = rng.randn(5, 3)
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V_init = rng.randn(3, 4)
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model = SparsePCA(
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n_components=3, U_init=U_init, V_init=V_init, max_iter=0, random_state=rng
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)
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model.fit(rng.randn(5, 4))
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expected_components = V_init / np.linalg.norm(V_init, axis=1, keepdims=True)
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expected_components = svd_flip(u=expected_components.T, v=None)[0].T
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assert_allclose(model.components_, expected_components)
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def test_mini_batch_correct_shapes():
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rng = np.random.RandomState(0)
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X = rng.randn(12, 10)
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pca = MiniBatchSparsePCA(n_components=8, max_iter=1, random_state=rng)
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U = pca.fit_transform(X)
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assert pca.components_.shape == (8, 10)
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assert U.shape == (12, 8)
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# test overcomplete decomposition
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pca = MiniBatchSparsePCA(n_components=13, max_iter=1, random_state=rng)
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U = pca.fit_transform(X)
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assert pca.components_.shape == (13, 10)
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assert U.shape == (12, 13)
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# XXX: test always skipped
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@pytest.mark.skipif(True, reason="skipping mini_batch_fit_transform.")
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def test_mini_batch_fit_transform():
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alpha = 1
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rng = np.random.RandomState(0)
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Y, _, _ = generate_toy_data(3, 10, (8, 8), random_state=rng) # wide array
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spca_lars = MiniBatchSparsePCA(n_components=3, random_state=0, alpha=alpha).fit(Y)
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U1 = spca_lars.transform(Y)
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# Test multiple CPUs
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if sys.platform == "win32": # fake parallelism for win32
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import joblib
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_mp = joblib.parallel.multiprocessing
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joblib.parallel.multiprocessing = None
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try:
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spca = MiniBatchSparsePCA(
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n_components=3, n_jobs=2, alpha=alpha, random_state=0
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)
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U2 = spca.fit(Y).transform(Y)
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finally:
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joblib.parallel.multiprocessing = _mp
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else: # we can efficiently use parallelism
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spca = MiniBatchSparsePCA(n_components=3, n_jobs=2, alpha=alpha, random_state=0)
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U2 = spca.fit(Y).transform(Y)
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assert not np.all(spca_lars.components_ == 0)
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assert_array_almost_equal(U1, U2)
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# Test that CD gives similar results
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spca_lasso = MiniBatchSparsePCA(
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n_components=3, method="cd", alpha=alpha, random_state=0
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).fit(Y)
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assert_array_almost_equal(spca_lasso.components_, spca_lars.components_)
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def test_scaling_fit_transform():
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alpha = 1
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rng = np.random.RandomState(0)
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Y, _, _ = generate_toy_data(3, 1000, (8, 8), random_state=rng)
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spca_lars = SparsePCA(n_components=3, method="lars", alpha=alpha, random_state=rng)
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results_train = spca_lars.fit_transform(Y)
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results_test = spca_lars.transform(Y[:10])
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assert_allclose(results_train[0], results_test[0])
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def test_pca_vs_spca():
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rng = np.random.RandomState(0)
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Y, _, _ = generate_toy_data(3, 1000, (8, 8), random_state=rng)
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Z, _, _ = generate_toy_data(3, 10, (8, 8), random_state=rng)
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spca = SparsePCA(alpha=0, ridge_alpha=0, n_components=2)
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pca = PCA(n_components=2)
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pca.fit(Y)
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spca.fit(Y)
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results_test_pca = pca.transform(Z)
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results_test_spca = spca.transform(Z)
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assert_allclose(
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np.abs(spca.components_.dot(pca.components_.T)), np.eye(2), atol=1e-5
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)
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results_test_pca *= np.sign(results_test_pca[0, :])
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results_test_spca *= np.sign(results_test_spca[0, :])
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assert_allclose(results_test_pca, results_test_spca)
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@pytest.mark.parametrize("SPCA", [SparsePCA, MiniBatchSparsePCA])
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@pytest.mark.parametrize("n_components", [None, 3])
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def test_spca_n_components_(SPCA, n_components):
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rng = np.random.RandomState(0)
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n_samples, n_features = 12, 10
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X = rng.randn(n_samples, n_features)
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model = SPCA(n_components=n_components).fit(X)
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if n_components is not None:
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assert model.n_components_ == n_components
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else:
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assert model.n_components_ == n_features
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@pytest.mark.parametrize("SPCA", (SparsePCA, MiniBatchSparsePCA))
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@pytest.mark.parametrize("method", ("lars", "cd"))
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@pytest.mark.parametrize(
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"data_type, expected_type",
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(
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(np.float32, np.float32),
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(np.float64, np.float64),
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(np.int32, np.float64),
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(np.int64, np.float64),
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),
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)
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def test_sparse_pca_dtype_match(SPCA, method, data_type, expected_type):
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# Verify output matrix dtype
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n_samples, n_features, n_components = 12, 10, 3
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rng = np.random.RandomState(0)
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input_array = rng.randn(n_samples, n_features).astype(data_type)
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model = SPCA(n_components=n_components, method=method)
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transformed = model.fit_transform(input_array)
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assert transformed.dtype == expected_type
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assert model.components_.dtype == expected_type
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@pytest.mark.parametrize("SPCA", (SparsePCA, MiniBatchSparsePCA))
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@pytest.mark.parametrize("method", ("lars", "cd"))
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def test_sparse_pca_numerical_consistency(SPCA, method):
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# Verify numericall consistentency among np.float32 and np.float64
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rtol = 1e-3
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alpha = 2
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n_samples, n_features, n_components = 12, 10, 3
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rng = np.random.RandomState(0)
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input_array = rng.randn(n_samples, n_features)
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model_32 = SPCA(
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n_components=n_components, alpha=alpha, method=method, random_state=0
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)
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transformed_32 = model_32.fit_transform(input_array.astype(np.float32))
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model_64 = SPCA(
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n_components=n_components, alpha=alpha, method=method, random_state=0
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)
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transformed_64 = model_64.fit_transform(input_array.astype(np.float64))
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assert_allclose(transformed_64, transformed_32, rtol=rtol)
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assert_allclose(model_64.components_, model_32.components_, rtol=rtol)
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@pytest.mark.parametrize("SPCA", [SparsePCA, MiniBatchSparsePCA])
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def test_spca_feature_names_out(SPCA):
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"""Check feature names out for *SparsePCA."""
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rng = np.random.RandomState(0)
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n_samples, n_features = 12, 10
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X = rng.randn(n_samples, n_features)
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model = SPCA(n_components=4).fit(X)
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names = model.get_feature_names_out()
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estimator_name = SPCA.__name__.lower()
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assert_array_equal([f"{estimator_name}{i}" for i in range(4)], names)
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# TODO(1.6): remove in 1.6
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def test_spca_max_iter_None_deprecation():
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"""Check that we raise a warning for the deprecation of `max_iter=None`."""
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rng = np.random.RandomState(0)
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n_samples, n_features = 12, 10
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X = rng.randn(n_samples, n_features)
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warn_msg = "`max_iter=None` is deprecated in version 1.4 and will be removed"
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with pytest.warns(FutureWarning, match=warn_msg):
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MiniBatchSparsePCA(max_iter=None).fit(X)
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def test_spca_early_stopping(global_random_seed):
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"""Check that `tol` and `max_no_improvement` act as early stopping."""
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rng = np.random.RandomState(global_random_seed)
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n_samples, n_features = 50, 10
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X = rng.randn(n_samples, n_features)
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# vary the tolerance to force the early stopping of one of the model
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model_early_stopped = MiniBatchSparsePCA(
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max_iter=100, tol=0.5, random_state=global_random_seed
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).fit(X)
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model_not_early_stopped = MiniBatchSparsePCA(
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max_iter=100, tol=1e-3, random_state=global_random_seed
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).fit(X)
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assert model_early_stopped.n_iter_ < model_not_early_stopped.n_iter_
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# force the max number of no improvement to a large value to check that
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# it does help to early stop
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model_early_stopped = MiniBatchSparsePCA(
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max_iter=100, tol=1e-6, max_no_improvement=2, random_state=global_random_seed
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).fit(X)
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model_not_early_stopped = MiniBatchSparsePCA(
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max_iter=100, tol=1e-6, max_no_improvement=100, random_state=global_random_seed
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).fit(X)
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assert model_early_stopped.n_iter_ < model_not_early_stopped.n_iter_
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def test_equivalence_components_pca_spca(global_random_seed):
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"""Check the equivalence of the components found by PCA and SparsePCA.
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Non-regression test for:
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https://github.com/scikit-learn/scikit-learn/issues/23932
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"""
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rng = np.random.RandomState(global_random_seed)
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X = rng.randn(50, 4)
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n_components = 2
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pca = PCA(
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n_components=n_components,
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svd_solver="randomized",
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random_state=0,
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).fit(X)
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spca = SparsePCA(
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n_components=n_components,
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method="lars",
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ridge_alpha=0,
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alpha=0,
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random_state=0,
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).fit(X)
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assert_allclose(pca.components_, spca.components_)
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def test_sparse_pca_inverse_transform():
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"""Check that `inverse_transform` in `SparsePCA` and `PCA` are similar."""
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rng = np.random.RandomState(0)
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n_samples, n_features = 10, 5
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X = rng.randn(n_samples, n_features)
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n_components = 2
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spca = SparsePCA(
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n_components=n_components, alpha=1e-12, ridge_alpha=1e-12, random_state=0
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)
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pca = PCA(n_components=n_components, random_state=0)
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X_trans_spca = spca.fit_transform(X)
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X_trans_pca = pca.fit_transform(X)
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assert_allclose(
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spca.inverse_transform(X_trans_spca), pca.inverse_transform(X_trans_pca)
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)
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@pytest.mark.parametrize("SPCA", [SparsePCA, MiniBatchSparsePCA])
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def test_transform_inverse_transform_round_trip(SPCA):
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"""Check the `transform` and `inverse_transform` round trip with no loss of
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information.
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"""
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rng = np.random.RandomState(0)
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n_samples, n_features = 10, 5
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X = rng.randn(n_samples, n_features)
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n_components = n_features
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spca = SPCA(
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n_components=n_components, alpha=1e-12, ridge_alpha=1e-12, random_state=0
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)
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X_trans_spca = spca.fit_transform(X)
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||
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assert_allclose(spca.inverse_transform(X_trans_spca), X)
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