53 lines
1.6 KiB
Python
53 lines
1.6 KiB
Python
# Author: Christian Osendorfer <osendorf@gmail.com>
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# Alexandre Gramfort <alexandre.gramfort@inria.fr>
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# Licence: BSD3
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import numpy as np
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from sklearn.utils.testing import assert_true
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from sklearn.utils.testing import assert_raises
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from sklearn.utils.testing import assert_almost_equal
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from sklearn.decomposition import FactorAnalysis
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def test_factor_analysis():
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"""Test FactorAnalysis ability to recover the data covariance structure
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"""
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rng = np.random.RandomState(0)
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n_samples, n_features, n_components = 20, 5, 3
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# Some random settings for the generative model
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W = rng.randn(n_components, n_features)
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# latent variable of dim 3, 20 of it
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h = rng.randn(n_samples, n_components)
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# using gamma to model different noise variance
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# per component
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noise = rng.gamma(1, size=n_features) * rng.randn(n_samples, n_features)
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# generate observations
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# wlog, mean is 0
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X = np.dot(h, W) + noise
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fa = FactorAnalysis(n_components=n_components)
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fa.fit(X)
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X_t = fa.transform(X)
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assert_true(X_t.shape == (n_samples, n_components))
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assert_almost_equal(fa.loglike_[-1], fa.score(X).sum())
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# Make log likelihood increases at each iteration
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assert_true(np.all(np.diff(fa.loglike_) > 0.))
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# Sample Covariance
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scov = np.cov(X, rowvar=0., bias=1.)
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# Model Covariance
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mcov = fa.get_covariance()
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diff = np.sum(np.abs(scov - mcov)) / W.size
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assert_true(diff < 0.1, "Mean absolute difference is %f" % diff)
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fa = FactorAnalysis(n_components=n_components,
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noise_variance_init=np.ones(n_features))
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assert_raises(ValueError, fa.fit, X[:, :2])
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