def test_compare_covar_type(): # We can compare the 'full' precision with the other cov_type if we apply # 1 iter of the M-step (done during _initialize_parameters). rng = np.random.RandomState(0) rand_data = RandomData(rng, scale=7) X = rand_data.X['full'] n_components = rand_data.n_components for prior_type in PRIOR_TYPE: # Computation of the full_covariance bgmm = BayesianGaussianMixture( weight_concentration_prior_type=prior_type, n_components=2 * n_components, covariance_type='full', max_iter=1, random_state=0, tol=1e-7) bgmm._check_initial_parameters(X) bgmm._initialize_parameters(X, np.random.RandomState(0)) full_covariances = ( bgmm.covariances_ * bgmm.degrees_of_freedom_[:, np.newaxis, np.newaxis]) # Check tied_covariance = mean(full_covariances, 0) bgmm = BayesianGaussianMixture( weight_concentration_prior_type=prior_type, n_components=2 * n_components, covariance_type='tied', max_iter=1, random_state=0, tol=1e-7) bgmm._check_initial_parameters(X) bgmm._initialize_parameters(X, np.random.RandomState(0)) tied_covariance = bgmm.covariances_ * bgmm.degrees_of_freedom_ assert_almost_equal(tied_covariance, np.mean(full_covariances, 0)) # Check diag_covariance = diag(full_covariances) bgmm = BayesianGaussianMixture( weight_concentration_prior_type=prior_type, n_components=2 * n_components, covariance_type='diag', max_iter=1, random_state=0, tol=1e-7) bgmm._check_initial_parameters(X) bgmm._initialize_parameters(X, np.random.RandomState(0)) diag_covariances = (bgmm.covariances_ * bgmm.degrees_of_freedom_[:, np.newaxis]) assert_almost_equal(diag_covariances, np.array([np.diag(cov) for cov in full_covariances])) # Check spherical_covariance = np.mean(diag_covariances, 0) bgmm = BayesianGaussianMixture( weight_concentration_prior_type=prior_type, n_components=2 * n_components, covariance_type='spherical', max_iter=1, random_state=0, tol=1e-7) bgmm._check_initial_parameters(X) bgmm._initialize_parameters(X, np.random.RandomState(0)) spherical_covariances = bgmm.covariances_ * bgmm.degrees_of_freedom_ assert_almost_equal( spherical_covariances, np.mean(diag_covariances, 1))