test_graph_lasso.py 文件源码

def test_graph_lasso_iris_singular():
    # Small subset of rows to test the rank-deficient case
    # Need to choose samples such that none of the variances are zero
    indices = np.arange(10, 13)

    # Hard-coded solution from R glasso package for alpha=0.01
    cov_R = np.array([
        [0.08, 0.056666662595, 0.00229729713223, 0.00153153142149],
        [0.056666662595, 0.082222222222, 0.00333333333333, 0.00222222222222],
        [0.002297297132, 0.003333333333, 0.00666666666667, 0.00009009009009],
        [0.001531531421, 0.002222222222, 0.00009009009009, 0.00222222222222]
    ])
    icov_R = np.array([
        [24.42244057, -16.831679593, 0.0, 0.0],
        [-16.83168201, 24.351841681, -6.206896552, -12.5],
        [0.0, -6.206896171, 153.103448276, 0.0],
        [0.0, -12.499999143, 0.0, 462.5]
    ])
    X = datasets.load_iris().data[indices, :]
    emp_cov = empirical_covariance(X)
    for method in ('cd', 'lars'):
        cov, icov = graph_lasso(emp_cov, alpha=0.01, return_costs=False,
                                mode=method)
        assert_array_almost_equal(cov, cov_R, decimal=5)
        assert_array_almost_equal(icov, icov_R, decimal=5)