def test_delta_variance(self): """Tests if delta variance is correctly computed. """ S = self.S_2x3 C = self.C_2x2 D = self.D_2x3 ridge_factor = self.ridge_factor_05 sigma = self.sigma_05 a = self.a_1 crkr = CrKr(S, C, D, ridge_factor, sigma, a) new_s = np.array([[1, 1, 1]]) k = crkr._compute_k(new_s) K = crkr._compute_K() expected_dv = (a + ridge_factor - np.dot(k.T, np.dot(npla.inv(K + ridge_factor * C), k))) assert_true(np.allclose(expected_dv, crkr._delta_variance(k, K)))