def test_briggs_helper_function(self): np.random.seed(1234) for a in np.random.randn(10) + 1j * np.random.randn(10): for k in range(5): x_observed = _matfuncs_inv_ssq._briggs_helper_function(a, k) x_expected = a ** np.exp2(-k) - 1 assert_allclose(x_observed, x_expected)