def test_invertible_arma(self): arma = Arma([0.5, 0.3], [1.1, 0.6, 0.1]) self.assertTrue(arma.is_invertible())
def test_noninvertible_arma(self): arma = Arma([1.1], [-0.6, -0.55]) self.assertFalse(arma.is_invertible())
def test_critical_ma_counts_as_not_invertible(self): arma = Arma([], [1.0]) self.assertFalse(arma.is_invertible())
def test_noninvertible_pure_ma(self): arma = Arma([], [-1.1]) self.assertFalse(arma.is_invertible())
def test_invertible_pure_ma(self): arma = Arma([], [1.1, 0.6, 0.1]) self.assertTrue(arma.is_invertible())
def test_pure_ar_is_invertible(self): rng = default_rng(1) arma = Arma(rng.normal(size=4), []) self.assertTrue(arma.is_invertible())