def test_feedback_siso(self):
"""Test for correct SISO transfer function feedback."""
sys1 = TransferFunction([-1., 4.], [1., 3., 5.])
sys2 = TransferFunction([2., 3., 0.], [1., -3., 4., 0])
sys3 = sys1.feedback(sys2)
sys4 = sys1.feedback(sys2, 1)
np.testing.assert_allclose(sys3.num, [[[-1., 7., -16., 16., 0.]]])
np.testing.assert_allclose(sys3.den, [[[1., 0., -2., 2., 32., 0.]]])
np.testing.assert_allclose(sys4.num, [[[-1., 7., -16., 16., 0.]]])
np.testing.assert_allclose(sys4.den, [[[1., 0., 2., -8., 8., 0.]]])
def test_size_mismatch(self):
"""Test size mismacht"""
sys1 = ss2tf(rss(2, 2, 2))
# Different number of inputs
sys2 = ss2tf(rss(3, 1, 2))
with pytest.raises(ValueError):
TransferFunction.__add__(sys1, sys2)
# Different number of outputs
sys2 = ss2tf(rss(3, 2, 1))
with pytest.raises(ValueError):
TransferFunction.__add__(sys1, sys2)
# Inputs and outputs don't match
with pytest.raises(ValueError):
TransferFunction.__mul__(sys2, sys1)
# Feedback mismatch (MIMO not implemented)
with pytest.raises(NotImplementedError):
TransferFunction.feedback(sys2, sys1)