def test_dynamics_single_input():
"""Test dynamics equation with single input."""
a = np.array([[1.0, 2.0], [0.0, 1.0]])
b = np.array([[1.0], [3.0]])
c = np.zeros((1, 2))
s = StateSpace(a, b, c)
assert np.all(s.dynamics([1.0, 1.0], [1.0]) == np.array([4.0, 4.0]))
def test_output_mimo():
"""Test output equation with multiple inputs, multiple outputs."""
a = np.zeros((2, 2))
b = np.zeros((2, 2))
c = np.eye(2)
d = np.eye(2)
s = StateSpace(a, b, c, d)
assert np.all(s.output([1.0, 1.0], [2.0, 3.0]) == np.array([3.0, 4.0]))
def test_output_miso():
"""Test output equation with multiple inputs, single output."""
a = np.zeros((2, 2))
b = np.zeros((2, 2))
c = np.array([[1.0, 1.0]])
d = np.array([[2.0, 3.0]])
s = StateSpace(a, b, c, d)
assert np.all(s.output([1.0, 1.0], [1.0, 1.0]) == np.array([7.0]))
def test_output_siso():
"""Test output equation with single input, single output."""
a = np.zeros((2, 2))
b = np.zeros((2, 1))
c = np.array([[1.0, 1.0]])
d = np.array([[2.0]])
s = StateSpace(a, b, c, d)
assert s.output([1.0, 1.0], [1.0]) == np.array([4.0])
def test_auto_feedthrough_matrix():
"""Test if a zero feedthrough matrix is created if none specified."""
a = np.zeros((2, 2))
b = np.zeros((2, 3))
c = np.zeros((4, 2))
s = StateSpace(a, b, c)
assert s.d.shape == (4, 3)
def test_invalid_output_matrix_dimensions():
"""Test exception if C and A have different number of columns."""
a = np.zeros((2, 2))
b = np.zeros((2, 1))
c = np.zeros((1, 3))
with pytest.raises(ValueError) as excinfo:
StateSpace(a, b, c)
assert "Invalid matrix dimensions" in str(excinfo.value)
def test_invalid_state_matrix_dimensions():
"""Test exception if A is not square."""
a = np.zeros((2, 1))
b = np.zeros((2, 1))
c = np.zeros((1, 2))
with pytest.raises(ValueError) as excinfo:
StateSpace(a, b, c)
assert "Invalid matrix dimensions" in str(excinfo.value)
def test_invalid_feedthrough_matrix_dimensions():
"""Test exception if D does not match to B and C."""
a = np.zeros((2, 2))
b = np.zeros((2, 3))
c = np.zeros((4, 2))
d = np.zeros((4, 2))
with pytest.raises(ValueError) as excinfo:
StateSpace(a, b, c, d)
assert "Invalid matrix dimensions" in str(excinfo.value)
def test_human_friendly_form():
"""Test the __str__() method of a StateSpace object."""
a = np.array([[1.0, 2.0], [0.0, 1.0]])
b = np.array([[1.0, 2.0], [3.0, 2.0]])
c = np.zeros((1, 2))
s = StateSpace(a, b, c)
reference = \
"LTI discrete-time system.\n\n" \
"State matrix A:\n" \
"[[ 1. 2.]\n" \
" [ 0. 1.]]\n\n" \
"Input matrix B:\n" \
"[[ 1. 2.]\n" \
" [ 3. 2.]]\n\n" \
"Output matrix C:\n" \
"[[ 0. 0.]]\n\n" \
"Feedthrough matrix D:\n" \
"[[ 0. 0.]]\n"
assert s.__str__() == reference