def test_xy_mixer_type_error(self):
"""Tests that the XY mixer throws the correct error"""
graph = [(0, 1), (1, 2)]
with pytest.raises(ValueError, match=r"Input graph must be a nx.Graph object, got list"):
qaoa.xy_mixer(graph)
def test_xy_mixer_output(self, graph, target_hamiltonian):
"""Tests that the output of the XY mixer is correct"""
mixer_hamiltonian = qaoa.xy_mixer(graph)
mixer_coeffs = mixer_hamiltonian.coeffs
mixer_ops = [i.name for i in mixer_hamiltonian.ops]
mixer_wires = [i.wires for i in mixer_hamiltonian.ops]
target_coeffs = target_hamiltonian.coeffs
target_ops = [i.name for i in target_hamiltonian.ops]
target_wires = [i.wires for i in target_hamiltonian.ops]
assert mixer_coeffs == target_coeffs
assert mixer_ops == target_ops
assert mixer_wires == target_wires
class TestLayers:
"""Tests that the cost and mixer layers are being constructed properly"""
def test_mixer_layer_errors(self):
"""Tests that the mixer layer is throwing the correct errors"""
hamiltonian = [[1, 1], [1, 1]]
with pytest.raises(
ValueError,
match=r"hamiltonian must be of type pennylane.Hamiltonian"):
qaoa.mixer_layer(0.1, hamiltonian)
def test_cost_layer_errors(self):
"""Tests that the cost layer is throwing the correct errors"""
hamiltonian = [[1, 1], [1, 1]]
with pytest.raises(
ValueError,
match=r"hamiltonian must be of type pennylane.Hamiltonian"):
qaoa.cost_layer(0.1, hamiltonian)
hamiltonian = qml.Hamiltonian([1, 1], [qml.PauliZ(0), qml.PauliX(1)])
with pytest.raises(
ValueError,
match=
r"hamiltonian must be written only in terms of PauliZ and Identity gates"
):
qaoa.cost_layer(0.1, hamiltonian)
@pytest.mark.parametrize(
("mixer", "gates"), [[
qml.Hamiltonian([1, 1],
[qml.PauliX(0), qml.PauliX(1)]),
[qml.PauliRot(2, "X", wires=[0]),
qml.PauliRot(2, "X", wires=[1])]
],
[
qaoa.xy_mixer(Graph([(0, 1), (1, 2),
(2, 0)])),
[
qml.PauliRot(1, "XX", wires=[0, 1]),
qml.PauliRot(1, "YY", wires=[0, 1]),
qml.PauliRot(1, "XX", wires=[0, 2]),
qml.PauliRot(1, "YY", wires=[0, 2]),
qml.PauliRot(1, "XX", wires=[1, 2]),
qml.PauliRot(1, "YY", wires=[1, 2])
]
]])
def test_mixer_layer_output(self, mixer, gates):
"""Tests that the gates of the mixer layer are correct"""
alpha = 1
with qml._queuing.OperationRecorder() as rec:
qaoa.mixer_layer(alpha, mixer)
for i, j in zip(rec.operations, gates):
prep = [i.name, i.parameters, i.wires]
target = [j.name, j.parameters, j.wires]
assert prep == target
@pytest.mark.parametrize(
("cost", "gates"), [[
qml.Hamiltonian([1, 1],
[qml.PauliZ(0), qml.PauliZ(1)]),
[qml.PauliRot(2, "Z", wires=[0]),
qml.PauliRot(2, "Z", wires=[1])]
],
[
qaoa.maxcut(Graph([(0, 1), (1, 2),
(2, 0)]))[0],
[
qml.PauliRot(1, "ZZ", wires=[0, 1]),
qml.PauliRot(1, "ZZ", wires=[0, 2]),
qml.PauliRot(1, "ZZ", wires=[1, 2])
]
]])
def test_cost_layer_output(self, cost, gates):
"""Tests that the gates of the cost layer is correct"""
gamma = 1
with qml._queuing.OperationRecorder() as rec:
qaoa.cost_layer(gamma, cost)
for i, j in zip(rec.operations, gates):
prep = [i.name, i.parameters, i.wires]
target = [j.name, j.parameters, j.wires]
assert prep == target
