class TestKrausOps:
"""Unit tests for the method `_get_kraus_ops()`"""
unitary_ops = [(qml.PauliX, np.array([[0, 1], [1, 0]])),
(qml.Hadamard,
np.array([[INV_SQRT2, INV_SQRT2], [INV_SQRT2,
-INV_SQRT2]])),
(qml.CNOT,
np.array([[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 0, 1],
[0, 0, 1, 0]]))]
@pytest.mark.parametrize("ops", unitary_ops)
def test_unitary_kraus(self, ops):
"""Tests that matrices of non-diagonal unitary operations are retrieved correctly"""
dev = qml.device('default.mixed', wires=2)
assert np.allclose(dev._get_kraus(ops[0]), [ops[1]])
diagonal_ops = [(qml.PauliZ(wires=0), np.array([1, -1])),
(qml.CZ(wires=[0, 1]), np.array([1, 1, 1, -1]))]
@pytest.mark.parametrize("ops", diagonal_ops)
def test_diagonal_kraus(self, ops):
"""Tests that matrices of non-diagonal unitary operations are retrieved correctly"""
dev = qml.device('default.mixed', wires=2)
assert np.allclose(dev._get_kraus(ops[0]), ops[1])
p = 0.5
K0 = np.sqrt(1 - p) * np.eye(2)
K1 = np.sqrt(p / 3) * np.array([[0, 1], [1, 0]])
K2 = np.sqrt(p / 3) * np.array([[0, -1j], [1j, 0]])
K3 = np.sqrt(p / 3) * np.array([[1, 0], [0, -1]])
channel_ops = [(qml.AmplitudeDamping(p, wires=0), [
np.diag([1, np.sqrt(1 - p)]),
np.sqrt(p) * np.array([[0, 1], [0, 0]])
]), (qml.DepolarizingChannel(p, wires=0), [K0, K1, K2, K3])]
@pytest.mark.parametrize("ops", channel_ops)
def test_channel_kraus(self, ops):
"""Tests that krause matrices of non-unitary channels are retrieved correctly"""
dev = qml.device('default.mixed', wires=1)
assert np.allclose(dev._get_kraus(ops[0]), ops[1])
def circuit(p):
qml.RX(angle, wires=0)
qml.DepolarizingChannel(p, wires=0)
return qml.expval(qml.PauliZ(0))
def depolarizing_circuit(p):
qml.Hadamard(wires=0)
qml.CNOT(wires=[0, 1])
qml.DepolarizingChannel(p, wires=0)
qml.DepolarizingChannel(p, wires=1)
return qml.expval(qml.PauliZ(0) @ qml.PauliZ(1))
def noisy_operations(damp_factor, depo_factor, flip_prob):
qml.AmplitudeDamping(damp_factor, wires=0)
qml.DepolarizingChannel(depo_factor, wires=0)
qml.BitFlip(flip_prob, wires=0)