def test_apply_state_vector(self, nr_wires, tol):
"""Tests that we correctly apply a `QubitStateVector` operation for the root state"""
dev = qml.device("default.mixed", wires=nr_wires)
dim = 2 ** nr_wires
state = np.array([np.exp(1j * 2 * np.pi * n / dim) / np.sqrt(dim) for n in range(dim)])
dev.apply([QubitStateVector(state, wires=range(nr_wires))])
assert np.allclose(dev.state, root_state(nr_wires), atol=tol, rtol=0)
def test_raise_order_error_qubit_state(self):
"""Tests that an error is raised if a state is prepared after QubitStateVector has been
applied"""
dev = qml.device("default.mixed", wires=1)
state = np.array([1, 0])
ops = [PauliX(0), QubitStateVector(state, wires=0)]
with pytest.raises(DeviceError, match="Operation"):
dev.apply(ops)
def test_apply_state_vector_wires(self, tol):
"""Tests that we correctly apply a `QubitStateVector` operation for the root state when
wires are passed as an ordered list"""
nr_wires = 3
dev = qml.device("default.mixed", wires=[0, 1, 2])
dim = 2 ** nr_wires
state = np.array([np.exp(1j * 2 * np.pi * n / dim) / np.sqrt(dim) for n in range(dim)])
dev.apply([QubitStateVector(state, wires=[0, 1, 2])])
assert np.allclose(dev.state, root_state(nr_wires), atol=tol, rtol=0)