def test_aer_placed_expectation() -> None:
# bug TKET-695
n_qbs = 3
c = Circuit(n_qbs, n_qbs)
c.X(0)
c.CX(0, 2)
c.CX(1, 2)
c.H(1)
# c.measure_all()
b = AerBackend()
operator = QubitPauliOperator({
QubitPauliString(Qubit(0), Pauli.Z): 1.0,
QubitPauliString(Qubit(1), Pauli.X): 0.5,
})
assert b.get_operator_expectation_value(c, operator) == (-0.5 + 0j)
with open(os.path.join(sys.path[0], "ibmqx2_properties.pickle"),
"rb") as f:
properties = pickle.load(f)
noise_model = NoiseModel.from_backend(properties)
noise_b = AerBackend(noise_model)
with pytest.raises(RuntimeError) as errorinfo:
noise_b.get_operator_expectation_value(c, operator)
assert "not supported with noise model" in str(errorinfo.value)
c.rename_units({Qubit(1): Qubit("node", 1)})
with pytest.raises(ValueError) as errorinfoCirc:
b.get_operator_expectation_value(c, operator)
assert "default register Qubits" in str(errorinfoCirc.value)
# Define the measurement operator:
xxi = QubitPauliString({Qubit(0): Pauli.X, Qubit(1): Pauli.X})
zzz = QubitPauliString({
Qubit(0): Pauli.Z,
Qubit(1): Pauli.Z,
Qubit(2): Pauli.Z
})
op = QubitPauliOperator({xxi: -1.8, zzz: 0.7j})
# Run on the backend:
backend = AerBackend()
backend.compile_circuit(c)
exp = backend.get_operator_expectation_value(c, op)
print(exp)
# ## `pytket.extensions.qiskit.AerBackend`
# `AerBackend` wraps up the `qasm_simulator` from the Qiskit Aer package. It supports an extremely flexible set of circuits and uses many effective simulation methods making it a great all-purpose sampling simulator.
#
# Unique features:
# - supports mid-circuit measurement and OpenQASM-style conditional gates;
# - encompasses a variety of underlying simulation methods and automatically selects the best one for each circuit (including statevector, density matrix, (extended) stabilizer and matrix product state);
# - can be provided with a `qiskit.providers.Aer.noise.NoiseModel` on instantiation to perform a noisy simulation.
# Useful features:
# - support for fast expectation value calculations according to `QubitPauliString`s or `QubitPauliOperator`s.
from pytket import Circuit