def test_pstringcollection_expectation_from_measurements_qubit_indices():
measurements = MeasurementResult([[0, 0], [0, 0], [0, 1], [0, 1]],
qubit_indices=(1, 5))
pset = PauliStringCollection(
PauliString(spec="Z", coeff=-2.0, support=(1, )))
assert np.isclose(pset._expectation_from_measurements(measurements), -2.0)
pset = PauliStringCollection(
PauliString(spec="Z", coeff=-2.0, support=(5, )))
assert np.isclose(pset._expectation_from_measurements(measurements), 0.0)
def test_pstringcollection_expectation_from_measurements():
measurements = MeasurementResult([[0, 0], [0, 0], [0, 1], [0, 1]])
pset = PauliStringCollection(PauliString(spec="ZI", coeff=-2.0),
PauliString(spec="IZ", coeff=5.0))
assert np.isclose(pset._expectation_from_measurements(measurements), -2.0)
measurements = MeasurementResult([[1, 0], [1, 0], [0, 1], [0, 1]])
pset = PauliStringCollection(PauliString(spec="ZI", coeff=-2.0),
PauliString(spec="IZ", coeff=5.0))
assert np.isclose(pset._expectation_from_measurements(measurements), 0.0)