def get_expectation_values_for_qubit_operator(
backend_specs: Specs,
circuit: Union[str, Circuit],
qubit_operator: Union[str, SymbolicOperator],
):
"""Measure the expection values of the terms in an input operator with respect to the state prepared by the input
circuit on the backend described by the backend_specs. The results are serialized into a JSON under the
file: "expectation-values.json"
ARGS:
backend_specs (Union[dict, str]): The backend on which to run the quantum circuit
circuit (Union[str, Circuit]): The circuit that prepares the state to be measured
qubit_operator (Union[str, SymbolicOperator]): The operator to measure
"""
if isinstance(circuit, str):
circuit = load_circuit(circuit)
if isinstance(qubit_operator, str):
qubit_operator = load_qubit_operator(qubit_operator)
if isinstance(backend_specs, str):
backend_specs = json.loads(backend_specs)
backend = create_object(backend_specs)
expectation_values = backend.get_expectation_values(
circuit, qubit_operator)
save_expectation_values(expectation_values, "expectation-values.json")
def get_expectation_values_for_qubit_operator(
backend_specs: Specs,
circuit: Union[str, Circuit, Dict],
qubit_operator: Union[str, SymbolicOperator, Dict],
):
"""Measure the expectation values of the terms in an input operator with respect to
the state prepared by the input circuit on the backend described by the
`backend_specs`. The results are serialized into a JSON under the file:
"expectation-values.json"
Args:
backend_specs: The backend on which to run the quantum circuit
circuit: The circuit that prepares the state to be measured
qubit_operator: The operator to measure
"""
if isinstance(circuit, str):
circuit = load_circuit(circuit)
elif isinstance(circuit, dict):
circuit = circuit_from_dict(circuit)
if isinstance(qubit_operator, str):
qubit_operator = load_qubit_operator(qubit_operator)
elif isinstance(qubit_operator, dict):
qubit_operator = convert_dict_to_qubitop(qubit_operator)
if isinstance(backend_specs, str):
backend_specs = json.loads(backend_specs)
backend = cast(QuantumBackend, create_object(backend_specs))
estimation_tasks = [
EstimationTask(qubit_operator, circuit, backend.n_samples)
]
expectation_values = estimate_expectation_values_by_averaging(
backend, estimation_tasks)
save_expectation_values(expectation_values[0], "expectation-values.json")
def expectation_values_from_rdms(
interactionrdm: str,
qubit_operator: str,
sort_terms: bool = False,
):
operator = load_qubit_operator(qubit_operator)
rdms = load_interaction_rdm(interactionrdm)
expecval = get_expectation_values_from_rdms(rdms, operator, sort_terms=sort_terms)
save_expectation_values(expecval, "expectation_values.json")
def test_expectation_values_io():
expectation_values = np.array([0.0, 0.0, -1.0])
correlations = []
correlations.append(np.array([[1.0, -1.0], [-1.0, 1.0]]))
correlations.append(np.array([[1.0]]))
estimator_covariances = []
estimator_covariances.append(np.array([[0.1, -0.1], [-0.1, 0.1]]))
estimator_covariances.append(np.array([[0.1]]))
expectation_values_object = ExpectationValues(expectation_values,
correlations,
estimator_covariances)
save_expectation_values(expectation_values_object,
"expectation_values.json")
expectation_values_object_loaded = load_expectation_values(
"expectation_values.json")
assert np.allclose(
expectation_values_object.values,
expectation_values_object_loaded.values,
)
assert len(expectation_values_object.correlations) == len(
expectation_values_object_loaded.correlations)
assert len(expectation_values_object.estimator_covariances) == len(
expectation_values_object_loaded.estimator_covariances)
for i in range(len(expectation_values_object.correlations)):
assert np.allclose(
expectation_values_object.correlations[i],
expectation_values_object_loaded.correlations[i],
)
for i in range(len(expectation_values_object.estimator_covariances)):
assert np.allclose(
expectation_values_object.estimator_covariances[i],
expectation_values_object_loaded.estimator_covariances[i],
)
remove_file_if_exists("expectation_values.json")
def expectation_values_from_rdms_for_qubitoperator_list(
interactionrdm: str,
qubit_operator_list: str,
sort_terms: bool = False):
"""Computes expectation values of Pauli strings in a list of QubitOperator given a
fermionic InteractionRDM from OpenFermion. All the expectation values for the
operators in the list are written to file in a single ExpectationValues object in the
same order the operators came in.
ARGS:
interactionrdm (str): The name of the file containing the interaction RDM to
use for the expectation values computation
qubitoperator_list (str): The name of the file containing the list of qubit operators
to compute the expectation values for in the form of OpenFermion QubitOperator objects
sort_terms (bool): whether or not each input qubit operator needs to be sorted before
calculating expectations
"""
operator_list = load_qubit_operator_set(qubit_operator_list)
rdms = load_interaction_rdm(interactionrdm)
expecval = get_expectation_values_from_rdms_for_qubitoperator_list(
rdms, operator_list, sort_terms=sort_terms)
save_expectation_values(expecval, "expectation_values.json")
def get_expectation_values_for_qubit_operator(backend_specs, circuit, qubit_operator):
circuit = load_circuit(circuit)
qubit_operator = load_qubit_operator(qubit_operator)
backend = create_object(json.loads(backend_specs))
expectation_values = backend.get_expectation_values(circuit, qubit_operator)
save_expectation_values(expectation_values, "expectation-values.json")
