Estimator
class qiskit.primitives.Estimator(*, options=None)
Bases: BaseEstimator[PrimitiveJob[EstimatorResult]]
Reference implementation of BaseEstimator (V1).
Run Options
- shots (None or int) – The number of shots. If None, it calculates the expectation values with full state vector simulation. Otherwise, it samples from normal distributions with standard errors as standard deviations using normal distribution approximation.
- seed (np.random.Generator or int) – Set a fixed seed or generator for the normal distribution. If shots is None, this option is ignored.
The result of this class is exact if the circuit contains only unitary operations. On the other hand, the result could be stochastic if the circuit contains a non-unitary operation such as a reset for a some subsystems. The stochastic result can be made reproducible by setting seed, e.g., Estimator(options={"seed":123}).
The class qiskit.primitives.estimator.Estimator is deprecated as of qiskit 1.2. It will be removed no earlier than 3 months after the release date. All implementations of the BaseEstimatorV1 interface have been deprecated in favor of their V2 counterparts. The V2 alternative for the Estimator class is StatevectorEstimator.
Parameters
options (dict | None) – Default options.
Raises
QiskitError – if some classical bits are not used for measurements.
Attributes
options
Return options values for the estimator.
Returns
options
Methods
run
run(circuits, observables, parameter_values=None, **run_options)
Run the job of the estimation of expectation value(s).
circuits, observables, and parameter_values should have the same length. The i-th element of the result is the expectation of observable
obs = observables[i]for the state prepared by
circ = circuits[i]with bound parameters
values = parameter_values[i]Parameters
- circuits (Sequence[QuantumCircuit] | QuantumCircuit) – one or more circuit objects.
- observables (Sequence[BaseOperator | str] | BaseOperator | str) – one or more observable objects. Several formats are allowed; importantly,
strshould follow the string representation format forPauliobjects. - parameter_values (Sequence[Sequence[float]] | Sequence[float] | float | None) – concrete parameters to be bound.
- run_options – runtime options used for circuit execution.
Returns
The job object of EstimatorResult.
Raises
- TypeError – Invalid argument type given.
- ValueError – Invalid argument values given.
Return type
T
set_options
set_options(**fields)
Set options values for the estimator.
Parameters
**fields – The fields to update the options