Expectation

class pulser.backend.Expectation(operator, *, evaluation_times=None, tag_suffix=None, default_aggregation_method=AggregationMethod.MEAN)

Bases: Observable

Stores the expectation of the given operator on the current state.

Parameters:

  • evaluation_times (Sequence[float] | None, default: None) – The relative times at which to compute the expectation value. If left as None, uses the default_evaluation_times of the backend’s EmulationConfig.

  • operator (Operator) – The operator to measure. If its type is not the backend’s operator type, it is automatically converted when the config is given to the backend, provided it was created via Operator.from_operator_repr().

  • tag_suffix (str | None, default: None) – An optional suffix to append to the tag. Needed if multiple instances of the same observable are given to the same EmulationConfig.

  • default_aggregation_method (AggregationMethod, default: <AggregationMethod.MEAN: 2>) – How to combine the values of this observable from multiple results.

Attributes

default_aggregation_method

How the values from multiple results are combined.

tag

Label for the observable, used to index the Results object.

uuid

A universal unique identifier for this instance.

evaluation_times

Methods

apply

Calculates the observable to store in the Results.

Signatures

apply(*, state, **kwargs)

Calculates the observable to store in the Results.

Return type:

Any

property default_aggregation_method: AggregationMethod

How the values from multiple results are combined.

property tag: str

Label for the observable, used to index the Results object.

Within a Results instance, all computed observables must have different tags.

Returns:

The tag of the observable.

property uuid: UUID

A universal unique identifier for this instance.