Observable

class pulser.backend.Observable(*, evaluation_times=None, tag_suffix=None)

Bases: Callback

The Observable abstract base class.

Parameters:

• evaluation_times (Sequence[float] | None, default: None) – The times at which to add a result to Results. If left as None, uses the default_evaluation_times of the backend’s EmulationConfig.

• 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.

Attributes

tag	Label for the observable, used to index the Results object.
uuid	A universal unique identifier for this instance.

Methods

apply

Calculates the observable to store in the Results.

Signatures

abstract apply(*, config, state, hamiltonian)

Calculates the observable to store in the Results.

Parameters:

• config (EmulationConfig) – The config object passed to the backend.

• state (State) – The current state.

• hamiltonian (Operator) – The Hamiltonian at this time.

Return type:

Any

Returns:

The result to put in Results.

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.