qrunch.quantum.groupers.qubit_wise

Module containing the qubit-wise closest grouper based on distance-between-Paulis heuristic.

Classes

QubitWiseGrouper

Grouper that uses a distance-between-Paulis heuristic for qubit-wise commutation.

QubitWiseGrouperOptions

Options for the QubitWiseGrouper.
class QubitWiseGrouper

Bases: MeasurementGrouper

Grouper that uses a distance-between-Paulis heuristic for qubit-wise commutation.

This grouper groups Pauli strings by measuring the “distance” between them based on qubit-wise compatibility. Pauli strings that are closer (more compatible) are grouped together, allowing measurement in the same basis.

The method is inherently qubit-wise, meaning it considers commutation on a per-qubit basis rather than global commutation of the entire Pauli string.

__init__(shot_distributor: ShotDistributor | None = None, options: QubitWiseGrouperOptions | None = None) → None

Initialize an instance of the QubitWiseGrouper.

Parameters:

  • shot_distributor (ShotDistributor | None) – Optional custom shot distributor to use for distributing shots among the groups.

  • options (QubitWiseGrouperOptions | None) – Options for the qubit-wise grouper.

Return type:

None

change_shot_distributor(shot_distributor: ShotDistributor) → MeasurementGrouper | None

Change shot distributor.

Parameters:

shot_distributor (ShotDistributor)

Return type:

MeasurementGrouper | None

group(pauli_sums: Sequence[HermitianPauliSum], shots: int | None, circuit: Circuit | None = None) → tuple[MeasurementGroup, ...]

Group Pauli strings using distance-between-Paulis heuristic.

Parameters:

  • pauli_sums (Sequence[HermitianPauliSum]) – Pauli sums to group.

  • shots (int | None) – Number of shots to distribute among the groups.

  • circuit (Circuit | None) – Circuit for the pauli sums to be measured on. Not used for this grouper.

Return type:

tuple[MeasurementGroup, …]

validate_shots_type(shots_type: Type[int | ShotsPerGroup | None]) → list[str]

Validate that the grouper supports the given shots type. Return a list of error messages if not supported.

Parameters:

shots_type (Type[int | ShotsPerGroup | None])

Return type:

list[str]

class QubitWiseGrouperOptions

Bases: DataclassPublicAPI

Options for the QubitWiseGrouper.

Parameters:

saturate_groups – If True, the groups are saturated with all compatible Pauli strings after grouping. (default=False)

__init__(*, saturate_groups: bool = False) → None
Parameters:

saturate_groups (bool)

Return type:

None

saturate_groups: bool = False