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Decomposer

Bases: BaseModel

Configuration for breaking down larger problems into subproblems for DWave QPUs.

Attributes:

Name Type Description
size int, default=10

Nominal number of variables in each subproblem. The actual subproblem can be smaller depending on other parameters (e.g., min_gain).
min_gain Optional[float], default=None

Minimum required energy reduction threshold for including a variable in the subproblem. A variable is included only if flipping its value reduces the BQM energy by at least this amount. If None, no minimum gain is required.
rolling bool, default=True

Controls variable selection strategy for successive calls on the same problem:

  • True: Produces subproblems on different variables by rolling down the list of all variables sorted by decreasing impact
  • False: Always selects variables with the highest impact
rolling_history float, default=1.0

Fraction of the problem size (range 0.0 to 1.0) that participates in the rolling selection. Once this fraction of variables has been processed, subproblem unrolling is reset. Min: 0.0, Max: 1.0
silent_rewind bool, default=True

Controls behavior when resetting/rewinding the subproblem generator:

  • True: Silently rewind when the reset condition is met
  • False: Raises EndOfStream exception when rewinding
traversal Literal["energy", "bfs", "pfs"], default="energy"

Algorithm used to select a subproblem of size variables:

  • "energy": Selects the next size variables ordered by descending energy impact
  • "bfs": Uses breadth-first traversal seeded by the next variable in the energy impact list
  • "pfs": Uses priority-first traversal seeded by variables from the energy impact list, proceeding with the variable on the search boundary having the highest energy impact

min_gain class-attribute instance-attribute 

min_gain: float | None = None

rolling class-attribute instance-attribute 

rolling: bool = True

rolling_history class-attribute instance-attribute 

rolling_history: float = Field(default=1.0, ge=0.0, le=1.0)

silent_rewind class-attribute instance-attribute 

silent_rewind: bool = True

size class-attribute instance-attribute 

size: int = 10

traversal class-attribute instance-attribute 

traversal: Literal['energy', 'bfs', 'pfs'] = 'energy'