bloqade.lanes.heuristics.physical.movement.make_physical_placement_strategy

← Module overview

functionmake_physical_placement_strategy¶source

bloqade.lanes.heuristics.physical.movement.make_physical_placement_strategy

Signature

def make_physical_placement_strategy(*, move_solutions_per_layer: int = 3, search_budget: int | None = 300, strategy: SearchStrategyName = 'entropy', arch_spec: ArchSpec | None = None, return_moves: bool = True) -> PlacementStrategyABC

Public import paths

• from bloqade.lanes.transform.pipeline import make_physical_placement_strategy
• from bloqade.lanes.heuristics.physical import make_physical_placement_strategy

Build a physical placement strategy from user-facing search knobs.

Uses NoHomePlacementStrategy backed by the Rust NoHomeCzPlacement solver.

move_solutions_per_layer maps to k_candidates (candidate home sites per qubit in the Hungarian assignment). search_budget maps to max_expansions. lambda_lookahead is fixed at 0 because palindrome return always moves atoms back to their original home position, so future-layer proximity penalties carry no signal.

return_moves also selects mirrored solving: it wraps the strategy in PalindromePlacementStrategy and turns on backwards_search, since palindrome is what makes mirroring sound (see below).

.. warning::

On the palindrome path (return_moves=True, the default) with a home starting layout — atoms on their even/home words — move_solutions_per_layer has no effect. It maps to k_candidates, which feeds the no-home return assignment, and that phase never runs under palindrome: solve_nohome skips it whenever every atom already sits on a home site. Confirmed empirically — sweeping move_solutions_per_layer over 1, 3, 8 and 20 produces byte-identical move layers at 4, 6 and 8 atoms. The knob still applies when return_moves=False, or when atoms start off their home words.

The wider consequence is that palindrome reduces

NoHomePlacementStrategy

to a plain fixed-target router, so gamma, k_candidates, top_bus_signatures and bus_reward_rho are all inert on that path.

Parameters

Name	Type	Default	Description
move_solutions_per_layer	int	3
search_budget	int | None	300
strategy	SearchStrategyName	'entropy'
arch_spec	ArchSpec | None	None
return_moves	bool	True

Returns

PlacementStrategyABC

source