QSearchSynthesisPass

class QSearchSynthesisPass(heuristic_function=<bqskit.passes.search.heuristics.astar.AStarHeuristic object>, layer_generator=None, success_threshold=1e-08, cost=<bqskit.ir.opt.cost.functions.residuals.hilbertschmidt.HilbertSchmidtResidualsGenerator object>, max_layer=None, no_progress_layers_allowed=10, store_partial_solutions=False, partials_per_depth=25, instantiate_options={})[source]

Bases: SynthesisPass

A pass implementing the QSearch A* synthesis algorithm.

References

Davis, Marc G., et al. “Towards Optimal Topology Aware Quantum Circuit Synthesis.” 2020 IEEE International Conference on Quantum Computing and Engineering (QCE). IEEE, 2020.

__init__(heuristic_function=<bqskit.passes.search.heuristics.astar.AStarHeuristic object>, layer_generator=None, success_threshold=1e-08, cost=<bqskit.ir.opt.cost.functions.residuals.hilbertschmidt.HilbertSchmidtResidualsGenerator object>, max_layer=None, no_progress_layers_allowed=10, store_partial_solutions=False, partials_per_depth=25, instantiate_options={})[source]

Construct a search-based synthesis pass.

Parameters:

  • heuristic_function (HeuristicFunction) – The heuristic to guide search.

  • layer_generator (LayerGenerator | None) – The successor function to guide node expansion. If left as none, then a default will be selected before synthesis based on the target model’s gate set. (Default: None)

  • success_threshold (float) – The distance threshold that determines successful termintation. Measured in cost described by the cost function. (Default: 1e-8)

  • cost (CostFunctionGenerator) – The cost function that determines distance during synthesis. The goal of this synthesis pass is to implement circuits for the given unitaries that have a cost less than the success_threshold. (Default: HSDistance())

  • max_layer (int | None) – The maximum number of layers to append without success before termination. If left as None it will default to unlimited. (Default: None)

  • no_progress_layers_allowed (int) – The maximum number of layers allowed without improvement before a warning is issued to the user. (Default: 10)

  • store_partial_solutions (bool) – Whether to store partial solutions at different depths inside of the data dict. (Default: False)

  • partials_per_depth (int) – The maximum number of partials to store per search depth. No effect if store_partial_solutions is False. (Default: 25)

  • (dict[str (instantiate_options) – Any]): Options passed directly to circuit.instantiate when instantiating circuit templates. (Default: {})

Raises:

ValueError – If max_depth is nonpositive.

Attributes

name

The name of the pass.

Methods

execute(*args, **kwargs)

Map a function over iterable arguments in parallel.

get_citations()

Return the set of citations associated with this pass.

get_connectivity(_, data)

Retrieve the current connectivity of the circuit.

get_model(_, data)

Retrieve the machine model from the data dictionary.

get_placement(_, data)

Retrieve the logical to physical qubit map from the data dictionary.

get_target(_, data)

Retrieve the target from the data dictionary.

in_parallel(data)

Return true if pass is being executed in a parallel.

run(circuit, data)

Perform the pass's operation, see BasePass for more.

synthesize(utry, data)

Synthesize utry, see SynthesisPass for more.