pygsti.algorithms.grasp.run_grasp

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pygsti.algorithms.grasp.run_grasp#

run_grasp(elements, greedy_score_fn, rcl_fn, local_score_fn, get_neighbors_fn, final_score_fn, iterations, feasible_threshold=None, feasible_fn=None, initial_elements=None, seed=None, verbosity=0)#

Perform GRASP to come up with an optimal feasible set of elements.

Parameters:

  • elements (list) – A list containing some representation of the elements that can be used by the various score functions.

  • greedy_score_fn (callable) – Function that takes a sublist of elements and returns a score to minimize that is comparable with other scores. Used by the greedy construction to construct the initial feasible subset.

  • rcl_fn (callable) – Function that takes a list of sublists of elements (that is, a list of candidate partial solutions) and returns the indices within that list of partial solutions to be included in the restricted candidate list.

  • local_score_fn (callable) – Function that takes a sublist of elements and returns a score to minimize that is comparable with other scores. Used by the local search to find a locally optimal feasible subset.

  • get_neighbors_fn (callable) – Function that takes a binary vector indicating which members of elements are included in the current solution and returns a list of binary vectors indicating which potential solutions are in the neighborhood of the current solution for the purposes of local optimization.

  • final_score_fn (callable) – Function that takes a sublist of elements and returns a score to minimize that is comparable with other scores. Used to compare the solutions from various iterations in order to choose an optimum.

  • iterations (int) – How many iterations of greedy construction followed by local search to perform.

  • feasible_threshold (score) – A value comparable with the return value of the various score functions against which a score may be compared to test if the solution is feasible (the solution is feasible iff solnScore < feasible_threshold). Overrides feasible_fn if set to a value other than None.

  • feasible_fn (callable) – Function that takes a sublist of elements defining a potential solution and returns True if that solution is feasible (otherwise should return False). Not used if feasible_threshold is not None.

  • initial_elements (numpy.array) – Binary vector with 1s at indices corresponding to elements in elements that the greedy construction routine will include at the start of its construction.

  • seed (int) – Seed for the random number generator.

  • verbosity (int) – Sets the level of logging messages the printer will display.

Returns:

The best germ set from all locally-optimal germ sets constructed.

Return type:

list of Circuits

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