Module org.cicirello.chips_n_salsa
Package org.cicirello.search

Interface SimpleMetaheuristic<T extends Copyable<T>>

Type Parameters:
T - The type of object under optimization.
All Superinterfaces:
Splittable<TrackableSearch<T>>, TrackableSearch<T>
All Known Subinterfaces:
SimpleLocalMetaheuristic<T>
All Known Implementing Classes:
AcceptanceBandSampling, FirstDescentHillClimber, HeuristicBiasedStochasticSampling, HeuristicPermutationGenerator, HeuristicSolutionGenerator, IterativeSampling, SteepestDescentHillClimber, ValueBiasedStochasticSampling
public interface SimpleMetaheuristic<T extends Copyable<T>> extends TrackableSearch<T>
This interface defines the required methods for implementations of simple metaheuristics whose run length is self-determined, such as hill climbers that terminate upon reaching a local optima.

  • Method Summary

    Modifier and Type
    Method
    Description
    SolutionCostPair<T>
    optimize()
    Executes a single run of a metaheuristic whose run length cannot be specified (e.g., a hill climber that terminates when it reaches a local optima, or a stochastic sampler that terminates when it constructs one solution, etc).
    SimpleMetaheuristic<T>
    split()
    Generates a functionally identical copy of this object, for use in multithreaded implementations of search algorithms.

    Methods inherited from interface org.cicirello.search.TrackableSearch

    getProblem, getProgressTracker, getTotalRunLength, setProgressTracker

  • Method Details

    • optimize

      SolutionCostPair<T> optimize()
      Executes a single run of a metaheuristic whose run length cannot be specified (e.g., a hill climber that terminates when it reaches a local optima, or a stochastic sampler that terminates when it constructs one solution, etc). If this method is called multiple times, each call is randomized in some algorithm dependent way (e.g., a hill climber begins at a new randomly generated starting solution), and reinitializes any control parameters that may have changed during the previous call to optimize to the start of run state.
      Returns:
      The current solution at the end of this run and its cost, which may or may not be the same as the solution contained in this metaheuristic's ProgressTracker, which contains the best of all runs. Returns null if the run did not execute, such as if the ProgressTracker already contains the theoretical best solution.

    • split

      SimpleMetaheuristic<T> split()
      Description copied from interface: Splittable
      Generates a functionally identical copy of this object, for use in multithreaded implementations of search algorithms. The state of the object that is returned may or may not be identical to that of the original. Thus, this is a distinct concept from the functionality of the Copyable interface. Classes that implement this interface must ensure that the object returned performs the same functionality, and that it does not share any state data that would be either unsafe or inefficient for concurrent access by multiple threads. The split method is allowed to simply return the this reference, provided that it is both safe and efficient for multiple threads to share a single copy of the Splittable object. The intention is to provide a multithreaded search with the capability to provide spawned threads with their own distinct search operators. Such multithreaded algorithms can call the split method for each thread it spawns to generate a functionally identical copy of the operator, but with independent state.
      Specified by:
      split in interface Splittable<T extends Copyable<T>>
      Returns:
      A functionally identical copy of the object, or a reference to this if it is both safe and efficient for multiple threads to share a single instance of this Splittable object.