Package org.cicirello.search.operators.permutations

Class PermutationInitializer

  • All Implemented Interfaces:
    Splittable<Initializer<Permutation>>, Initializer<Permutation>
    public final class PermutationInitializer
extends Object
implements Initializer<Permutation>

    The PermutationInitializer provides metaheuristic implementations, such as of simulated annealing, etc, with a way to generate random initial solutions to a problem, as well as a way to make copies of current solution configurations. Since it implements the Initializer interface, which relies on generics, such implementations of search algorithms such as simulated annealing, etc, do not need to know the representation of solutions.

    This initializer generates permutations uniformly at random from among the space of permutations. This is the typical case for many metaheuristics (e.g., hill climbers and simulated annealers often begin at a random solution).

    • Constructor Detail

      • PermutationInitializer

        public PermutationInitializer​(int n)
        Constructs a PermutationInitializer.
        Parameters:
        n - The length of the permutations generated by this permutation initializer. n must be non-negative.
        Throws:
        IllegalArgumentException - if n is negative.

    • Method Detail

      • split

        public PermutationInitializer 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<Initializer<Permutation>>
        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.