Package org.cicirello.search.operators.reals

Class RealValueInitializer

  • All Implemented Interfaces:
    Splittable<Initializer<SingleReal>>, Initializer<SingleReal>
    public class RealValueInitializer
extends Object
implements Initializer<SingleReal>
    Generating random SingleReal objects for use in generating random initial solutions for simulated annealing and other metaheuristics, and for copying such objects. This initializer supports both unbounded objects (SingleReal) as well as bounded reals, where the domain of values is bound in an interval. In the bounded case, the objects created by this class enforce the bounds upon calls to SingleReal.set(double) such that the SingleReal.set(double) method will set the value to the min if a value is passed less than min (and similarly for max).

    • Constructor Detail

      • RealValueInitializer

        public RealValueInitializer​(double a,
                            double b)
        Construct a RealValueInitializer that generates random solutions uniformly in the interval [a, b). The SingleReal objects returned by the createCandidateSolution() method are otherwise unbounded (i.e., future mutations may alter the value such that it leaves that interval). Use the other constructor if you need to enforce bounds.
        Parameters:
        a - The lower end of the interval (inclusive).
        b - The upper end of the interval (exclusive).
        Throws:
        IllegalArgumentException - if a ≥ b

      • RealValueInitializer

        public RealValueInitializer​(double a,
                            double b,
                            double min,
                            double max)
        Construct a RealValueInitializer that generates random solutions uniformly in the interval [a, b), subject to bounds [min, max]. If this constructor is used, then the createCandidateSolution() method will return an object of a subclass of SingleReal, which will enforce the constraint that the value of the function inputs must remain in the interval [min, max] as mutation and other operators are applied.
        Parameters:
        a - The lower end of the interval (inclusive).
        b - The upper end of the interval (exclusive).
        min - Lower bound on allowed values for the function inputs generated.
        max - Upper bound on allowed values for the function inputs generated.
        Throws:
        IllegalArgumentException - if a ≥ b

    • Method Detail

      • split

        public RealValueInitializer 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<SingleReal>>
        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.

      • hashCode

        public int hashCode()
        Overrides:
        hashCode in class Object