Package org.cicirello.search.operators.integers

Class IntegerValueInitializer

java.lang.Object

org.cicirello.search.operators.integers.IntegerValueInitializer

All Implemented Interfaces:

Splittable<Initializer<SingleInteger>>, Initializer<SingleInteger>

public class IntegerValueInitializer
extends Object
implements Initializer<SingleInteger>

Generates random SingleInteger 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 (SingleInteger) 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 SingleInteger.set(int) such that the SingleInteger.set(int) method will set the value to the min if a value is passed less than min (and similarly for max).

Constructor Summary

Constructors

Constructor	Description
IntegerValueInitializer(int a, int b)	Construct a IntegerValueInitializer that generates random solutions uniformly in the interval [a, b).
IntegerValueInitializer(int a, int b, int min, int max)	Construct a IntegerValueInitializer that generates random solutions uniformly in the interval [a, b), subject to bounds [min, max].

Method Summary

Modifier and Type	Method	Description
SingleInteger	createCandidateSolution()	Creates one candidate solution to a problem.
boolean	equals(Object other)
int	hashCode()
IntegerValueInitializer	split()	Generates a functionally identical copy of this object, for use in multithreaded implementations of search algorithms.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

IntegerValueInitializer

public IntegerValueInitializer(int a,
                               int b)

Construct a IntegerValueInitializer that generates random solutions uniformly in the interval [a, b). The SingleInteger 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

IntegerValueInitializer

public IntegerValueInitializer(int a,
                               int b,
                               int min,
                               int max)

Construct a IntegerValueInitializer 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 SingleInteger, 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

createCandidateSolution

public final SingleInteger createCandidateSolution()

Description copied from interface: Initializer

Creates one candidate solution to a problem.

Specified by:

createCandidateSolution in interface Initializer<SingleInteger>

Returns:

a candidate solution to a problem instance.

split

public IntegerValueInitializer 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<SingleInteger>>

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.

equals

public boolean equals(Object other)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object