Module org.cicirello.chips_n_salsa
Package org.cicirello.search.operators
Class WeightedHybridCrossover<T>
 java.lang.Object

 org.cicirello.search.operators.WeightedHybridCrossover<T>

 Type Parameters:
T
 The type of object used to represent candidate solutions to the problem.
 All Implemented Interfaces:
Splittable<CrossoverOperator<T>>
,CrossoverOperator<T>
public final class WeightedHybridCrossover<T> extends Object implements CrossoverOperator<T>
A WeightedHybridCrossover enables using multiple crossover operators, such that each time the
cross(T, T)
method is called, a randomly chosen crossover operator is applied to the candidate solutions. The random choice of crossover operator is weighted proportionately based on an array of weights passed upon construction.Consider the following weights: w = [ 1, 2, 3]. In this example, the first crossover operator will be used with probability 0.167, the second crossover operator will be used with probability 2/6 = 0.333, and the third crossover operator will be used with probability 3/6 = 0.5.


Constructor Summary
Constructors Constructor Description WeightedHybridCrossover(Collection<? extends CrossoverOperator<T>> ops, int[] weights)
Constructs a WeightedHybridCrossover from a Collection of CrossoverOperators.

Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
cross(T c1, T c2)
Performs a crossover for an evolutionary algorithm, such that crossover forms two children from two parents.WeightedHybridCrossover<T>
split()
Generates a functionally identical copy of this object, for use in multithreaded implementations of search algorithms.



Constructor Detail

WeightedHybridCrossover
public WeightedHybridCrossover(Collection<? extends CrossoverOperator<T>> ops, int[] weights)
Constructs a WeightedHybridCrossover from a Collection of CrossoverOperators. Parameters:
ops
 A Collection of CrossoverOperators.weights
 The array of weights, whose length must be equal to ops.size(). Every element of weights must be greater than 0. Throws:
IllegalArgumentException
 if ops doesn't contain any CrossoverOperators.IllegalArgumentException
 if ops.size() is not equal to weights.length.IllegalArgumentException
 if any weights are nonpositive.


Method Detail

cross
public void cross(T c1, T c2)
Description copied from interface:CrossoverOperator
Performs a crossover for an evolutionary algorithm, such that crossover forms two children from two parents. Implementations of this method modify the parameters, transforming the parents into the children. Specified by:
cross
in interfaceCrossoverOperator<T>
 Parameters:
c1
 A candidate solution subject to the crossover. This method changes the state of c1.c2
 A candidate solution subject to the crossover. This method changes the state of c2.

split
public WeightedHybridCrossover<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 theCopyable
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 interfaceSplittable<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.

