Class UniformMutation<T extends IntegerValued>
- java.lang.Object
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- org.cicirello.search.operators.integers.UniformMutation<T>
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- Type Parameters:
T
- The specific IntegerValued type.
- All Implemented Interfaces:
Splittable<MutationOperator<T>>
,MutationOperator<T>
,IntegerValued
,Copyable<UniformMutation<T>>
- Direct Known Subclasses:
UndoableUniformMutation
public class UniformMutation<T extends IntegerValued> extends Object implements MutationOperator<T>, IntegerValued, Copyable<UniformMutation<T>>
This class implements a uniform mutation for mutating integer values. This class can be used to mutate objects of any of the classes that implement the
IntegerValued
interface, including both univariates and multivariates.In the form of uniform mutation implemented by this class, a value v is mutated by adding to it a randomly generated integer m such that m is drawn uniformly at random from the interval [-radius, radius].
This mutation operator also implements the
IntegerValued
interface to enable implementation of metaheuristics that mutate their own mutation parameters. That is, you can pass a UniformMutation object to themutate(T)
method of a UniformMutation object to mutate its radius.To construct a UniformMutation, you must use one of the factory methods. See the various
createUniformMutation(int)
methods.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description UniformMutation<T>
copy()
Creates an identical copy of this object.static <T extends IntegerValued>
UniformMutation<T>createUniformMutation(int radius)
Creates a Uniform mutation operator.static <T extends IntegerValued>
UniformMutation<T>createUniformMutation(int radius, double p)
Create a Uniform mutation operator.static <T extends IntegerValued>
UniformMutation<T>createUniformMutation(int radius, int k)
Create a Uniform mutation operator.boolean
equals(Object other)
Indicates whether some other object is equal to this one.int
get(int i)
Accesses the current value of radius.int
hashCode()
Returns a hash code value for the object.int
length()
Gets the number of parameters.void
mutate(T c)
Mutates a candidate solution to a problem, by randomly modifying its state.void
set(int i, int value)
Sets radius to a specified value.UniformMutation<T>
split()
Generates a functionally identical copy of this object, for use in multithreaded implementations of search algorithms.int[]
toArray(int[] values)
Accesses the current value of radius as an array.
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Method Detail
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createUniformMutation
public static <T extends IntegerValued> UniformMutation<T> createUniformMutation(int radius)
Creates a Uniform mutation operator.- Type Parameters:
T
- The specific IntegerValued type.- Parameters:
radius
- The radius parameter of the Uniform.- Returns:
- A Uniform mutation operator.
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createUniformMutation
public static <T extends IntegerValued> UniformMutation<T> createUniformMutation(int radius, int k)
Create a Uniform mutation operator.- Type Parameters:
T
- The specific IntegerValued type.- Parameters:
radius
- The radius parameter of the Uniform mutation.k
- The number of input variables that themutate(T)
method changes when called. The k input variables are chosen uniformly at random from among all subsets of size k. If there are less than k input variables, then all are mutated.- Returns:
- A Uniform mutation operator
- Throws:
IllegalArgumentException
- if k < 1
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createUniformMutation
public static <T extends IntegerValued> UniformMutation<T> createUniformMutation(int radius, double p)
Create a Uniform mutation operator.- Type Parameters:
T
- The specific IntegerValued type.- Parameters:
radius
- The radius parameter of the Uniform mutation.p
- The probability that themutate(T)
method changes an input variable. If there are n input variables, then n*p input variables will be mutated on average during a single call to themutate(T)
method. A value of p > 1 is treated as p = 1.- Returns:
- A Uniform mutation operator
- Throws:
IllegalArgumentException
- if p ≤ 0
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mutate
public void mutate(T c)
Description copied from interface:MutationOperator
Mutates a candidate solution to a problem, by randomly modifying its state. The mutant that is produced is in the local neighborhood of the original candidate solution.- Specified by:
mutate
in interfaceMutationOperator<T extends IntegerValued>
- Parameters:
c
- The candidate solution subject to the mutation. This method changes the state of c.
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split
public UniformMutation<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 extends IntegerValued>
- 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.
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copy
public UniformMutation<T> copy()
Creates an identical copy of this object.- Specified by:
copy
in interfaceCopyable<T extends IntegerValued>
- Returns:
- an identical copy of this object
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equals
public boolean equals(Object other)
Indicates whether some other object is equal to this one. The objects are equal if they are the same type of operator with the same parameters.
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hashCode
public int hashCode()
Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by HashMap.
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length
public final int length()
Description copied from interface:IntegerValued
Gets the number of parameters.- Specified by:
length
in interfaceIntegerValued
- Returns:
- The number of parameters for this function.
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get
public final int get(int i)
Accesses the current value of radius.- Specified by:
get
in interfaceIntegerValued
- Parameters:
i
- Ignored.- Returns:
- The current value of radius.
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toArray
public final int[] toArray(int[] values)
Accesses the current value of radius as an array. This method implemented strictly to meet implementation requirements of IntegerValued interface.- Specified by:
toArray
in interfaceIntegerValued
- Parameters:
values
- An array to hold the result. If values is null or if values.length is not equal 1, then a new array is constructed for the result.- Returns:
- An array containing the current value of radius.
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set
public final void set(int i, int value)
Sets radius to a specified value.- Specified by:
set
in interfaceIntegerValued
- Parameters:
i
- Ignored.value
- The new value for radius.
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