Module org.cicirello.chips_n_salsa
Class WindowLimitedUndoableScrambleMutation
java.lang.Object
org.cicirello.search.operators.permutations.UndoableScrambleMutation
org.cicirello.search.operators.permutations.WindowLimitedUndoableScrambleMutation
- All Implemented Interfaces:
PermutationUnaryOperator
,Splittable<MutationOperator<Permutation>>
,MutationOperator<Permutation>
,UndoableMutationOperator<Permutation>
This class implements a window-limited version of the
ScrambleMutation
mutation operator
on permutations. A window-limited mutation operator on permutations is a mutation operator such
that there is a window constraint, w, on the random indexes used by the mutation. For a mutation
operator that uses a pair of random indexes, (i, j), these indexes are constrained such that
|i-j| ≤ w. All index pairs that satisfy the window constraint are equally likely.
The runtime (worst case and average case) of both the mutate
and
undo
methods is O(min(n,w)), where n is the length of the permutation.
Since chosen indexes can be no more than w positions apart, at most (w+1) elements are moved.
For further discussion of window limited permutation mutation operators see:
V. A. Cicirello, "On the Effects of Window-Limits on the Distance Profiles of Permutation Neighborhood
Operators," in Proceedings of the 8th International Conference on Bioinspired Information and
Communications Technologies, pages 28–35, December 2014.
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Constructor Summary
ConstructorsConstructorDescriptionConstructs a WindowLimitedUndoableScrambleMutation mutation operator with a default window limit of Integer.MAX_VALUE.WindowLimitedUndoableScrambleMutation
(int windowLimit) Constructs a WindowLimitedUndoableScrambleMutation mutation operator with the undo method enabled. -
Method Summary
Modifier and TypeMethodDescriptionsplit()
Generates a functionally identical copy of this object, for use in multithreaded implementations of search algorithms.Methods inherited from class org.cicirello.search.operators.permutations.UndoableScrambleMutation
apply, mutate, undo
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Constructor Details
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WindowLimitedUndoableScrambleMutation
public WindowLimitedUndoableScrambleMutation()Constructs a WindowLimitedUndoableScrambleMutation mutation operator with a default window limit of Integer.MAX_VALUE. -
WindowLimitedUndoableScrambleMutation
public WindowLimitedUndoableScrambleMutation(int windowLimit) Constructs a WindowLimitedUndoableScrambleMutation mutation operator with the undo method enabled.- Parameters:
windowLimit
- The window limit, which must be positive.- Throws:
IllegalArgumentException
- if windowLimit ≤ 0
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Method Details
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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<MutationOperator<Permutation>>
- Specified by:
split
in interfaceUndoableMutationOperator<Permutation>
- Overrides:
split
in classUndoableScrambleMutation
- 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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