- All Implemented Interfaces:
public final class BitFlipMutation extends Object implements UndoableMutationOperator<BitVector>
This class implements Bit Flip Mutation, the mutation operator commonly used in genetic algorithms, but which can also be used with other metaheuristic search algorithms such as simulated annealing to generate random neighbors.
In a bit flip mutation, each bit of the BitVector is flipped with probability M, known as the mutation rate. Flipping a bit means changing it to 0 if it is currently a 1, or changing it to 1 if it is currently a 0. If the length of the BitVector is N, then the expected number of bits flipped during a single call to the
mutate(org.cicirello.search.representations.BitVector)method is NM. However, there is no guarantee that any bits will be flipped by a call to the
mutate(org.cicirello.search.representations.BitVector)method. This behavior is fine for genetic algorithms, but may be less than desirable for other metaheuristics, such as those that operate on a single candidate solution rather than a population of them. If you have need for a mutation operator for BitVectors that guarantees that all calls to the
mutate(org.cicirello.search.representations.BitVector)method will change the BitVector, then consider using the
Constructors Constructor Description
BitFlipMutation(double m)Constructs a BitFlipMutation operator with a specified mutation rate.
All Methods Instance Methods Concrete Methods Modifier and Type Method Description
mutate(BitVector c)Mutates a candidate solution to a problem, by randomly modifying its state.
undo(BitVector c)Returns a candidate solution to its previous state prior to the most recent mutation performed.
public BitFlipMutation(double m)Constructs a BitFlipMutation operator with a specified mutation rate.
m- The mutation rate, which is the probability of flipping any individual bit. The expected number of bits flipped during a call to the
mutate(org.cicirello.search.representations.BitVector)method is m*N where N is the length of the mutated BitVector. There is no guarantee that any bits will be flipped during a mutation (e.g., if m is close to 0).
IllegalArgumentException- if m ≤ 0 or if m ≥ 1.
public void mutate(BitVector c)Description copied from interface:
public void undo(BitVector c)Description copied from interface:
Returns a candidate solution to its previous state prior to the most recent mutation performed.
public BitFlipMutation split()Description copied from interface:
Copyableinterface. 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:
- Specified by:
- 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.