public final class PartiallyMatchedCrossover<T,C extends Comparable<? super C>> extends Crossover<EnumGene<T>,C>
PartiallyMatchedCrossover
(PMX) guarantees that all Gene
s
are found exactly once in each chromosome. No gene is duplicated by this
crossover. The PMX can be applied usefully in the TSP or other permutation
problem encodings. Permutation encoding is useful for all problems where the
fitness only depends on the ordering of the genes within the chromosome. This
is the case in many combinatorial optimization problems. Other crossover
operators for combinatorial optimization are:
The PMX is similar to the two-point crossover. A crossing region is chosen by selecting two crossing points.
C1 = 012|345|6789 C2 = 987|654|3210After performing the crossover we normally got two invalid chromosomes.
C1 = 012|654|6789 C2 = 987|345|3210Chromosome
C1
contains the value 6 twice and misses the value
3. On the other side chromosome C2
contains the value 3 twice and
misses the value 6. We can observe that this crossover is equivalent
to the exchange of the values 3 -> 6
, 4 -> 5
and
5 -> 4
. To repair the two
chromosomes we have to apply this exchange outside the crossing region.
C1 = 012|654|3789 C2 = 987|345|6210The
PartiallyMatchedCrossover
class requires chromosomes with the
same length. An IllegalArgumentException
is thrown at runtime if this
requirement is not fulfilled.PermutationChromosome
_probability
DEFAULT_ALTER_PROBABILITY
Constructor and Description |
---|
PartiallyMatchedCrossover(double probability) |
Modifier and Type | Method and Description |
---|---|
protected int |
crossover(MSeq<EnumGene<T>> that,
MSeq<EnumGene<T>> other)
Template method which performs the crossover.
|
String |
toString() |
alter, getOrder
equals, getProbability, hashCode
public PartiallyMatchedCrossover(double probability)
© 2007-2018 Franz Wilhelmstötter (2018-10-28 17:23)