jenes.tutorials.problem3

Class TSPCityCenteredCrossover

java.lang.Object

jenes.stage.AbstractStage<T>

jenes.stage.operator.Operator<T>

jenes.stage.operator.Crossover<IntegerChromosome>

jenes.tutorials.problem3.TSPCityCenteredCrossover

public class TSPCityCenteredCrossover
extends Crossover<IntegerChromosome>

Tutorial showing how to implement problem specific operators. The problem faced in this example is the well known Tavel Salesman Problem (TSP) This class implements a specific crossover aimed at preserving permutations. Algorithm description:

      parent1  5 2 1 4 6 3     parent2   1 3 2 4 6 5
      child1   _ _ _ _ _ _     child2    _ _ _ _ _ _

Step 1: a city is choosed randomly. We copy all the cities until the selected one from each parent to each child (parent1 in child1 and parent2 in child2)

      parent1  5 2 1 4 6 3     parent2   1 3 2 4 6 5
      child1   5 2 _ _ _ _     child2    1 3 2 _ _ _
 

Step 2: we fill child1 getting missing elements from parent2; these ones will have the same parent2 order

      parent1  5 2 1 4 6 3     parent2  1 3 2 4 6 5
      child1   5 2 1 3 4 6     child2   1 3 2 5 4 6

We repeat these steps for child2

Since:

1.0

Version:

2.0

Nested Class Summary

Nested classes/interfaces inherited from class jenes.stage.operator.Crossover

Crossover.Statistics

Field Summary

Fields inherited from class jenes.stage.operator.Crossover

probability

Fields inherited from class jenes.stage.operator.Operator

random, statistics

Fields inherited from class jenes.stage.AbstractStage

biggerIsBetter, fitness, ga

Constructor Summary

Constructors

Constructor and Description
TSPCityCenteredCrossover(double pCross)

Method Summary

Methods

Modifier and Type	Method and Description
protected void	cross(Individual<IntegerChromosome>[] offsprings) This method implements the crossover operation.
int	spread() Returns the number of chromosomes (i.e. 2) this operator entails.

Methods inherited from class jenes.stage.operator.Crossover

getProbability, init, process, setProbability

Methods inherited from class jenes.stage.operator.Operator

getStatistics, updateStatistics

Methods inherited from class jenes.stage.AbstractStage

dispose, getFitness, isBiggerBetter, isFitnessChanged, setBiggerIsBetter, setBiggerIsBetter, setFitness, setFitness

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TSPCityCenteredCrossover

public TSPCityCenteredCrossover(double pCross)

Method Detail

spread

public int spread()

Returns the number of chromosomes (i.e. 2) this operator entails.

Specified by:

spread in class Crossover<IntegerChromosome>

Returns:

the number of individuals required by crossover

cross

protected void cross(Individual<IntegerChromosome>[] offsprings)

This method implements the crossover operation.

Specified by:

cross in class Crossover<IntegerChromosome>

Parameters:

offsprings - the chromosomes to be crossed.