
MOEA Framework 2.12 API Specification 

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java.lang.Object org.moeaframework.core.operator.real.SPX
public class SPX
Simplex crossover (SPX) operator. SPX is a multiparent operator, allowing a userdefined number of parents and offspring. The parents form a convex hull, called a simplex. Offspring are generated uniformly at random from within the simplex. The expansion rate parameter can be used to expand the size of the simplex beyond the bounds of the parents. For example, the figure below shows three parent points and the offspring distribution, clearly filling an expanded triangular simplex.
References:
Constructor Summary  

SPX(int numberOfParents,
int numberOfOffspring)
Constructs a SPX operator with the specified number of parents and number of offspring. 

SPX(int numberOfParents,
int numberOfOffspring,
double epsilon)
Constructs a simplex operator with the specified number of parents, number of offspring, and expansion rate. 
Method Summary  

Solution[] 
evolve(Solution[] parents)
Evolves one or more parent solutions (specified by getArity ) and
produces one or more child solutions. 
int 
getArity()
Returns the number of solutions that must be supplied to the evolve method. 
double 
getEpsilon()
Returns the expansion rate of this operator. 
int 
getNumberOfOffspring()
Returns the number of offspring produced by this operator. 
int 
getNumberOfParents()
Returns the number of parents required by this operator. 
Methods inherited from class java.lang.Object 

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

public SPX(int numberOfParents, int numberOfOffspring)
sqrt(numberOfParents+1)
to preserve the covariance matrix of the
population.
numberOfParents
 the number of parentsnumberOfOffspring
 the number of offspringpublic SPX(int numberOfParents, int numberOfOffspring, double epsilon)
numberOfParents
 the number of parentsnumberOfOffspring
 the number of offspringepsilon
 the expansion rateMethod Detail 

public Solution[] evolve(Solution[] parents)
Variation
getArity
) and
produces one or more child solutions. By contract, the parents must not
be modified. The copy constructor should be used to create copies of the
parents with these copies subsequently modified.
evolve
in interface Variation
parents
 the array of parent solutions
public int getArity()
Variation
evolve
method.
getArity
in interface Variation
evolve
methodpublic int getNumberOfParents()
public int getNumberOfOffspring()
public double getEpsilon()

MOEA Framework 2.12 API Specification 

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