org.moeaframework.core
Class FastNondominatedSorting

java.lang.Object
  org.moeaframework.core.FastNondominatedSorting

public class FastNondominatedSorting
extends Object

Fast non-dominated sorting algorithm for dominance depth ranking. Assigns the rank and crowdingDistance attributes to solutions. Solutions of rank 0 belong to the Pareto non-dominated front.

References:

1. Deb et al (2002). "A Fast and Elitist Multiobjective Genetic Algorithm: NSGA-II." IEEE Transactions on Evolutionary Computation. 6(2):182-197.

Field Summary

static String	CROWDING_ATTRIBUTE Attribute key for the crowding distance of a solution.
static String	RANK_ATTRIBUTE Attribute key for the rank of a solution.

Constructor Summary

FastNondominatedSorting()
Constructs a fast non-dominated sorting operator using Pareto dominance.

FastNondominatedSorting(DominanceComparator comparator)
Constructs a fast non-dominated sorting operator using the specified dominance comparator.

Method Summary

void	evaluate(Population population) Performs fast non-dominated sorting on the specified population, assigning the rank and crowdingDistance attributes to solutions.
DominanceComparator	getComparator() Returns the dominance comparator used by this fast non-dominated sorting routine.
void	updateCrowdingDistance(Population front) Computes and assigns the crowdingDistance attribute to solutions.

Methods inherited from class java.lang.Object

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

Field Detail

RANK_ATTRIBUTE

public static final String RANK_ATTRIBUTE

Attribute key for the rank of a solution.

See Also:

Constant Field Values

CROWDING_ATTRIBUTE

public static final String CROWDING_ATTRIBUTE

Attribute key for the crowding distance of a solution.

See Also:

Constant Field Values

Constructor Detail

FastNondominatedSorting

public FastNondominatedSorting()

Constructs a fast non-dominated sorting operator using Pareto dominance.

FastNondominatedSorting

public FastNondominatedSorting(DominanceComparator comparator)

Constructs a fast non-dominated sorting operator using the specified dominance comparator.

Parameters:

comparator - the dominance comparator

Method Detail

getComparator

public DominanceComparator getComparator()

Returns the dominance comparator used by this fast non-dominated sorting routine.

Returns:

the dominance comparator used by this fast non-dominated sorting routine

evaluate

public void evaluate(Population population)

Performs fast non-dominated sorting on the specified population, assigning the rank and crowdingDistance attributes to solutions.

Parameters:

population - the population whose solutions are to be evaluated

updateCrowdingDistance

public void updateCrowdingDistance(Population front)

Computes and assigns the crowdingDistance attribute to solutions. The specified population should consist of solutions within the same front/rank.

Parameters:

front - the population whose solutions are to be evaluated