org.uma.jmetal.util

Class SolutionListUtils

java.lang.Object

org.uma.jmetal.util.SolutionListUtils

public class SolutionListUtils
extends Object

Created by Antonio J. Nebro on 04/10/14. Modified by Juanjo 13/03/15

Constructor Summary

Constructors

Constructor and Description
SolutionListUtils()

Method Summary

Modifier and Type	Method and Description
static <S extends Solution<?>> double[][]	distanceMatrix(List<S> solutionSet) Returns a matrix with the euclidean distance between each pair of solutions in the population.
static <S extends Solution<?>> void	fillPopulationWithNewSolutions(List<S> solutionList, Problem<S> problem, int maxListSize) Fills a population with new solutions until its size is maxListSize
static <S extends Solution<?>> S	findBestSolution(List<S> solutionList, Comparator<S> comparator)
static <S extends Solution<?>> int	findIndexOfBestSolution(List<S> solutionList, Comparator<S> comparator) Finds the index of the best solution in the list according to a comparator
static int	findIndexOfWorstSolution(List<? extends Solution<?>> solutionList, Comparator<Solution<?>> comparator) Finds the index of the worst solution in the list according to a comparator
<S extends Solution<?>> S	findWorstSolution(Collection<S> solutionList, Comparator<S> comparator)
static <S extends Solution<?>> List<S>	getInvertedFront(List<S> solutionSet) This method receives a normalized list of non-dominated solutions and return the inverted one.
static <S extends Solution<?>> List<S>	getNondominatedSolutions(List<S> solutionList)
static List<Solution<?>>	getNormalizedFront(List<Solution<?>> solutionList, List<Double> maximumValue, List<Double> minimumValue) This method receives a list of non-dominated solutions and maximum and minimum values of the objectives, and returns a the normalized set of solutions.
static <S extends Solution<?>> boolean	isSolutionDominatedBySolutionList(S solution, List<? extends S> solutionSet)
static <S extends Solution<?>> void	removeSolutionsFromList(List<S> solutionList, int numberOfSolutionsToRemove) Removes a number of solutions from a list
static <S extends Solution<?>> void	restart(List<S> solutionList, Problem<S> problem, int percentageOfSolutionsToRemove) This methods takes a list of solutions, removes a percentage of its solutions, and it is filled with new random generated solutions
static <S extends Solution<?>> List<S>	selectNRandomDifferentSolutions(int numberOfSolutionsToBeReturned, List<S> solutionList) This method receives a normalized list of non-dominated solutions and return the inverted one.
static <S extends Solution<?>> boolean	solutionListsAreEquals(List<S> solutionList, List<S> newSolutionList) Compares two solution lists to determine if both are equals
static <S extends Solution<?>> double[][]	writeObjectivesToMatrix(List<S> solutionList)

Methods inherited from class java.lang.Object

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

Constructor Detail

SolutionListUtils

public SolutionListUtils()

Method Detail

getNondominatedSolutions

public static <S extends Solution<?>> List<S> getNondominatedSolutions(List<S> solutionList)

findWorstSolution

public <S extends Solution<?>> S findWorstSolution(Collection<S> solutionList,
                                                   Comparator<S> comparator)

findIndexOfBestSolution

public static <S extends Solution<?>> int findIndexOfBestSolution(List<S> solutionList,
                                                                  Comparator<S> comparator)

Finds the index of the best solution in the list according to a comparator

Parameters:

solutionList -

comparator -

Returns:

The index of the best solution

findIndexOfWorstSolution

public static int findIndexOfWorstSolution(List<? extends Solution<?>> solutionList,
                                           Comparator<Solution<?>> comparator)

Finds the index of the worst solution in the list according to a comparator

Parameters:

solutionList -

comparator -

Returns:

The index of the best solution

findBestSolution

public static <S extends Solution<?>> S findBestSolution(List<S> solutionList,
                                                         Comparator<S> comparator)

writeObjectivesToMatrix

public static <S extends Solution<?>> double[][] writeObjectivesToMatrix(List<S> solutionList)

getNormalizedFront

public static List<Solution<?>> getNormalizedFront(List<Solution<?>> solutionList,
                                                   List<Double> maximumValue,
                                                   List<Double> minimumValue)

This method receives a list of non-dominated solutions and maximum and minimum values of the objectives, and returns a the normalized set of solutions.

Parameters:

solutionList - A list of non-dominated solutions

maximumValue - The maximum values of the objectives

minimumValue - The minimum values of the objectives

Returns:

the normalized list of non-dominated solutions

getInvertedFront

public static <S extends Solution<?>> List<S> getInvertedFront(List<S> solutionSet)

This method receives a normalized list of non-dominated solutions and return the inverted one. This operation is needed for minimization problem

Parameters:

solutionSet - The front to invert

Returns:

The inverted front

isSolutionDominatedBySolutionList

public static <S extends Solution<?>> boolean isSolutionDominatedBySolutionList(S solution,
                                                                                List<? extends S> solutionSet)

selectNRandomDifferentSolutions

public static <S extends Solution<?>> List<S> selectNRandomDifferentSolutions(int numberOfSolutionsToBeReturned,
                                                                              List<S> solutionList)

This method receives a normalized list of non-dominated solutions and return the inverted one. This operation is needed for minimization problem

Parameters:

solutionList - The front to invert

Returns:

The inverted front

distanceMatrix

public static <S extends Solution<?>> double[][] distanceMatrix(List<S> solutionSet)

Returns a matrix with the euclidean distance between each pair of solutions in the population. Distances are measured in the objective space

Parameters:

solutionSet -

Returns:

solutionListsAreEquals

public static <S extends Solution<?>> boolean solutionListsAreEquals(List<S> solutionList,
                                                                     List<S> newSolutionList)

Compares two solution lists to determine if both are equals

Parameters:

solutionList - A Solution list

newSolutionList - A Solution list

Returns:

true if both are contains the same solutions, false in other case

restart

public static <S extends Solution<?>> void restart(List<S> solutionList,
                                                   Problem<S> problem,
                                                   int percentageOfSolutionsToRemove)

This methods takes a list of solutions, removes a percentage of its solutions, and it is filled with new random generated solutions

Parameters:

solutionList -

problem -

percentageOfSolutionsToRemove -

removeSolutionsFromList

public static <S extends Solution<?>> void removeSolutionsFromList(List<S> solutionList,
                                                                   int numberOfSolutionsToRemove)

Removes a number of solutions from a list

Parameters:

solutionList - The list of solutions

numberOfSolutionsToRemove -

fillPopulationWithNewSolutions

public static <S extends Solution<?>> void fillPopulationWithNewSolutions(List<S> solutionList,
                                                                          Problem<S> problem,
                                                                          int maxListSize)

Fills a population with new solutions until its size is maxListSize

Type Parameters:

S - The type of the solutions to be created

Parameters:

solutionList - The list of solutions

problem - The problem being solved

maxListSize - The target size of the list