Package org.moeaframework.algorithm.single

Class MinMaxObjectiveComparator

java.lang.Object

org.moeaframework.algorithm.single.MinMaxObjectiveComparator

All Implemented Interfaces:

Comparator<Solution>, AggregateObjectiveComparator, DominanceComparator

public class MinMaxObjectiveComparator
extends Object
implements AggregateObjectiveComparator

Weighted min-max aggregate function. By default, all weights are assumed to be equal.

See Also:

• MinMaxDominanceComparator

Constructor Summary

Constructors

Constructor	Description
MinMaxObjectiveComparator(double... weights)	Constructs a new comparator using a weighted min-max aggregate function.

Method Summary

Modifier and Type	Method	Description
double	calculateFitness(Solution solution)	Calculates the aggregate (fitness) value of the solution using this aggregate function.
static double	calculateFitness(Solution solution, double[] weights)	Computes the weighted min-max aggregate fitness of the solution.
int	compare(Solution solution1, Solution solution2)	Compares the two solutions using a dominance relation, returning -1 if solution1 dominates solution2, 1 if solution2 dominates solution1, and 0 if the solutions are non-dominated.
double[]	getWeights()	Returns the weights used by this aggregate function.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Comparator

equals, reversed, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

Constructor Details

MinMaxObjectiveComparator

public MinMaxObjectiveComparator(double... weights)

Constructs a new comparator using a weighted min-max aggregate function. One weight should be given for each objective; if fewer weights are provided, the last weight is repeated for the remaining objectives. Defaults to weights of 1.0 if none are provided.

Parameters:

weights - the weight vector

Method Details

getWeights

public double[] getWeights()

Description copied from interface: AggregateObjectiveComparator

Returns the weights used by this aggregate function.

Specified by:

getWeights in interface AggregateObjectiveComparator

Returns:

the weights

compare

public int compare(Solution solution1,
 Solution solution2)

Description copied from interface: DominanceComparator

Compares the two solutions using a dominance relation, returning -1 if solution1 dominates solution2, 1 if solution2 dominates solution1, and 0 if the solutions are non-dominated.

Specified by:

compare in interface Comparator<Solution>

Specified by:

compare in interface DominanceComparator

Parameters:

solution1 - the first solution

solution2 - the second solution

Returns:

-1 if solution1 dominates solution2, 1 if solution2 dominates solution1, and 0 if the solutions are non-dominated

calculateFitness

public double calculateFitness(Solution solution)

Description copied from interface: AggregateObjectiveComparator

Calculates the aggregate (fitness) value of the solution using this aggregate function.

Specified by:

calculateFitness in interface AggregateObjectiveComparator

Parameters:

solution - the solution

Returns:

the aggregate value (smaller is better)

calculateFitness

public static double calculateFitness(Solution solution,
 double[] weights)

Computes the weighted min-max aggregate fitness of the solution. One weight should be given for each objective; if fewer weights are provided, the last weight is repeated for the remaining objectives.

Parameters:

solution - the solution

weights - the weight vector

Returns:

the fitness, where smaller values are preferred