Package org.optaplanner.core.impl.heuristic.selector.common.nearby

Class ParabolicDistributionNearbyRandom

java.lang.Object

org.optaplanner.core.impl.heuristic.selector.common.nearby.ParabolicDistributionNearbyRandom

All Implemented Interfaces:

NearbyRandom

public class ParabolicDistributionNearbyRandom
extends Object
implements NearbyRandom

P(x) = 3(m - x)²/m³.

Cumulative probability: F(x) = 1 - (1 - x/m)³.

Inverse cumulative probability: F(p) = m(1 - (1 - p)^(1/3)).

Field Summary

Fields

Modifier and Type	Field	Description
protected int	sizeMaximum

Constructor Summary

Constructors

Constructor	Description
ParabolicDistributionNearbyRandom(int sizeMaximum)

Method Summary

Modifier and Type	Method	Description
int	getOverallSizeMaximum()	Used to limit the RAM memory size of the nearby distance matrix.
int	nextInt(Random random, int nearbySize)

Methods inherited from class java.lang.Object

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

Field Detail

sizeMaximum

protected final int sizeMaximum

Constructor Detail

ParabolicDistributionNearbyRandom

public ParabolicDistributionNearbyRandom(int sizeMaximum)

Method Detail

nextInt

public int nextInt(Random random,
                   int nearbySize)

Specified by:

nextInt in interface NearbyRandom

Parameters:

random - never null

nearbySize - never negative. The number of available values to select from. Normally this is the size of the value range for a non-chained variable and the size of the value range (= size of the entity list) minus 1 for a chained variable.

Returns:

0 <= x < nearbySize

getOverallSizeMaximum

public int getOverallSizeMaximum()

Description copied from interface: NearbyRandom

Used to limit the RAM memory size of the nearby distance matrix.

Specified by:

getOverallSizeMaximum in interface NearbyRandom

Returns:

one more than the maximum number that NearbyRandom.nextInt(Random, int) can return, Integer.MAX_VALUE if there is none