messif.buckets.split.impl
Class SplitPolicyMultiWayBallPartitioning

java.lang.Object
  messif.buckets.split.SplitPolicy
      messif.buckets.split.impl.SplitPolicyMultiWayBallPartitioning

All Implemented Interfaces:

ObjectMatcher<LocalAbstractObject>

public class SplitPolicyMultiWayBallPartitioning
extends SplitPolicy

This class is a multi-way ball-partitioning policy for bucket splitting.

The policy is fully defined by:
LocalAbstractObject pivot
float[] list of radii

The number of partitions produced by this policy is defined by the length of radii array incremented by one.

The values of radii define the boundaries between two partitiongs. So, the first partition will contain objects within this range of distances from pivot: [0,radii[0]]. The second partition will contain objects within this range of distances from pivot: (radii[0],radii[1]]. Finally, the last partition will contain objects within this range of distances from pivot: (radii[last],infinity). The matcher returns the index of the corresponding partition starting from zero.

Nested Class Summary

Nested classes/interfaces inherited from class messif.buckets.split.SplitPolicy

SplitPolicy.ParameterField

Field Summary

protected float	dist The distance to the pivot computed by the last call to match(Region).
protected LocalAbstractObject	pivot Policy parameter pivot
protected float[]	radii Policy parameter radius

Fields inherited from class messif.buckets.split.SplitPolicy

PART_ID_ANY

Constructor Summary

SplitPolicyMultiWayBallPartitioning()
Creates a new instance of SplitPolicyBallPartitioning

Method Summary

float	getDistanceToPivot() Returns the distance to the pivot which might have been computed by the last call to match(Region).
int	getPartitionsCount() Returns the number of partitions of this policy.
LocalAbstractObject	getPivot() Returns the pivot for ball partitioning.
float[]	getRadii() Returns the array of radii used for the multi-way ball partitioning.
int	match(BallRegion region) Returns the index of partition to which the whole ball region belongs.
int	match(LocalAbstractObject object) Returns the index of partition to which the object belongs.
void	setPivot(LocalAbstractObject pivot) Sets the pivot for ball partitioning.
void	setRadii(float[] radii) Sets the radii for multi-way ball partitioning.

Methods inherited from class messif.buckets.split.SplitPolicy

getBucketBallRegion, getParameter, getParameterNames, getParameterType, isComplete, isParameterFilled, isParameterLocked, lockParameter, match, setParameter

Methods inherited from class java.lang.Object

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

Field Detail

pivot

protected LocalAbstractObject pivot

Policy parameter pivot

radii

protected float[] radii

Policy parameter radius

dist

protected float dist

The distance to the pivot computed by the last call to match(Region).

Constructor Detail

SplitPolicyMultiWayBallPartitioning

public SplitPolicyMultiWayBallPartitioning()

Creates a new instance of SplitPolicyBallPartitioning

Method Detail

setPivot

public void setPivot(LocalAbstractObject pivot)

Sets the pivot for ball partitioning.

Parameters:

pivot - the pivot

getPivot

public LocalAbstractObject getPivot()

Returns the pivot for ball partitioning.

Returns:

the pivot for ball partitioning

setRadii

public void setRadii(float[] radii)

Sets the radii for multi-way ball partitioning.

Parameters:

radii - the array of radii

getRadii

public float[] getRadii()

Returns the array of radii used for the multi-way ball partitioning.

Returns:

the array of radii

getDistanceToPivot

public float getDistanceToPivot()

Returns the distance to the pivot which might have been computed by the last call to match(Region). If it is equal to LocalAbstractObject.UNKNOWN_DISTANCE, the distance was not evaluated.

Returns:

the distance to the pivot

match

public int match(LocalAbstractObject object)

Returns the index of partition to which the object belongs.

Specified by:

match in interface ObjectMatcher<LocalAbstractObject>

Specified by:

match in class SplitPolicy

Parameters:

object - an object that is tested for partition

Returns:

partition identification (index)

getPartitionsCount

public int getPartitionsCount()

Returns the number of partitions of this policy.

Specified by:

getPartitionsCount in class SplitPolicy

Returns:

the number of partitions of this policy

match

public int match(BallRegion region)

Returns the index of partition to which the whole ball region belongs. Returns -1 if not all objects from the specified ball region fall into just one partition or if this policy cannot decide. In that case, the ball region must be searched one object by one using the match(LocalAbstractObject) method.

Specified by:

match in class SplitPolicy

Parameters:

region - a ball region that is tested for the matching condition

Returns:

the index of partition in which the ball region is contained completely or -1 if it is uncertain