org.tinspin.index.kdtree

Class KDTree<T>

java.lang.Object

org.tinspin.index.kdtree.KDTree<T>

Type Parameters:

T - Value type

All Implemented Interfaces:

Index<T>, PointIndex<T>

public class KDTree<T>
extends Object
implements PointIndex<T>

A simple KD-Tree implementation.

Author:

T. Zäschke

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	KDTree.KDStats Statistics container class.

Field Summary

Fields

Modifier and Type	Field and Description
static boolean	DEBUG

Method Summary

Modifier and Type	Method and Description
void	clear() Removes all elements from the tree.
boolean	containsExact(double[] key) Check whether a given key exists.
static <T> KDTree<T>	create(int dims)
static <T> KDTree<T>	create(int dims, PointDistanceFunction dist)
int	getDepth()
int	getDims()
int	getNodeCount()
KDTree.KDStats	getStats()
void	insert(double[] key, T value) Insert a key-value pair.
QueryIterator<PointEntry<T>>	iterator()
List<KDEntryDist<T>>	knnQuery(double[] center, int k)
static void	main(String... args)
KDEntryDist<T>	nnQuery(double[] center) 1-nearest neighbor query.
KDIterator<T>	query(double[] min, double[] max) Query the tree, returning all points in the axis-aligned rectangle between 'min' and 'max'.
KDEntryDist<T>	query1NN(double[] center) Finds the nearest neighbor.
T	queryExact(double[] key) Get the value associates with the key.
QueryIteratorKNN<PointEntryDist<T>>	queryKNN(double[] center, int k) Finds the nearest neighbor.
T	remove(double[] key) Remove a key.
int	size() Get the number of key-value pairs in the tree.
String	toString()
String	toStringTree() Returns a printable list of the tree.
T	update(double[] oldKey, double[] newKey) Reinsert the key.

Methods inherited from class java.lang.Object

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

Field Detail

DEBUG

public static final boolean DEBUG

See Also:

Constant Field Values

Method Detail

main

public static void main(String... args)

create

public static <T> KDTree<T> create(int dims)

create

public static <T> KDTree<T> create(int dims,
                                   PointDistanceFunction dist)

insert

public void insert(double[] key,
                   T value)

Insert a key-value pair.

Specified by:

insert in interface PointIndex<T>

Parameters:

key - the key

value - the value

containsExact

public boolean containsExact(double[] key)

Check whether a given key exists.

Parameters:

key - the key to check

Returns:

true iff the key exists

queryExact

public T queryExact(double[] key)

Get the value associates with the key.

Specified by:

queryExact in interface PointIndex<T>

Parameters:

key - the key to look up

Returns:

the value for the key or 'null' if the key was not found

remove

public T remove(double[] key)

Remove a key.

Specified by:

remove in interface PointIndex<T>

Parameters:

key - key to remove

Returns:

the value associated with the key or 'null' if the key was not found

update

public T update(double[] oldKey,
                double[] newKey)

Reinsert the key.

Specified by:

update in interface PointIndex<T>

Parameters:

oldKey - old key

newKey - new key

Returns:

the value associated with the key or 'null' if the key was not found.

size

public int size()

Get the number of key-value pairs in the tree.

Specified by:

size in interface Index<T>

Returns:

the size

clear

public void clear()

Removes all elements from the tree.

Specified by:

clear in interface Index<T>

query

public KDIterator<T> query(double[] min,
                           double[] max)

Query the tree, returning all points in the axis-aligned rectangle between 'min' and 'max'.

Specified by:

query in interface PointIndex<T>

Parameters:

min - lower left corner of query

max - upper right corner of query

Returns:

all entries in the rectangle

nnQuery

public KDEntryDist<T> nnQuery(double[] center)

1-nearest neighbor query.

Parameters:

center - The point for which the nearest neighbors are requested

Returns:

Nearest neighbor

knnQuery

public List<KDEntryDist<T>> knnQuery(double[] center,
                                     int k)

toStringTree

public String toStringTree()

Returns a printable list of the tree.

Specified by:

toStringTree in interface Index<T>

Returns:

the tree as String

toString

public String toString()

Overrides:

toString in class Object

getStats

public KDTree.KDStats getStats()

Specified by:

getStats in interface Index<T>

Returns:

Collect and return some index statistics. Note that indexes are not required to fill all fields. Also, individual indexes may use subclasses with additional fields.

getDims

public int getDims()

Specified by:

getDims in interface Index<T>

Returns:

the number of dimensions

iterator

public QueryIterator<PointEntry<T>> iterator()

Specified by:

iterator in interface PointIndex<T>

Returns:

An iterator over all entries.

query1NN

public KDEntryDist<T> query1NN(double[] center)

Description copied from interface: PointIndex

Finds the nearest neighbor. This uses euclidean distance. Other distance types can only be specified directly on the index implementations.

Specified by:

query1NN in interface PointIndex<T>

Parameters:

center - center point

Returns:

the nearest neighbor

queryKNN

public QueryIteratorKNN<PointEntryDist<T>> queryKNN(double[] center,
                                                    int k)

Description copied from interface: PointIndex

Finds the nearest neighbor. This uses euclidean distance. Other distance types can only be specified directly on the index implementations.

Specified by:

queryKNN in interface PointIndex<T>

Parameters:

center - center point

k - number of neighbors

Returns:

list of nearest neighbors

getNodeCount

public int getNodeCount()

Specified by:

getNodeCount in interface Index<T>

getDepth

public int getDepth()

Specified by:

getDepth in interface Index<T>