org.tinspin.index.qtplain

Class QuadTreeKD0<T>

java.lang.Object

org.tinspin.index.qtplain.QuadTreeKD0<T>

Type Parameters:

T -

All Implemented Interfaces:

Index<T>, PointIndex<T>

public class QuadTreeKD0<T>
extends Object
implements PointIndex<T>

A simple MX-quadtree implementation with configurable maximum depth, maximum nodes size, and (if desired) automatic guessing of root rectangle. This version of the quadtree stores for each node only the center point and the distance (radius) to the edges. This reduces space requirements but increases problems with numerical precision. Overall it is more space efficient and slightly faster.

Author:

ztilmann

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	QuadTreeKD0.QIterator<T> Resettable query iterator.
static class	QuadTreeKD0.QStats 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> QuadTreeKD0<T>	create(int dims)
static <T> QuadTreeKD0<T>	create(int dims, int maxNodeSize)
static <T> QuadTreeKD0<T>	create(int dims, int maxNodeSize, double[] center, double radius)
int	getDepth()
int	getDims()
int	getNodeCount()
QuadTreeKD0.QStats	getStats()
void	insert(double[] key, T value) Insert a key-value pair.
QueryIterator<PointEntry<T>>	iterator()
List<QEntryDist<T>>	knnQuery(double[] center, int k)
QuadTreeKD0.QIterator<T>	query(double[] min, double[] max) Query the tree, returning all points in the axis-aligned rectangle between 'min' and 'max'.
T	queryExact(double[] key) Get the value associates with the key.
org.tinspin.index.qtplain.QuadTreeKD0.QQueryIteratorKNN	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

Methods inherited from interface org.tinspin.index.PointIndex

query1NN

Field Detail

DEBUG

public static final boolean DEBUG

See Also:

Constant Field Values

Method Detail

create

public static <T> QuadTreeKD0<T> create(int dims)

create

public static <T> QuadTreeKD0<T> create(int dims,
                                        int maxNodeSize)

create

public static <T> QuadTreeKD0<T> create(int dims,
                                        int maxNodeSize,
                                        double[] center,
                                        double radius)

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 QuadTreeKD0.QIterator<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

knnQuery

public List<QEntryDist<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 QuadTreeKD0.QStats getStats()

Specified by:

getStats in interface Index<T>

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.

queryKNN

public org.tinspin.index.qtplain.QuadTreeKD0.QQueryIteratorKNN 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>