jsat.linear.vectorcollection

Class EuclideanCollection<V extends Vec>

java.lang.Object

jsat.linear.vectorcollection.EuclideanCollection<V>

All Implemented Interfaces:

Serializable, Cloneable, VectorCollection<V>

public class EuclideanCollection<V extends Vec>
extends Object
implements VectorCollection<V>

Provides a specialized collections that only supports the EuclideanDistance by brute force search. It does this more efficiently by decomposing the squared distance into
d(x, y)² = || x - y||² = <x, x> + <y, y> - 2 <x, y>
The shortest distances can then be obtained using only 1 dot product per element, as the input and collection values are cached. This avoids redundant calculations present in the naive approach, and can result in drastic performance increases when using sparse vectors or a mix of dense and sparse vectors.

Author:

Edward Raff

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	EuclideanCollection.EuclideanCollectionFactory<V extends Vec>

Constructor Summary

Constructors

Constructor and Description
EuclideanCollection(EuclideanCollection toCopy) Copy constructor
EuclideanCollection(List<V> source) Creates a new Vector Collection that does an efficient brute force search for only the Euclidean distance.
EuclideanCollection(List<V> source, ExecutorService threadpool) Creates a new Vector Collection that does an efficient brute force search for only the Euclidean distance.

Method Summary

Modifier and Type	Method and Description
EuclideanCollection<V>	clone()
List<? extends VecPaired<V,Double>>	search(Vec query, double range) Searches the space for all vectors that are within a given range of the query vector.
List<? extends VecPaired<V,Double>>	search(Vec query, int neighbors) Searches the space for the k neighbors that are closest to the given query vector
int	size() Returns the number of vectors stored in the collection

Methods inherited from class java.lang.Object

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

Constructor Detail

EuclideanCollection

public EuclideanCollection(List<V> source)

Creates a new Vector Collection that does an efficient brute force search for only the Euclidean distance.

Parameters:

source - the set of vectors to form the collection

EuclideanCollection

public EuclideanCollection(EuclideanCollection toCopy)

Copy constructor

Parameters:

toCopy - the object to copy

EuclideanCollection

public EuclideanCollection(List<V> source,
                           ExecutorService threadpool)

Creates a new Vector Collection that does an efficient brute force search for only the Euclidean distance.

Parameters:

source - the set of vectors to form the collection

threadpool - the source of threads for parallel construction

Method Detail

search

public List<? extends VecPaired<V,Double>> search(Vec query,
                                                  double range)

Description copied from interface: VectorCollection

Searches the space for all vectors that are within a given range of the query vector.

Specified by:

search in interface VectorCollection<V extends Vec>

Parameters:

query - the vector we want to find others near

range - the search range around our query

Returns:

the list of all vectors within the range of our query. The paired value contains the distance to the query vector.

search

public List<? extends VecPaired<V,Double>> search(Vec query,
                                                  int neighbors)

Description copied from interface: VectorCollection

Searches the space for the k neighbors that are closest to the given query vector

Specified by:

search in interface VectorCollection<V extends Vec>

Parameters:

query - the vector we want to find neighbors of

neighbors - the maximum number of neighbors to return

Returns:

the list the k nearest neighbors, in sorted order from closest to farthest. The paired value contains the distance to the query vector

size

public int size()

Description copied from interface: VectorCollection

Returns the number of vectors stored in the collection

Specified by:

size in interface VectorCollection<V extends Vec>

Returns:

the size of the collection

clone

public EuclideanCollection<V> clone()

Specified by:

clone in interface VectorCollection<V extends Vec>

Overrides:

clone in class Object