de.lmu.ifi.dbs.elki.index.lsh.hashfamilies

Class AbstractProjectedHashFunctionFamily

java.lang.Object

de.lmu.ifi.dbs.elki.index.lsh.hashfamilies.AbstractProjectedHashFunctionFamily

All Implemented Interfaces:

LocalitySensitiveHashFunctionFamily<NumberVector>

Direct Known Subclasses:

EuclideanHashFunctionFamily, ManhattanHashFunctionFamily

public abstract class AbstractProjectedHashFunctionFamily
extends Object
implements LocalitySensitiveHashFunctionFamily<NumberVector>

Abstract base class for projection based hash functions.

Author:

Erich Schubert

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	AbstractProjectedHashFunctionFamily.Parameterizer Parameterization class.

Field Summary

Fields

Modifier and Type	Field and Description
protected int	k The number of projections to use for each hash function.
protected RandomProjectionFamily	proj Projection family to use.
protected RandomFactory	random Random generator to use.
protected double	width Width of each bin.

Constructor Summary

Constructors

Constructor and Description
AbstractProjectedHashFunctionFamily(RandomFactory random, RandomProjectionFamily proj, double width, int k) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
ArrayList<? extends LocalitySensitiveHashFunction<? super NumberVector>>	generateHashFunctions(Relation<? extends NumberVector> relation, int l) Generate hash functions for the given relation.
TypeInformation	getInputTypeRestriction() Get the input type information.

Methods inherited from class java.lang.Object

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

Methods inherited from interface de.lmu.ifi.dbs.elki.index.lsh.hashfamilies.LocalitySensitiveHashFunctionFamily

isCompatible

Field Detail

random

protected RandomFactory random

Random generator to use.

proj

protected RandomProjectionFamily proj

Projection family to use.

width

protected double width

Width of each bin.

k

protected int k

The number of projections to use for each hash function.

Constructor Detail

AbstractProjectedHashFunctionFamily

public AbstractProjectedHashFunctionFamily(RandomFactory random,
                                   RandomProjectionFamily proj,
                                   double width,
                                   int k)

Constructor.

Parameters:

random - Random generator

proj - Projection family

width - Bin width

k - Number of projections for each hash function.

Method Detail

generateHashFunctions

public ArrayList<? extends LocalitySensitiveHashFunction<? super NumberVector>> generateHashFunctions(Relation<? extends NumberVector> relation,
                                                                                             int l)

Description copied from interface: LocalitySensitiveHashFunctionFamily

Generate hash functions for the given relation.

Specified by:

generateHashFunctions in interface LocalitySensitiveHashFunctionFamily<NumberVector>

Parameters:

relation - Relation to index

l - Number of hash tables to use

Returns:

Family of hash functions

getInputTypeRestriction

public TypeInformation getInputTypeRestriction()

Description copied from interface: LocalitySensitiveHashFunctionFamily

Get the input type information.

Specified by:

getInputTypeRestriction in interface LocalitySensitiveHashFunctionFamily<NumberVector>

Returns:

Input type information.