org.openimaj.lsh.composition

Class RandomProjectionHashComposition<OBJECT>

java.lang.Object

org.openimaj.util.hash.composition.HashComposition<OBJECT>

org.openimaj.lsh.composition.RandomProjectionHashComposition<OBJECT>

Type Parameters:

OBJECT - Object being hashed

All Implemented Interfaces:

HashFunction<OBJECT>

public class RandomProjectionHashComposition<OBJECT>
extends HashComposition<OBJECT>

Compose a set of hash functions by computing the dot product of the hashes they produce with a random vector.

Author:

Jonathon Hare (jsh2@ecs.soton.ac.uk)

Field Summary

Fields inherited from class org.openimaj.util.hash.composition.HashComposition

hashFunctions

Constructor Summary

Constructors

Constructor and Description
RandomProjectionHashComposition(cern.jet.random.engine.MersenneTwister rng, HashFunction<OBJECT> first, HashFunction<OBJECT>... remainder) Construct with the given functions.
RandomProjectionHashComposition(cern.jet.random.engine.MersenneTwister rng, HashFunctionFactory<OBJECT> factory, int nFuncs) Construct with the factory which is used to produce the required number of functions.
RandomProjectionHashComposition(cern.jet.random.engine.MersenneTwister rng, List<HashFunction<OBJECT>> functions) Construct with the given functions.

Method Summary

Modifier and Type	Method and Description
int	computeHashCode(OBJECT object) Compute the hash code for the object

Methods inherited from class java.lang.Object

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

Constructor Detail

RandomProjectionHashComposition

public RandomProjectionHashComposition(cern.jet.random.engine.MersenneTwister rng,
                                       List<HashFunction<OBJECT>> functions)

Construct with the given functions.

Parameters:

rng - the random number generator

functions - the underlying hash functions.

RandomProjectionHashComposition

@SafeVarargs
public RandomProjectionHashComposition(cern.jet.random.engine.MersenneTwister rng,
                                                    HashFunction<OBJECT> first,
                                                    HashFunction<OBJECT>... remainder)

Construct with the given functions.

Parameters:

rng - the random number generator

first - the first function

remainder - the remainder of the functions

RandomProjectionHashComposition

public RandomProjectionHashComposition(cern.jet.random.engine.MersenneTwister rng,
                                       HashFunctionFactory<OBJECT> factory,
                                       int nFuncs)

Construct with the factory which is used to produce the required number of functions.

Parameters:

rng - the random number generator

factory - the factory to use to produce the underlying hash functions.

nFuncs - the number of functions to create for the composition

Method Detail

computeHashCode

public int computeHashCode(OBJECT object)

Description copied from interface: HashFunction

Compute the hash code for the object

Parameters:

object - the object

Returns:

the hash code