org.openimaj.lsh.sketch

Class ByteLSHSketcher<OBJECT>

java.lang.Object

org.openimaj.lsh.sketch.ByteLSHSketcher<OBJECT>

Type Parameters:

OBJECT - Type of object being sketched

All Implemented Interfaces:

Sketcher<OBJECT,byte[]>

public class ByteLSHSketcher<OBJECT>
extends Object
implements Sketcher<OBJECT,byte[]>

A Sketcher that produces bit-string sketches encoded as byte arrays. Only the least-significant bit of each hash function will be appended to the final sketch. The length of the output array will be computed such that the bit from each hash function is contained.

Author:

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

Constructor Summary

Constructors

Constructor and Description
ByteLSHSketcher(HashFunction<OBJECT> first, HashFunction<OBJECT>... remainder) Construct with the given functions.
ByteLSHSketcher(HashFunctionFactory<OBJECT> factory, int nFuncs) Construct with the factory which is used to produce the required number of functions.
ByteLSHSketcher(List<HashFunction<OBJECT>> functions) Construct with the given functions.

Method Summary

Modifier and Type	Method and Description
int	arrayLength() Get the length of the output byte array of packed bits.
int	bitLength() Get the length of the sketch in bits.
byte[]	createSketch(OBJECT input) Create a sketch for the given object.

Methods inherited from class java.lang.Object

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

Constructor Detail

ByteLSHSketcher

public ByteLSHSketcher(List<HashFunction<OBJECT>> functions)

Construct with the given functions.

Parameters:

functions - the underlying hash functions.

ByteLSHSketcher

@SafeVarargs
public ByteLSHSketcher(HashFunction<OBJECT> first,
                                    HashFunction<OBJECT>... remainder)

Construct with the given functions.

Parameters:

first - the first function

remainder - the remainder of the functions

ByteLSHSketcher

public ByteLSHSketcher(HashFunctionFactory<OBJECT> factory,
                       int nFuncs)

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

Parameters:

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

nFuncs - the number of functions to create for the composition

Method Detail

createSketch

public byte[] createSketch(OBJECT input)

Description copied from interface: Sketcher

Create a sketch for the given object.

Specified by:

createSketch in interface Sketcher<OBJECT,byte[]>

Parameters:

input - the object to sketch

Returns:

the sketch of the object.

bitLength

public int bitLength()

Get the length of the sketch in bits.

Returns:

the number of bits in the sketch

arrayLength

public int arrayLength()

Get the length of the output byte array of packed bits.

Returns:

the number of bytes that will be returned.