ivory.lsh.data

Class MinhashSignature

java.lang.Object

ivory.lsh.data.Signature

ivory.lsh.data.MinhashSignature

All Implemented Interfaces:

Comparable, Writable, WritableComparable

public class MinhashSignature
extends Signature

A version of BitsSignature specifically tuned for 64 bits. Uses an array of 8 bytes instead of the Bits object.

Author:

ferhanture

See Also:

NBitSignature

Constructor Summary

Constructors

Constructor and Description
MinhashSignature() Create a BitsSignature object with the specified number of bits, all initially set to 0.
MinhashSignature(ArrayListOfIntsWritable b)
MinhashSignature(int numTerms)
MinhashSignature(MinhashSignature other)

Method Summary

Methods

Modifier and Type	Method and Description
void	add(int elt)
void	clear()
int	compareTo(MinhashSignature other)
int	compareTo(Object o)
boolean	containsTerm(int i)
boolean	equals(Object o)
int	get(int i)
MinhashSignature	getSubSignature(int b, int e)
MinhashSignature	getSubSignature(int b, int e, Signature subSign)
int	hammingDistance(Signature signature)
int	hammingDistance(Signature signature, int threshold)
int	hashCode()
MinhashSignature	perm(ArrayListOfIntsWritable permutation)
void	perm(ArrayListOfIntsWritable permutation, Signature permSign)
void	readFields(DataInput in)
void	set(int pos, int elt)
void	setTerms(ArrayListOfIntsWritable terms)
int	size()
ArrayListOfIntsWritable	sub(ArrayListOfIntsWritable lst, int start, int end)
String	toString()
void	write(DataOutput out)

Methods inherited from class ivory.lsh.data.Signature

createSignature, getLongestPrefix

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

MinhashSignature

public MinhashSignature()

Create a BitsSignature object with the specified number of bits, all initially set to 0.

MinhashSignature

public MinhashSignature(ArrayListOfIntsWritable b)

MinhashSignature

public MinhashSignature(int numTerms)

MinhashSignature

public MinhashSignature(MinhashSignature other)

Method Detail

add

public void add(int elt)

clear

public void clear()

compareTo

public int compareTo(MinhashSignature other)

compareTo

public int compareTo(Object o)

containsTerm

public boolean containsTerm(int i)

equals

public boolean equals(Object o)

Overrides:

equals in class Object

get

public int get(int i)

getSubSignature

public MinhashSignature getSubSignature(int b,
                               int e)

Specified by:

getSubSignature in class Signature

Parameters:

b - first index to be included in sub-signature

e - last index to be included in sub-signature

Returns:

return a new BitsSignature object, containing the bits of this object from start to end

getSubSignature

public MinhashSignature getSubSignature(int b,
                               int e,
                               Signature subSign)

Specified by:

getSubSignature in class Signature

hammingDistance

public int hammingDistance(Signature signature)

Specified by:

hammingDistance in class Signature

Returns:

compute hamming distance between this object and signature.

hammingDistance

public int hammingDistance(Signature signature,
                  int threshold)

Specified by:

hammingDistance in class Signature

Returns:

compute hamming distance between this object and signature. early terminate if distance exceeds threshold.

hashCode

public int hashCode()

Overrides:

hashCode in class Object

perm

public MinhashSignature perm(ArrayListOfIntsWritable permutation)

Specified by:

perm in class Signature

Returns:

permute this object w.r.t permutation object and return permuted signature

perm

public void perm(ArrayListOfIntsWritable permutation,
        Signature permSign)

Specified by:

perm in class Signature

Parameters:

permutation - permute this object w.r.t permutation object and save permuted signature in permSign

readFields

public void readFields(DataInput in)
                throws IOException

Throws:

IOException

set

public void set(int pos,
       int elt)

setTerms

public void setTerms(ArrayListOfIntsWritable terms)

size

public int size()

Specified by:

size in class Signature

Returns:

number of minhash terms.

See Also:

Signature.size()

sub

public ArrayListOfIntsWritable sub(ArrayListOfIntsWritable lst,
                          int start,
                          int end)

Parameters:

start - first index to be included in sub-list

end - last index to be included in sub-list

Returns:

return a new ArrayListOfIntsWritable object, containing the ints of this object from start to end

toString

public String toString()

Specified by:

toString in class Signature

write

public void write(DataOutput out)
           throws IOException

Throws:

IOException