Package generic.lsh.vector

Class LSHVectorFactory

java.lang.Object

generic.lsh.vector.LSHVectorFactory

Direct Known Subclasses:

WeightedLSHCosineVectorFactory

public abstract class LSHVectorFactory
extends java.lang.Object

Field Summary

Fields

Modifier and Type	Field	Description
protected IDFLookup	idfLookup
protected int	settings
protected WeightFactory	weightFactory

Constructor Summary

Constructors

Constructor	Description
LSHVectorFactory()

Method Summary

Modifier and Type	Method	Description
abstract LSHVector	buildVector(int[] feature)	Generate an LSHVector from a feature set, individual features are integer hashes.
abstract LSHVector	buildZeroVector()	Generate vector with all coefficients zero.
double	calculateSignificance(VectorCompare data)	Given comparison data generated by the LSHVector.compare() method, calculate the significance of any similarity between the two vectors, normalized for this factory's specific weight settings
double	getSelfSignificance(LSHVector vector)	Calculate a vector's significance as compared to itself, normalized for this factory's specific weight settings
int	getSettings()
double	getSignificanceAddend()
double	getSignificanceScale()
boolean	isLoaded()
void	readWeights(XmlPullParser parser)	Read both the weights and the lookup hashes from an XML stream
abstract LSHVector	restoreVectorFromSql(java.lang.String sql)	Generate an LSHVector based on string returned from SQL query Factory generates weights based on term frequency info in the string and its internal IDF knowledge
abstract LSHVector	restoreVectorFromXml(XmlPullParser parser)	Generate an LSHVector based on XML tag seen by pull parser.
void	set(WeightFactory wFactory, IDFLookup iLookup, int settings)	Load the factory with weights and the feature map

Methods inherited from class java.lang.Object

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

Field Detail

weightFactory

protected WeightFactory weightFactory

idfLookup

protected IDFLookup idfLookup

settings

protected int settings

Constructor Detail

LSHVectorFactory

public LSHVectorFactory()

Method Detail

buildZeroVector

public abstract LSHVector buildZeroVector()

Generate vector with all coefficients zero.

Returns:

the zero vector

buildVector

public abstract LSHVector buildVector(int[] feature)

Generate an LSHVector from a feature set, individual features are integer hashes. The integers MUST already be sorted. The same integer can occur more than once in the array (term frequency (TF) > 1). The factory decides internally how to create weights based on term frequency and any knowledge of Inverse Document Frequency (IDF)

Parameters:

feature - is the sorted array of integer features

Returns:

the newly minted LSHVector

restoreVectorFromXml

public abstract LSHVector restoreVectorFromXml(XmlPullParser parser)

Generate an LSHVector based on XML tag seen by pull parser. Factory generates weights based on term frequency info in the XML tag and its internal IDF knowledge

Parameters:

parser - is the XML parser

Returns:

the newly minted LSHVector

restoreVectorFromSql

public abstract LSHVector restoreVectorFromSql(java.lang.String sql)
                                        throws java.io.IOException

Generate an LSHVector based on string returned from SQL query Factory generates weights based on term frequency info in the string and its internal IDF knowledge

Parameters:

sql - is the column data string returned by an SQL query

Returns:

the newly minted LSHVector

Throws:

java.io.IOException

set

public void set(WeightFactory wFactory,
                IDFLookup iLookup,
                int settings)

Load the factory with weights and the feature map

Parameters:

wFactory - is the weight table of IDF and TF weights

iLookup - is the map from features int the weight table

settings - is an integer id for this particular weighting scheme

isLoaded

public boolean isLoaded()

Returns:

true if this factory has weights and lookup loaded

getSignificanceScale

public double getSignificanceScale()

Returns:

the weighttable's significance scale for this factory

getSignificanceAddend

public double getSignificanceAddend()

Returns:

the weighttable's significance addend for this factory

getSettings

public int getSettings()

Returns:

settings ID used to generate factory's current weights

getSelfSignificance

public double getSelfSignificance(LSHVector vector)

Calculate a vector's significance as compared to itself, normalized for this factory's specific weight settings

Parameters:

vector - is the LSHVector

Returns:

the vector's significance score

calculateSignificance

public double calculateSignificance(VectorCompare data)

Given comparison data generated by the LSHVector.compare() method, calculate the significance of any similarity between the two vectors, normalized for this factory's specific weight settings

Parameters:

data - is the comparison object produced when comparing two LSHVectors

Returns:

the significance score

readWeights

public void readWeights(XmlPullParser parser)
                 throws org.xml.sax.SAXException

Read both the weights and the lookup hashes from an XML stream

Parameters:

parser - is the XML parser

Throws:

org.xml.sax.SAXException