org.terrier.matching.models

Class SingleFieldModel

java.lang.Object

org.terrier.matching.models.WeightingModel

org.terrier.matching.models.SingleFieldModel

All Implemented Interfaces:

Serializable, Cloneable, Model

public class SingleFieldModel
extends WeightingModel

Use a normal weighting model on a pre-determine subset of the field. Assumes that IDF can be calculated from all fields, but that TFc comes from the specified fields. Usage: trec.model=SingleFieldModel(PL2,2)

Since:

4.0

Author:

Craig Macdonald

See Also:

Serialized Form

Field Summary

Fields inherited from class org.terrier.matching.models.WeightingModel

averageDocumentLength, c, cs, documentFrequency, es, i, keyFrequency, numberOfDocuments, numberOfPointers, numberOfTokens, numberOfUniqueTerms, rq, termFrequency

Constructor Summary

Constructors

Constructor and Description
SingleFieldModel(String[] parameters)

Method Summary

Methods

Modifier and Type	Method and Description
SingleFieldModel	clone() Clone this weighting model
String	getInfo() Returns the name of the model.
void	prepare() prepare
double	score(double tf, double docLength) This method provides the contract for implementing weighting models.
double	score(double tf, double docLength, double n_t, double F_t, double keyFrequency) This method provides the contract for implementing weighting models.
double	score(Posting _p) Returns score
void	setCollectionStatistics(CollectionStatistics _cs) Sets collection statistics
void	setEntryStatistics(EntryStatistics _es) Sets entry statistics.
void	setParameter(double c) Sets the c value

Methods inherited from class org.terrier.matching.models.WeightingModel

getOverflowed, getParameter, setKeyFrequency, setRequest

Methods inherited from class java.lang.Object

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

Constructor Detail

SingleFieldModel

public SingleFieldModel(String[] parameters)
                 throws Exception

Throws:

Exception

Method Detail

clone

public SingleFieldModel clone()

Description copied from class: WeightingModel

Clone this weighting model

Overrides:

clone in class WeightingModel

prepare

public void prepare()

Description copied from class: WeightingModel

prepare

Overrides:

prepare in class WeightingModel

score

public double score(Posting _p)

Description copied from class: WeightingModel

Returns score

Overrides:

score in class WeightingModel

Returns:

score

setCollectionStatistics

public void setCollectionStatistics(CollectionStatistics _cs)

Description copied from class: WeightingModel

Sets collection statistics

Overrides:

setCollectionStatistics in class WeightingModel

setEntryStatistics

public void setEntryStatistics(EntryStatistics _es)

Description copied from class: WeightingModel

Sets entry statistics.

Overrides:

setEntryStatistics in class WeightingModel

getInfo

public String getInfo()

Description copied from class: WeightingModel

Returns the name of the model.

Specified by:

getInfo in interface Model

Specified by:

getInfo in class WeightingModel

Returns:

java.lang.String

score

public double score(double tf,
           double docLength)

Description copied from class: WeightingModel

This method provides the contract for implementing weighting models.

Specified by:

score in class WeightingModel

Parameters:

tf - The term frequency in the document

docLength - the document's length

Returns:

the score assigned to a document with the given tf and docLength, and other preset parameters

score

public double score(double tf,
           double docLength,
           double n_t,
           double F_t,
           double keyFrequency)

Description copied from class: WeightingModel

This method provides the contract for implementing weighting models. As of Terrier 3.6, the 5-parameter score method is being deprecated since is is not used. The two parameter score method should be used instead. Tagged for removal in a later version.

Specified by:

score in class WeightingModel

Parameters:

tf - The term frequency in the document

docLength - the document's length

n_t - The document frequency of the term

F_t - the term frequency in the collection

keyFrequency - the term frequency in the query

Returns:

the score returned by the implemented weighting model.

setParameter

public void setParameter(double c)

Description copied from class: WeightingModel

Sets the c value

Specified by:

setParameter in interface Model

Overrides:

setParameter in class WeightingModel

Parameters:

c - the term frequency normalisation parameter value.