java.lang.Object
- org.terrier.matching.models.WeightingModel

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, Model

Direct Known Subclasses:

BB2, BM25, CoordinateMatch, DFIC, DFIZ, DFR_BM25, DFRee, DFReeKLIM, DFRWeightingModel, DirichletLM, Dl, DLH, DLH13, DPH, Hiemstra_LM, IFB2, In_expB2, In_expC2, InB2, InL2, Js_KLs, LemurTF_IDF, LGD, MDL2, ML2, MRF, Null, pBiL, PerFieldNormWeightingModel, PL2, RequiredTermModifier, SingleFieldModel, StaticScoreModifierWeightingModel, TermInFieldModifier, Tf, TF_IDF, XSqrA_M
```
public abstract class WeightingModel
extends java.lang.Object
implements Model, java.io.Serializable, java.lang.Cloneable
```
This class should be extended by the classes used for weighting terms and documents.

Author:

Gianni Amati, Ben He, Vassilis Plachouras

See Also:

Serialized Form

Field Summary

Fields
Modifier and Type	Field	Description
`protected double`	`averageDocumentLength`	The average length of documents in the collection.
`protected double`	`c`	The parameter c.
`protected CollectionStatistics`	`cs`
`protected double`	`documentFrequency`	The document frequency of the term in the collection.
`protected EntryStatistics`	`es`
`protected Idf`	`i`	The class used for computing the idf values.
`protected double`	`keyFrequency`	The term frequency in the query.
`protected double`	`numberOfDocuments`	The number of documents in the collection.
`protected double`	`numberOfPointers`	Deprecated.
`protected double`	`numberOfPostings`	The number of distinct entries in the inverted file.
`protected double`	`numberOfTokens`	The number of tokens in the collections.
`protected double`	`numberOfUniqueTerms`	Number of unique terms in the collection
`protected Request`	`rq`
`protected double`	`termFrequency`	The term frequency in the collection.

Constructor Summary

Constructors
Constructor Description

WeightingModel()
A default constructor that initialises the idf i attribute

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`WeightingModel`	`clone()`	Clone this weighting model
`abstract java.lang.String`	`getInfo()`	Returns the name of the model.
`static long`	`getOverflowed(int o)`	Returns overflow
`double`	`getParameter()`	Returns the parameter as set by setParameter()
`void`	`prepare()`	prepare
`abstract double`	`score(double tf, double docLength)`	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`	`setKeyFrequency(double keyFreq)`	Sets the term's frequency in the query.
`void`	`setParameter(double _c)`	Sets the c value
`void`	`setRequest(Request _rq)`	Sets request

Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - i
```
protected Idf i
```
    The class used for computing the idf values.
  - averageDocumentLength
```
protected double averageDocumentLength
```
    The average length of documents in the collection.
  - keyFrequency
```
protected double keyFrequency
```
    The term frequency in the query.
  - documentFrequency
```
protected double documentFrequency
```
    The document frequency of the term in the collection.
  - termFrequency
```
protected double termFrequency
```
    The term frequency in the collection.
  - numberOfDocuments
```
protected double numberOfDocuments
```
    The number of documents in the collection.
  - numberOfTokens
```
protected double numberOfTokens
```
    The number of tokens in the collections.
  - c
```
protected double c
```
    The parameter c. This defaults to 1.0, but should be set using in the constructor of each child weighting model to the sensible default for that weighting model.
  - numberOfUniqueTerms
```
protected double numberOfUniqueTerms
```
    Number of unique terms in the collection
  - numberOfPointers
```
@Deprecated
protected double numberOfPointers
```
    Deprecated.
    
    The number of distinct entries in the inverted file. This figure can be calculated as the sum of all Nt over all terms. Deprecated in favour of numberOfPostings
  - numberOfPostings
```
protected double numberOfPostings
```
    The number of distinct entries in the inverted file. This figure can be calculated as the sum of all Nt over all terms
  - cs
```
protected CollectionStatistics cs
```
  - es
```
protected EntryStatistics es
```
  - rq
```
protected Request rq
```
- Constructor Detail
  - WeightingModel
```
public WeightingModel()
```
    A default constructor that initialises the idf i attribute
- Method Detail
  - clone
```
public WeightingModel clone()
```
    Clone this weighting model
    
    Overrides:
    
    clone in class java.lang.Object
  - getInfo
```
public abstract java.lang.String getInfo()
```
    Returns the name of the model.
    
    Specified by:
    
    getInfo in interface Model
    
    Returns:
    
    java.lang.String
  - prepare
```
public void prepare()
```
    prepare
  - getOverflowed
```
public static long getOverflowed(int o)
```
    Returns overflow
    
    Parameters:
    
    o -
    
    Returns:
    
    overflow
  - score
```
public double score(Posting p)
```
    Returns score
    
    Parameters:
    
    p -
    
    Returns:
    
    score
  - setCollectionStatistics
```
public void setCollectionStatistics(CollectionStatistics _cs)
```
    Sets collection statistics
    
    Parameters:
    
    _cs -
  - setEntryStatistics
```
public void setEntryStatistics(EntryStatistics _es)
```
    Sets entry statistics.
    
    Parameters:
    
    _es -
  - setRequest
```
public void setRequest(Request _rq)
```
    Sets request
    
    Parameters:
    
    _rq -
  - score
```
public abstract double score(double tf,
                             double docLength)
```
    This method provides the contract for implementing weighting models.
    
    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
  - setParameter
```
public void setParameter(double _c)
```
    Sets the c value
    
    Specified by:
    
    setParameter in interface Model
    
    Parameters:
    
    _c - the term frequency normalisation parameter value.
  - getParameter
```
public double getParameter()
```
    Returns the parameter as set by setParameter()
    
    Specified by:
    
    getParameter in interface Model
  - setKeyFrequency
```
public void setKeyFrequency(double keyFreq)
```
    Sets the term's frequency in the query.
    
    Parameters:
    
    keyFreq - the term's frequency in the query.

Class WeightingModel

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

i

averageDocumentLength

keyFrequency

documentFrequency

termFrequency

numberOfDocuments

numberOfTokens

c

numberOfUniqueTerms

numberOfPointers

numberOfPostings

cs

es

rq

Constructor Detail

WeightingModel

Method Detail

clone

getInfo

prepare

getOverflowed

score

setCollectionStatistics

setEntryStatistics

setRequest

score

setParameter

getParameter

setKeyFrequency