Package org.apache.lucene.search.similarities

# Class Independence

java.lang.Object
org.apache.lucene.search.similarities.Independence

Direct Known Subclasses:
  `IndependenceChiSquared`, `IndependenceSaturated`, `IndependenceStandardized`

public abstract class Independence extends Object
Computes the measure of divergence from independence for DFI scoring functions.

See http://trec.nist.gov/pubs/trec21/papers/irra.web.nb.pdf for more information on different methods.

WARNING: This API is experimental and might change in incompatible ways in the next release.

## Constructor Summary

Constructors
Constructor
Description
`Independence()`
Sole constructor.

## Method Summary

Modifier and Type
Method
Description
`abstract double`
`score(double freq, double expected)`
Computes distance from independence
`abstract String`
`toString()`

### Methods inherited from class java.lang.Object

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

## Constructor Details

### Independence

public Independence()
Sole constructor. (For invocation by subclass constructors, typically implicit.)

## Method Details

### score

public abstract double score(double freq, double expected)
Computes distance from independence

Parameters:
  `freq` - actual term frequency
  `expected` - expected term frequency

### toString

public abstract String toString()

Overrides:
  `toString` in class `Object`