Package org.apache.lucene.search.similarities

# Class Distribution

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

Direct Known Subclasses:
  `DistributionLL`, `DistributionSPL`

public abstract class Distribution extends Object
The probabilistic distribution used to model term occurrence in information-based models.

See Also:
  - `IBSimilarity`
WARNING: This API is experimental and might change in incompatible ways in the next release.

## Constructor Summary

Constructors
Constructor
Description
`Distribution()`
Sole constructor.

## Method Summary

Modifier and Type
Method
Description
`Explanation`
`explain(BasicStats stats, double tfn, double lambda)`
Explains the score.
`abstract double`
`score(BasicStats stats, double tfn, double lambda)`
Computes the score.
`abstract String`
`toString()`
Subclasses must override this method to return the name of the distribution.

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

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

## Constructor Details

### Distribution

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

## Method Details

### score

public abstract double score(BasicStats stats, double tfn, double lambda)
Computes the score.

### explain

public Explanation explain(BasicStats stats, double tfn, double lambda)
Explains the score. Returns the name of the model only, since both `tfn` and `lambda` are explained elsewhere.

### toString

public abstract String toString()
Subclasses must override this method to return the name of the distribution.

Overrides:
  `toString` in class `Object`