## 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
`Distribution()` Sole constructor.

Method Summary
`Explanation` `explain(BasicStats stats, float tfn, float lambda)` Explains the score.
`abstract float` `score(BasicStats stats, float tfn, float 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 Detail

### Distribution

    public Distribution()

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

Method Detail

### score

    public abstract float score(BasicStats stats,
                                float tfn,
                                float lambda)

  Computes the score.

### explain

    public Explanation explain(BasicStats stats,
                               float tfn,
                               float 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`

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