org.apache.lucene.search.similarities

## Class NormalizationZ

- java.lang.Object
- - org.apache.lucene.search.similarities.Normalization
  - - org.apache.lucene.search.similarities.NormalizationZ

-     public class NormalizationZ
      extends Normalization

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

- - ### Nested Class Summary

    - ### Nested classes/interfaces inherited from class org.apache.lucene.search.similarities.Normalization

      `Normalization.NoNormalization`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `NormalizationZ()` Calls `NormalizationZ(0.3)`
    `NormalizationZ(float z)` Creates NormalizationZ with the supplied parameter `z`.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `float` | `getZ()` Returns the parameter `z`
    `float` | `tfn(BasicStats stats, float tf, float len)` Returns the normalized term frequency.
    `String` | `toString()` Subclasses must override this method to return the code of the normalization formula.

    - ### Methods inherited from class org.apache.lucene.search.similarities.Normalization

      `explain`

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

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

- - ### Constructor Detail

    - #### NormalizationZ

          public NormalizationZ()

      Calls `NormalizationZ(0.3)`

    - #### NormalizationZ

          public NormalizationZ(float z)

      Creates NormalizationZ with the supplied parameter `z`.
      Parameters:
        `z` - represents `A/(A+1)` where `A` measures the specificity of the language.

  - ### Method Detail

    - #### tfn

          public float tfn(BasicStats stats,
                           float tf,
                           float len)

      Description copied from class: `Normalization`
      Returns the normalized term frequency.
      Specified by:
        `tfn` in class `Normalization`
        `len` - the field length.

    - #### toString

          public String toString()

      Description copied from class: `Normalization`
      Subclasses must override this method to return the code of the normalization formula. Refer to the original paper for the list.
      Specified by:
        `toString` in class `Normalization`

    - #### getZ

          public float getZ()

      Returns the parameter `z`
      See Also:
        `NormalizationZ(float)`

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