Package org.apache.lucene.search.similarities

# Class NormalizationH1

java.lang.Object
org.apache.lucene.search.similarities.Normalization
org.apache.lucene.search.similarities.NormalizationH1

public class NormalizationH1 extends Normalization
Normalization model that assumes a uniform distribution of the term frequency.

While this model is parameterless in the original article, information-based models (see `IBSimilarity`) introduced a multiplying factor. The default value for the `c` parameter is `1`.

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
Description
`NormalizationH1()`
Calls `NormalizationH1(1)`
`NormalizationH1(float c)`
Creates NormalizationH1 with the supplied parameter `c`.

## Method Summary

Modifier and Type
Method
Description
`Explanation`
`explain(BasicStats stats, double tf, double len)`
Returns an explanation for the normalized term frequency.
`float`
`getC()`
Returns the `c` parameter.
`final double`
`tfn(BasicStats stats, double tf, double 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 java.lang.Object

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

## Constructor Details

### NormalizationH1

public NormalizationH1(float c)
Creates NormalizationH1 with the supplied parameter `c`.

Parameters:
  `c` - hyper-parameter that controls the term frequency normalization with respect to the document length.

### NormalizationH1

public NormalizationH1()
Calls `NormalizationH1(1)`

## Method Details

### tfn

public final double tfn(BasicStats stats, double tf, double len)
Description copied from class: `Normalization`
Returns the normalized term frequency.

Specified by:
  `tfn` in class `Normalization`
Parameters:
  `len` - the field length.

### explain

public Explanation explain(BasicStats stats, double tf, double len)
Description copied from class: `Normalization`
Returns an explanation for the normalized term frequency.

The default normalization methods use the field length of the document and the average field length to compute the normalized term frequency. This method provides a generic explanation for such methods. Subclasses that use other statistics must override this method.

Overrides:
  `explain` in class `Normalization`

### 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`

### getC

public float getC()
Returns the `c` parameter.

See Also:
  - `NormalizationH1(float)`