LambdaDF (Lucene 9.12.2 core API)

java.lang.Object
- org.apache.lucene.search.similarities.Lambda
- - org.apache.lucene.search.similarities.LambdaDF

```
public class LambdaDF
extends Lambda
```
Computes lambda as docFreq+1 / numberOfDocuments+1.

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

Constructor Summary

Constructors
Constructor Description

LambdaDF()
Sole constructor: parameter-free

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`Explanation`	`explain(BasicStats stats)`	Explains the lambda parameter.
`float`	`lambda(BasicStats stats)`	Computes the lambda parameter.
`String`	`toString()`	Subclasses must override this method to return the code of the lambda formula.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - LambdaDF
```
public LambdaDF()
```
    Sole constructor: parameter-free
- Method Detail
  - lambda
```
public final float lambda(BasicStats stats)
```
    Description copied from class: Lambda
    
    Computes the lambda parameter.
    
    Specified by:
    
    lambda in class Lambda
  - explain
```
public final Explanation explain(BasicStats stats)
```
    Description copied from class: Lambda
    
    Explains the lambda parameter.
    
    Specified by:
    
    explain in class Lambda
  - toString
```
public String toString()
```
    Description copied from class: Lambda
    
    Subclasses must override this method to return the code of the lambda formula. Since the original paper is not very clear on this matter, and also uses the DFR naming scheme incorrectly, the codes here were chosen arbitrarily.
    
    Specified by:
    
    toString in class Lambda