BasicModel (Lucene 9.11.1 core API)

java.lang.Object
- org.apache.lucene.search.similarities.BasicModel

Direct Known Subclasses:

BasicModelG, BasicModelIF, BasicModelIn, BasicModelIne
```
public abstract class BasicModel
extends Object
```
This class acts as the base class for the specific basic model implementations in the DFR framework. Basic models compute the informative content Inf₁ = -log₂Prob₁ .

See Also:

DFRSimilarity

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

Constructor Summary

Constructors
Constructor Description

BasicModel()
Sole constructor.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`abstract Explanation`	`explain(BasicStats stats, double tfn, double aeTimes1pTfn)`	Returns an explanation for the score.
`abstract double`	`score(BasicStats stats, double tfn, double aeTimes1pTfn)`	Returns the informative content score combined with the after effect, more specifically `informationContentScore * aeTimes1pTfn / (1 + tfn)`.
`abstract String`	`toString()`	Subclasses must override this method to return the code of the basic model formula.

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

- Constructor Detail
  - BasicModel
```
public BasicModel()
```
    Sole constructor. (For invocation by subclass constructors, typically implicit.)
- Method Detail
  - score
```
public abstract double score(BasicStats stats,
                             double tfn,
                             double aeTimes1pTfn)
```
    Returns the informative content score combined with the after effect, more specifically informationContentScore * aeTimes1pTfn / (1 + tfn). This function must be non-decreasing with tfn.
  - explain
```
public abstract Explanation explain(BasicStats stats,
                                    double tfn,
                                    double aeTimes1pTfn)
```
    Returns an explanation for the score. Subclasses must override this method.
  - toString
```
public abstract String toString()
```
    Subclasses must override this method to return the code of the basic model formula. Refer to the original paper for the list.
    
    Overrides:
    
    toString in class Object