BasicModel (Lucene 7.7.0 API)

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

Direct Known Subclasses:

BasicModelBE, BasicModelD, BasicModelG, BasicModelIF, BasicModelIn, BasicModelIne, BasicModelP
```
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 Concrete Methods
Modifier and Type	Method	Description
`Explanation`	`explain(BasicStats stats, float tfn)`	Returns an explanation for the score.
`abstract float`	`score(BasicStats stats, float tfn)`	Returns the informative content score.
`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 float score(BasicStats stats,
                            float tfn)
```
    Returns the informative content score.
  - explain
```
public Explanation explain(BasicStats stats,
                           float tfn)
```
    Returns an explanation for the score.
    Most basic models use the number of documents and the total term frequency to compute Inf₁. This method provides a generic explanation for such models. Subclasses that use other statistics 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