org.apache.lucene.search.similarities
Class BasicModelD
java.lang.Object
org.apache.lucene.search.similarities.BasicModel
org.apache.lucene.search.similarities.BasicModelD
public class BasicModelD
- extends BasicModel
Implements the approximation of the binomial model with the divergence
for DFR. The formula used in Lucene differs slightly from the one in the
original paper: to avoid underflow for small values of N
and
F
, N
is increased by 1
and
F
is always increased by tfn+1
.
WARNING: for terms that do not meet the expected random distribution
(e.g. stopwords), this model may give poor performance, such as
abnormally high scores for low tf values.
- WARNING: This API is experimental and might change in incompatible ways in the next release.
Method Summary |
float |
score(BasicStats stats,
float tfn)
Returns the informative content score. |
String |
toString()
Subclasses must override this method to return the code of the
basic model formula. |
Methods inherited from class org.apache.lucene.search.similarities.BasicModel |
explain |
BasicModelD
public BasicModelD()
score
public final float score(BasicStats stats,
float tfn)
- Description copied from class:
BasicModel
- Returns the informative content score.
- Specified by:
score
in class BasicModel
toString
public String toString()
- Description copied from class:
BasicModel
- Subclasses must override this method to return the code of the
basic model formula. Refer to the original paper for the list.
- Specified by:
toString
in class BasicModel
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