Class Normalization

  extended by
Direct Known Subclasses:
Normalization.NoNormalization, NormalizationH1, NormalizationH2, NormalizationH3, NormalizationZ

public abstract class Normalization
extends Object

This class acts as the base class for the implementations of the term frequency normalization methods in the DFR framework.

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

Nested Class Summary
static class Normalization.NoNormalization
          Implementation used when there is no normalization.
Constructor Summary
          Sole constructor.
Method Summary
 Explanation explain(BasicStats stats, float tf, float len)
          Returns an explanation for the normalized term frequency.
abstract  float tfn(BasicStats stats, float tf, float len)
          Returns the normalized term frequency.
abstract  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 Detail


public Normalization()
Sole constructor. (For invocation by subclass constructors, typically implicit.)

Method Detail


public abstract float tfn(BasicStats stats,
                          float tf,
                          float len)
Returns the normalized term frequency.

len - the field length.


public Explanation explain(BasicStats stats,
                           float tf,
                           float len)
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.


public abstract String toString()
Subclasses must override this method to return the code of the normalization formula. Refer to the original paper for the list.

toString in class Object

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