This class implements the DPH hypergeometric weighting model. P
stands for Popper's normalization. This is a parameter-free
weighting model. Even if the user specifies a parameter value, it will NOT
affect the results. It is highly recomended to use the model with query expansion.
FUB, IASI-CNR and University of Tor Vergata at TREC 2007 Blog Track. G. Amati
and E. Ambrosi and M. Bianchi and C. Gaibisso and G. Gambosi. Proceedings of
the 16th Text REtrieval Conference (TREC-2007), 2008.
Frequentist and Bayesian approach to Information Retrieval. G. Amati. In
Proceedings of the 28th European Conference on IR Research (ECIR 2006).
LNCS vol 3936, pages 13--24.
the score assigned to a document with the given
tf and docLength, and other preset parameters
public final double score(double tf,
This method provides the contract for implementing weighting models.
As of Terrier 3.6, the 5-parameter score method is being deprecated
since it is not used. The two parameter score method should be used
instead. Tagged for removal in a later version.