Computes a score factor based on a term or phrase's frequency in a document. This value is multiplied by the {@link #idf(long,long)}factor for each term in the query and these products are then summed to form the initial score for a document.
Terms and phrases repeated in a document indicate the topic of the document, so implementations of this method usually return larger values when freq
is large, and smaller values when freq
is small.
The default implementation calls {@link #tf(float)}.
@param freq the frequency of a term within a document
@return a score factor based on a term's within-document frequency