Xapian::TradWeight - Traditional Probabilistic Weighting scheme.
Traditional Probabilistic Weighting scheme, as described by the early papers on Probabilistic Retrieval. BM25 generally gives better results.
This class is deprecated - use BM25Weight(k, 0, 0, 1, 0) instead (which it is equivalent to).
Constructor. Either takes no parameters, or a single non-negative parameter k. If k isn't specified, the default value used is 1.