/** Creates a BM25 scorer using specified <var>k</var><sub>1</sub> and <var>b</var> parameters.
* @param k1 the <var>k</var><sub>1</sub> parameter.
* @param b the <var>b</var> parameter.
*/
public RelevanceModelScorer(final double k1, final double b) {
termVisitor = new TermCollectionVisitor();
setupVisitor = new CounterSetupVisitor( termVisitor );
this.k1 = k1;
this.b = b;
k1Times1MinusB = k1 * ( 1 - b );
}