public Explanation explain(int doc,Explanation freq) throws IOException {
  return Explanation.match(score(doc,freq.getValue()),"score(doc=" + doc + ",freq="+ freq.getValue()+ "), with freq of:",Collections.singleton(freq));
}

public Explanation explain ( int doc , Explanation freq ) throws IOException { return Explanation . match ( score ( doc , freq . getValue ( ) ) , "score(doc=" + doc + ",freq=" + freq . getValue ( ) + "), with freq of:" , Collections . singleton ( freq ) ) ; }
explain the score for a single document
