code: public double fBeta(double beta, int outputNum) {
          assertIndex(outputNum);
          double precision = precision(outputNum);
          double recall = recall(outputNum);
          return EvaluationUtils.fBeta(beta, precision, recall);
      }
docs: Calculate the F-beta value for the given output
  
  @param beta      Beta value to use
  @param outputNum Output number
  @return F-beta for the given output