code: public double calculateAverageAUC() {
          assertIndex(0);
  
          double sum = 0.0;
          for (int i = 0; i < underlying.length; i++) {
              sum += calculateAUC(i);
          }
  
          return sum / underlying.length;
      }
docs: Calculate the macro-average (one-vs-all) AUC for all classes