code: public static double falseNegativeRate(long fnCount, long tpCount, double edgeCase) {
          //Edge case
          if (fnCount == 0 && tpCount == 0) {
              return edgeCase;
          }
  
          return fnCount / (double) (fnCount + tpCount);
      }
docs: Calculate the false negative rate from the false negative counts and true positive count
  
  @param fnCount  False negative count
  @param tpCount  True positive count
  @param edgeCase Edge case value to use to avoid 0/0
  @return False negative rate