docs: public static int rowNumber(int index, INDArray arr) {
          double otherTest = ((double) index) / arr.size(-1);
          int test = (int) Math.floor(otherTest);
  
          // FIXME: int cast
  
          int vectors = (int) arr.vectorsAlongDimension(-1);
          if (test >= vectors)
              return vectors - 1;
          return test;
      }