docs: public static <E extends SpatialComparable, A> double[] unionFlatMBR(A data, ArrayAdapter<E, ? super A> getter) {
      final int num = getter.size(data);
      assert (num > 0) : "Cannot compute MBR of empty set.";
      final int dim;
      final double[] mbr;
      { // First entry
        final E first = getter.get(data, 0);
        dim = first.getDimensionality();
        mbr = new double[2 * dim];
        for(int d = 0; d < dim; d++) {
          mbr[d] = first.getMin(d);
          mbr[dim + d] = first.getMax(d);
        }
      } // Remaining entries
      for(int i = 1; i < num; i++) {
        E next = getter.get(data, i);
        for(int d = 0; d < dim; d++) {
          mbr[d] = Math.min(mbr[d], next.getMin(d));
          mbr[dim + d] = Math.max(mbr[dim + d], next.getMax(d));
        }
      }
      return mbr;
    }