code: private void add2MBR(int[] entrySorting, List<Heap<DoubleIntPair>> pqUB, List<Heap<DoubleIntPair>> pqLB, int index) {
      SpatialComparable currMBR = node.getEntry(entrySorting[index]);
      for(int d = 0; d < currMBR.getDimensionality(); d++) {
        double max = currMBR.getMax(d);
        pqUB.get(d).add(new DoubleIntPair(max, index));
        double min = currMBR.getMin(d);
        pqLB.get(d).add(new DoubleIntPair(min, index));
      }
    }
docs: Adds the minimum and maximum bounds of the MBR of entry number
  <code>entrySorting[index]</code> to the dimension-wise
  upper and lower bound priority queues <code>pqUBFirst</code> and
  <code>pqLBFirst</code>.
  
  @param entrySorting a sorting providing the mapping of <code>index</code>
  to the entry to be added
  @param pqUB One priority queue for each dimension. They are sorted by upper
  bound in descending order and consist of entry indices in
  <code>entrySorting</code> for the entries belonging to
  <code>mbr</code>.
  @param pqLB One priority queue for each dimension. They are sorted by lower
  bound in ascending order and consist of entry indices in
  <code>entrySorting</code> for the entries belonging to
  <code>mbr</code>.
  @param index the index in the sorting referencing the entry to be added