*/
protected void rankMedianPosition(int rankValue,
JGraphHierarchyModel model, int nextRankValue) {
JGraphHierarchyRank rankSet = (JGraphHierarchyRank) model.ranks
.get(new Integer(rankValue));
Object[] rank = rankSet.toArray();
// Form an array of the order in which the cell are to be processed
// , the order is given by the weighted sum of the in or out edges,
// depending on whether we're travelling up or down the hierarchy.
WeightedCellSorter[] weightedValues = new WeightedCellSorter[rank.length];
Map cellMap = new Hashtable(rank.length);