code: protected double getMaxRelativeNodeWidth(double[][] nodeRanges,
        double[][] universe) {
      int widest = widestDim(nodeRanges, universe);
      if(widest < 0)
      	return 0.0;
      else
      	return nodeRanges[widest][WIDTH] / universe[widest][WIDTH];
    }
docs: Returns the maximum attribute width of instances/points
  in a KDTreeNode relative to the whole dataset.
  
  @param nodeRanges The attribute ranges of the
  KDTreeNode whose maximum relative width is to be
  determined.
  @param universe The attribute ranges of the whole
  dataset (training instances + test instances so
  far encountered).
  @return The maximum relative width