public Geometric2DNodeCollection(){
		// Immediately stop execution if rMax is not defined in the xml config file.  
		try {
			rMax = Configuration.getDoubleParameter("GeometricNodeCollection/rMax");
		} catch(CorruptConfigurationEntryException e) {
			Main.fatalError(e.getMessage());
		}
		
		double ratio = dimX / rMax;
		xDim = (int)Math.ceil(ratio);

		ratio = dimY/rMax;
		yDim = (int)Math.ceil(ratio);
		
		lists = new DLLNodeList[xDim][yDim];
		for(int i = 0; i < xDim; i++){
			for(int j = 0; j < yDim; j++){
				lists[i][j] = new DLLNodeList(true);
			}
		}
	}