Optimizing node numbering

If "Skyline" solver is used, the required memory and the computing time is directly related to the band width of the system equations. The band width i s determined by the node numbering. Therefore, node numbering is very important. However, nodes are numbered initially in the order of their creation during the modeling stage. It is desirable to renumber the nodes before processing stage so that the band width is minimized. This procedure is called node number optimization.

Node number optimization can be dictated as an optional item to be done before processing as explained in the previous section. This option, however, may cause redundant repetition of the operation, if the same modeling data are used for multiple analysis. This redundant operation may be avoided by doing the node number optimization once and executing the processing multiple times without the optimization option.

Node number optimization can be invoked by choosing "Optimize Node Number" item from the menu. A dialog shows the intermediate state of progressive band width reduction and the final half band width (HBW) after the completion of optimization. If you click button, the nodes will be re numbered as optimized. If you click button, the optimization is ignored and the old node numbering will be retained. Save the file in order to keep this renumbering for future processing.

It should be noted that the optimization does not mean absolute minimization of the band width, but means relative reduction of the band width. There may exist a node numbering with smaller band width than the optimized one. However, it is too time consuming or not feasible to find the numbering with this absolute minimum band width.