A two-level two-way partitioning algorithm

A two-way partitioning algorithm is presented which significantly improves on the highly unstable results from the traditional Kernighan-Lin based algorithms. The algorithm groups strongly connected components into clusters, and rearranges the clusters into two final subsets with specified sizes. It is known that the grouping operations reduce the complexity and thus improve the results of partitioning very large circuits. However, if the grouping is inappropriate, the partitioning results may degenerate. To prevent degeneration, the authors use a ratio cut approach to do the grouping. By a series of experiments based on the tradeoff between cut capacity and CPU time, the authors determine an optimal value to control the resultant number of groups. Good experimental results have been observed in terms of cut capacity and CPU time.>