An Improved Two-Way Partitioning Algorithm with Stable Performance Chung-Kuan Cheng Yen-Chuen A. Wei

Motivation KL based Algorithms highly sensitive to initial conditions Can be solved by multiple runs of the Algorithm Probability of finding good initial conditions drop exponentially with circuit size

Tools(1) – Ratio Cut Two way partitioning Algorithm Finds partitioning with best ratio using RAB = CAB / (|A| x |B|) Partitioning not necessarily even

Tools(2) - FM Fiduccia-Mattheyses Partitioning Move node with best gain that satisfies the balance condition from one partition to the other until all are locked

Step One - Divide Divide the design into two partitions using ratio cut Keep applying ratio cut to any partition larger than #Nodes/g Authors suggest g = 50

Step Two – Conquer Form Supernodes Partition Supernodes using FM number_of_reps times using size constraints Authors suggest 10 for number_of_reps Choose best results from FM

Step Three – Clean Up Expand the Supernodes back out Apply one more run of FM

Experimental Results