PIN count prediction in ratio cut partitioning for VLSI and ULSI

Partitioning is an important step in computer-aided design. The `ratio cut´ bipartitioning algorithm is known to be one of the best partitioning algorithms. It partitions a circuit into two (disjoint) modules by cutting some of its nets. Based on theoretical arguments, the cost function that is minimized for finding the best partitioning structure in the circuit is set to be the ratio of the number of nets cut to the product of the module sizes. In previous work, we showed that the ratio should contain the number of pins created by all cuts instead of the number of cuts itself to include multi-terminal nets properly. In this paper, we propose a change of the ratio denominator by introducing an accurate estimate of the number of pins resulting from the cuts. We suggest to use Rent´s rule for pin count prediction. Results show improvements over the classical `ratio cut´ algorithm