Performance optimization using separator sets

In this paper, we propose a new method to optimize a performance of a very large circuit. We find the best set of local transformations to be applied to the circuit, by inserting "padding nodes" on noncritical edges of the circuit, and calculating separator sets of the circuit using separator sets. Our method is robust for very large circuits, because its memory usage and calculation time are linear and polynomial order with the size of the circuit. According to our experimental results, our method has accomplished all circuits, while Singh's (1992) selection function method has aborted with three large circuits because of memory overflow. The results also shows our method has a comparable capability in delay optimization to Singh's method.