WSSA: A high performance simulated annealing and its application to transistor placement
Another high performance simulated annealing is proposed which we call widely stepping simulated annealing (WSSA). It flies from a starting high temperature to a finishing low temperature staying at only twenty or so temperatures to approach thermal equilibriums. We survey the phase transition in simulated annealing process and estimate the major cost variation (dE(c)) at the critical temperature. The WSSA uses a function (H(t)) that represents the probability for a hill-climbing with the dE(c) of cost increase to be accepted in Metropolis' Monte Carlo simulation at temperature t. We have applied the first version of WSSA to one dimensional transistor placement optimizations for several industrial standard cells, and compared its performance with simulated annealing with a geometrically scheduled cooling. The solutions by the WSSA are as good as and sometimes much better than the solutions by the simulated annealing, while the time consumption by the WSSA is properly under one 30th of that of the simulated annealing.
simulated annealing phase transition placement optimization temperature scheduling cell synthesis