Standard cell placement with Dynamic Clouds method

A new procedure for the efficient placement of standard cells is proposed. A procedure based only on the Dynamic Clouds method (see E. Diday et al., 1979) was implemented in a program called Germinal. Germinal proceeds by stages. During the germination stage, germs are selected, and during the growth stage, germs are allowed to grow by clustering cells according to suitable criteria. Germinal uses no initial placement and no generation of pseudorandom numbers for placement and thus converges quite rapidly, which is a major advantage. Experimental results show that the application of this new method improved the wiring cost by 18% on the average, as compared to TimberWolf. With the same benchmarks, it was found that the CPU time decreased by a factor of 36 to 108 times as compared to TimberWolf 4.2. Generally, Germinal converges in six iterations or less