Pre-layout Physical Connectivity Prediction with Applications in Clustering, Placement and Logic Synthesis

In this paper, we introduce a structural metric, logic contraction, for pre-layout physical connectivity prediction. For a given set of nodes forming a cluster in a netlist, we can predict their proximity in the final layout. We demonstrate experimentally a very good correlation of our pre-layout measure with the post layout physical distances between those nodes. We show an application of the logic contraction to circuit clustering. We compare our SeedGrowth clustering algorithm with the existing efficient clustering techniques such as Edge-Coarsening [1][12], First-Choice [13] and Peak-Clustering [11]. We apply our clustering technique to speed up a placement tool and sketch out our ideas on how to use it in technology mapping. Experimental results demonstrate the effectiveness of our new clustering method.