Quadratic placement with single-iteration linear system solver

Abstract

In this work we develop a new quadratic placement technique where we prematurely interrupt the linear system solver to interleave the spreading forces saving runtime. This has low impact in the placement flow due to the expand-contract phenomena intrinsic to the ICCG solver outlined in this paper. A coloring scheme for placement, useful for comparing visually placement results, is described. The coloring scheme is then used to create a partitioning strategy that provides a better global view to our placement technique. Our placer based on the ideas developed in this paper is 25% faster for the largest ISPD 2002 benchmarks than FastPlace 3 with no significant penalty in wirelength.