In this paper, we present a hierarchical ratio partitioning based placement algorithm for large-scale mixed-size designs. The placement algorithm consists of three steps: global placement, legalization,and detailed placement; it works in a hierarchical manner and integrates net-weighting partitioning, whitespace management, look-ahead bipartitioning, and fast legalization to handle the large-scale mixed-size placement problems. Unlike the traditional partitioning-based technique that is based on balanced partitioning, we apply ratio partitioning in each level. Further, applying the look-ahead bipartitioning technique in each level, we can evaluate the feasibility of the placement for sub-partitions more accurately. Therefore, we can find better ratios for the partitions, leading to easier legalization for the global placement result and finally a better detailed placement solution. Experimental results show the efficiency and effectiveness of our algorithm.
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