A Comparison of Parallel Approaches for Algebraic Factorization in Logic Synthesis

Algebraic factorization is an extremely important part of any logic synthesis system but is computationally expensive. Hence it is important to look at parallel processing to speed up the procedure. This paper presents three different parallel algorithms for algebraic factorization. The first algorithm uses circuit replication and uses a divide and conquer strategy. A second algorithm uses totally independent factorization on different circuit partitions with no interactions among the partitions. A third algorithm represents a compromise between the two approaches. It uses a novel L-shaped partitioning strategy which provides some interaction among the rectangles obtained in various partitions. For a large circuit like ex1010, the last algorithm runs 11.5 times faster over the sequential kernel extraction algorithms of SIS on 6 processors with less than 0.2 % degradation in quality of the results.