Multilevel circuit clustering for delay minimization

Abstract

In this paper, an effective algorithm is presented for multilevel circuit clustering for delay minimization, and is applicable to hierarchical field programmable gate arrays. With a novel graph contraction technique, which allows some crucial delay information of a lower-level clustering to be maintained in the contracted graph, our algorithm recursively divides the lower-level clustering into the next higher-level one in a way that each recursive clustering step is accomplished by applying a modified single-level circuit clustering algorithm based on [1]. We test our algorithm on the two-level clustering problem and compare it with the latest algorithm in [2]. Experimental results show that our algorithm achieves, on average, 12% more delay reduction when compared to the best results (from TLC with full node-duplication) in [2]. In fact, our algorithm is the first one for the general multilevel circuit clustering problem with more than two levels.