Abstract

We empirically assess the implications of fixed terminals for hypergraph partitioning heuristics. Our experimental testbed incorporates a leading-edge multilevel hypergraph partitioner [12] [3] and IBM-internal circuits that have recently been released as part of the ISPD-98 Benchmark Suite [2, 1]. We find that the presence of fixed terminals can make a partitioning instance considerably easier (possibly to the point of being "trivial"); much less effort is needed to stably reach solution qualities that are near best-achievable. Toward development of partitioning heuristics specific to the fixed-terminals regime, we study the pass statistics of flat FM-based partitioning heuristics. Our data suggest that more fixed terminals implies that the improvements within a pass will more likely occur near the beginning of the pass. Restricting the length of passes -- which degrades solution quality in the classic (free-hypergraph) context -- is relatively safe for the fixed-terminals regime and ...

Citations