Analysis of Symbolic SCC Hull Algorithms
Fabio Somenzi6
, Kavita Ravi7
and Roderick Bloem8 
| (6) |
University of Colorado at Boulder, USA |
| (7) |
Cadence Design Systems, USA |
| (8) |
Graz University of Technology, Austria |
Abstract
The Generalized SCC Hull (GSH) algorithm of [11] can be instantiated to obtain many symbolic algorithms for the detection of fair cycles in a graph. We present a modified
GSH with improved convergence properties, and we use it to study—both in theory and experimentally—the performance of various
algorithms employed in symbolic model checkers. In particular, we show that the algorithm of Emerson and Lei [4] has optimal complexity among those that can be derived from GSH. We also propose an early termination check that allows
the Lockstep algorithm [1] to detect the existence of a fair cycle before an entire SCC has been examined. Our experimental evaluation confirms that
no one method dominates the others, and identifies some of the factors that impact run times besides those accounted for by
the theoretical analysis.
This work was supported in part by SRC contract 2001-TJ-920 and NSF grant CCR-99-71195.
This work was done while this author was with the University of Colorado at Boulder.
References secured to subscribers.