Abstract

Consistency techniques can significantly reduce the search space of constraint satisfaction problems (CSP). In particular, arc-consistency algorithms, such as AC-3 [7], AC-4 [8] and AC-6 [2], have been designed. In [9], we presented DisAC-4, a coarse-grained parallel algorithm designed for distributed memory computer using message passing, which is a distributed version of AC-4. We extend here this result. We design DisAC-3 and DisAC-6. The communication scheme is also extended to allow communication during the propagation step of the consistency algorithms. All these algorithms were systematically experimented. An analysis of the different experiments shows that, as in the sequential case, DisAC-6 provides the best performance and that DisAC-3 outperforms DisAC-4 on most tests. All the distributed algorithms shows a linear speedup. This lead to the conclusion that DisAC-6 is a good candidate for distributed arc-consistency.

Citations