Maintaining Generalized Arc Consistency on Ad-Hoc n-Ary Boolean Constraints

Binary decision diagrams (BDDs) can compactly rep-resent ad-hoc n-ary Boolean constraints. However, there is no gen-eralized arc consistency (GAC) algorithm which exploit BDDs. For example, the global case constraint by SICStus Prolog for ad-hoc constraints is designed for non-Boolean domains. In this paper, we introduce a new GAC algorithm, bddc, for BDD constraints. Our empirical results demonstrate the advantages of a new BDD-based global constraint --bddc is more efficient both in terms of mem-ory and time than the case constraint when dealing with ad-hoc Boolean constraints. This becomes important as the size of the ad-hoc constraints becomes large.