Integrating Strong Local Consistencies into Constraint Solvers

This article presents a generic scheme for adding strong local consistencies to the set of features of constraint solvers, which is notably applicable to event-based constraint solvers. We encapsulate a subset of constraints into a global constraint. This approach allows a solver to use different levels of consistency for different subsets of constraints in the same model. Moreover, we show how strong consistencies can be applied with different kinds of constraints, including user-defined constraints. We experiment our technique with a coarse-grained algorithm for Max-RPC, called Max-RPCrm, and a variant of it, L-Max-RPCrm. Experiments confirm the interest of strong consistencies for Constraint Programming tools.