Specific Filtering Algorithms for Over-Constrained Problems

In recent years, many constraint-specific filtering algorithms have been introduced. Such algorithms use the semantics of the constraint to perform filtering more efficiently than a generic algorithm. The usefulness of such methods has been widely proven for solving constraint satisfaction problems. In this paper, we extend this concept to over-constrained problems by associating specific filtering algorithms with constraints that may be violated. We present a paradigm that places no restrictions on the constraint filtering algorithms used. We illustrate our method with a complete study of the All-different constraint.