An Incremental Hierarchical Constraint Solver

This paper presents an incremental method to solve hierarchies of constraints over finite domains, which borrows techniques developed in intelligent backtracking, and finds locally-predicate-better solutions. A prototype implementation of this method, IHCS, was written in C and can be integrated with different programming environments. In particular, with Prolog producing an instance of an HCLP language. Possible applications of IHCS are briefly illustrated with a time-tabling and a set covering problem. Because of its portability and incremental nature, IHCS is well suited for reactive systems, allowing the interactive introduction and removal of preferred constraints