MaxRPC algorithms based on bitwise operations

Abstract

Max Restricted Path Consistency (maxRPC) is a promising domain filtering consistency for binary constraints. In existing algorithms, the process of searching for PC-witnesses requires most constraint checks. And the computing speed of this process significantly affects the efficiency of the whole algorithm. In this paper, we propose a new method based on bitwise operations to speed up the computations of this process. Two algorithms maxRPCbit and maxRPCbi+rm utilizing this new method are proposed. Both algorithms and their light versions outperform the best ones among existing algorithms by a large margin. Significantly, our experiments, which compare the search algorithms applying light maxRPC with the one maintaining arc consistency, demonstrate that maxRPC is a much more promising filtering technique than what we thought. © 2011 Springer-Verlag.