A General Framework for Reordering Agents Asynchronously in Distributed CSP

Reordering agents during search is an essential component of the efficiency of solving a distributed constraint satisfaction problem. Termination values have been recently proposed as a way to simulate the min-domain dynamic variable ordering heuristic. The use of termination values allows the greatest flexibility in reordering agents dynamically while keeping polynomial space. In this paper, we propose a general framework based on termination values for reordering agents asynchronously. The termination values are generalized to represent various heuristics other than min-domain. Our general framework is sound, complete, terminates and has a polynomial space complexity. We implemented several variable ordering heuristics that are well-known in centralized CSPs but could not until now be applied to the distributed setting. Our empirical study shows the significance of our framework compared to state-of-the-art asynchronous dynamic ordering algorithms for solving distributed CSP.