Exploiting MaxSAT for Preference-Based Planning

In this paper, we explore the application of partial weighted MaxSAT techniques for preference-based planning (PBP). To this end, we develop a compact partial weighted MaxSAT encoding for PBP based on the SAS formalism. Our encoding extends a SAS based encoding for SAT-based planning, SASE, to allow for the specification of simple preferences. To the best of our knowledge, the SAS formalism has never been exploited in the context of PBP. Our MaxSATbased PBP planner, MSPLAN, significantly outperformed a STRIPS-based MaxSAT approach for PBP with respect to running time, solving more problems in a few cases. Interestingly, when compared to SGPlan5 and HPLAN-P, two stateof-the-art heuristic search planners for PBP, MSPLAN consistently generated plans with comparable quality, slightly outperforming at least one of these two planners in almost every case. For some problems, MSPLAN was competitive with HPLAN-P with respect to running time. Our results illustrate the effectiveness of our SASE based encoding and suggests that MaxSAT-based PBP is a promising area of research.