Dynamic Polynomial Watchdog Encoding for Solving Weighted MaxSAT

Authors: Tobias Paxian, Sven Reimer and Bernd Becker

Paper Information

Title:Dynamic Polynomial Watchdog Encoding for Solving Weighted MaxSAT
Authors:Tobias Paxian, Sven Reimer and Bernd Becker
Proceedings:SAT Proceedings
Editors: Christoph M. Wintersteiger and Olaf Beyersdorff
Keywords:MaxSAT, Totalizer, Cardinality Constraint, Weighted MaxSAT

ABSTRACT. In this paper we present a novel cardinality constraint encoding for solving the weighted MaxSAT problem with iterative SAT-based methods based on the Polynomial Watchdog (PW) CNF encoding for Pseudo-Boolean (PB) constraints. The watchdog of the PW encoding indicates whether the bound of the PB constraint holds. In our approach, we lift this static watchdog concept to a dynamic one allowing an incremental convergence to the optimal result. Consequently, we formulate and implement a SAT-based algorithm for our new Dynamic Polynomial Watchdog (DPW) encoding which can be applied for solving the MaxSAT problem. Furthermore, we introduce three fundamental optimizations of the PW encoding also suited for the original version leading to a significantly less encoding size.

Our experimental results show that our encoding and algorithm is competitive with state-of-the-art encodings as utilized in QMaxSAT (3rd place in last MaxSAT Evaluation 2017). Our encoding dominates two of the QMaxSAT encodings, and at the same time is able to solve unique instances. We integrated our new encoding into QMaxSAT and adapt the heuristic to choose between the only remaining encoding of QMaxSAT and our approach. This combined version solves 19 (4%) more instances in overall 30% less run time on the benchmark set of the MaxSAT Evaluation 2017. However, for the instances solved by both solvers our encoding is 2X faster than all employed encodings of QMaxSAT used in the evaluation.

Talk:Jul 09 14:30 (Session 49F: MaxSAT)