There are two competing paradigms in successful SAT solvers: Conflict-driven clause learning (CDCL) and stochastic local search (SLS). CDCL uses systematic exploration of the search space and has the ability to learn new clauses. SLS examines the neighborhood of the current complete assignment. Unlike CDCL, it lacks the ability to learn from its mistakes. This work revolves around the question whether it is beneficial for SLS to add new clauses to the original formula. We experimentally demonstrate that clauses with a large number of correct literals w. r. t. a fixed solution are beneficial to the runtime of SLS. We call such clauses high-quality clauses.
Empirical evaluations show that short clauses learned by CDCL possess the high-quality attribute. We study several domains of randomly generated instances and deduce the most beneficial strategies to add high-quality clauses as a preprocessing step. The strategies are implemented in an SLS solver, and it is shown that this considerably improves the state-of-the-art on randomly generated instances. The results are statistically significant.
Circumspect descent prevails in solving random constraint satisfaction problems
Helsinki University of Technology(赫尔辛基理工大学);SICS Swedish Institute of Computer Science AB(瑞典计算机科学研究院);AlbaNova University Centre(阿尔巴诺瓦大学中心);KTH-Royal Institute of Technology(瑞典皇家理工学院);University of Helsinki(赫尔辛基大学);Helsinki Institute for Information Technology HIIT(赫尔辛基信息技术研究所)
Enhancing Local Search for MaxSAT with Deep Differentiation Clause Weighting
School of Computer Science, South China Normal University, Guangzhou, China(计算机科学学院,华南师范大学,广州,中国);School of Artificial Intelligence, South China Normal University, Foshan, China(人工智能学院,华南师范大学,佛山,中国)
Targeting Clause Type Distributions: a Picklock for Random Satisfiability Problems
Max Planck Institute for the Physics of Complex Systems(马克斯·普朗克复杂系统物理研究所);Institute of Theoretical Physics(理论物理研究所);Technische Universität Dresden(德累斯顿技术大学);Würzburg-Dresden Cluster of Excellence ctd.qmat(魏玛-德累斯顿卓越中心ctd.qmat)