论文标题
关于PB求解器的弱化策略
On Weakening Strategies for PB Solvers
论文作者
论文摘要
当前的伪树状求解器实施了切割平面证明系统的不同变体,以在冲突分析期间推断新约束。这些变体之一是广义分辨率,可以推断出强大的约束,但是在结合伪树状约束时,其生成的系数的增长遭受了损害。另一个变体在于使用弱分裂和分裂,这在实践中更有效,但可以推断出较弱的约束。在这两种情况下,都必须削弱造成冲突的约束。但是,到目前为止,尚未评估其对伪树状求解器性能的影响。在本文中,研究了针对此规则的新应用策略,旨在推断出较小系数的强大限制。我们在SAT4J中实现了它们,并观察到它们每个都可以改善求解器的运行时间。尽管没有一个在所有基准上的表现都比其他表现更好,但在冲突方面施加弱势的表现令人惊讶,而在冲突中局部削弱和分裂以及侧面总体上提供最佳结果的原因。
Current pseudo-Boolean solvers implement different variants of the cutting planes proof system to infer new constraints during conflict analysis. One of these variants is generalized resolution, which allows to infer strong constraints, but suffers from the growth of coefficients it generates while combining pseudo-Boolean constraints. Another variant consists in using weakening and division, which is more efficient in practice but may infer weaker constraints. In both cases, weakening is mandatory to derive conflicting constraints. However, its impact on the performance of pseudo-Boolean solvers has not been assessed so far. In this paper, new application strategies for this rule are studied, aiming to infer strong constraints with small coefficients. We implemented them in Sat4j and observed that each of them improves the runtime of the solver. While none of them performs better than the others on all benchmarks, applying weakening on the conflict side has surprising good performance, whereas applying partial weakening and division on both the conflict and the reason sides provides the best results overall.