claspfolio2: Advances in Algorithm Selection for Answer Set Programming

Abstract

AbstractBuilding on the award-winning, portfolio-based ASP solverclaspfolio, we presentclaspfolio2, a modular and open solver architecture that integrates several different portfolio-based algorithm selection approaches and techniques. Theclaspfolio2 solver framework supports various feature generators, solver selection approaches, solver portfolios, as well as solver-schedule-based pre-solving techniques. The default configuration ofclaspfolio2 relies on a light-weight version of the ASP solverclaspto generate static and dynamic instance features. The flexible open design ofclaspfolio2 is a distinguishing factor even beyond ASP. As such, it provides a unique framework for comparing and combining existing portfolio-based algorithm selection approaches and techniques in a single, unified framework. Taking advantage of this, we conducted an extensive experimental study to assess the impact of different feature sets, selection approaches and base solver portfolios. In addition to gaining substantial insights into the utility of the various approaches and techniques, we identified a default configuration ofclaspfolio2 that achieves substantial performance gains not only overclasp's default configuration and the earlier version ofclaspfolio, but also over manually tuned configurations ofclasp.