SAS+ Planning as Satisfiability

Abstract

Planning as satisfiability is a principal approach to planning with many eminent advantages. The existing planning as satisfiability techniques usually use encodings compiled from STRIPS. We introduce a novel SAT encoding scheme (SASE) based on the SAS+ formalism. The new scheme exploits the structural information in SAS+, resulting in an encoding that is both more compact and efficient for planning. We prove the correctness of the new encoding by establishing an isomorphism between the solution plans of SASE and that of STRIPS based encodings. We further analyze the transition variables newly introduced in SASE to explain why it accommodates modern SAT solving algorithms and improves performance. We give empirical statistical results to support our analysis. We also develop a number of techniques to further reduce the encoding size of SASE, and conduct experimental studies to show the strength of each individual technique. Finally, we report extensive experimental results to demonstrate significant improvements of SASE over the state-of-the-art STRIPS based encoding schemes in terms of both time and memory efficiency

Property Directed Reachability for Automated Planning

“…The concrete form of the formulas in the sequence is dictated by an encoding scheme (see, e.g., Kautz, McAllester, & Selman, 1996;Rintanen, Heljanko, & Niemelä, 2006;Huang, Chen, & Zhang, 2012). Most encoding schemes have a simple structure that can be captured by an STS S = (Σ, I, G, T ), from which the individual formulas F i are then obtained as…”

“…The validator VAL then complains about the resulting plans. Huang et al (2012). The particular implementation we used derives from the FreeLunch planning library (Balyo et al, 2012).…”

“…29. This choice ruled out systems like SatPlan (Kautz et al, 2006) or SASE (Huang et al, 2012) from the comparison, because they only optimize with respect to the parallel plan semantics. 30.…”

Underestimation vs. Overestimation in SAT-Based Planning

“…In this work we consider, respectively, PrecoSAT [1] and the SAT-MAX-PLAN encoding [18]. PrecoSAT was the winner of the Application Track of the 2009 SAT Competition 1 and has been successfully exploited in several SAT-based approaches for planning, e.g., [18,9,19].…”

Diseño e implementación de un planificador para un agente autónomo

“…En [60] se exploran distintas opciones para la traducción a SAT y se comparan sus resultados. Huang propone un conjunto de expresiones diferente [30], [31] pero partiendo del formalismo SAS+.…”