Multivalued action languages with constraints in CLP(FD)

Abstract

Action description languages, such asand ℬ (Gelfond and Lifschitz,Electronic Transactions on Artificial Intelligence, 1998, vol. 2, pp. 193—210), are expressive instruments introduced for formalizing planning domains and planning problem instances. The paper starts by proposing a methodology to encode an action language (with conditional effects and static causal laws), a slight variation of ℬ, usingConstraint Logic Programming over Finite Domains. The approach is then generalized to raise the use of constraints to the level of the action language itself. A prototype implementation has been developed, and the preliminary results are presented and discussed.

The RANTANPLAN planner: system description

“…Among the few works dealing with planning with resources are (Hoffmann, 2003;Kautz and Walser, 1999;Gerevini et al, 2008;Hoffmann et al, 2007). There have also been some works using constraint and logic programming (Dovier et al, 2010;Barták and Toropila, 2010). However, the advances in satisfiability modulo theories (SMT) (Barrett et al, 2009) in the last years make worth considering this alternative.…”

A Tabled Prolog Program for Solving Sokoban

“…The semantics of an Action Description Language in presence of static causal laws becomes complex [12,8] and is related to the notion of Answer Set [11]. As shown in detail in [7] B programs can be either -interpreted using constraint (logic) programming, or -automatically translated in Answer Set Programming and then solved using an ASP solver.…”

“…The BPSolver program is based on the dynamic programming approach and uses mode-directed tabling [18] to store subproblems and their answers. The program was built after failed attempts to use CLP(FD) and the planning languages B [12] and BMV [8] for the problem (see Section 6). The BPSolver program is very simple (only a few lines of code) but quite efficient.…”

Perspectives on Logic-Based Approaches for Reasoning about Actions and Change

“…Specifically, the target of the encoding is a constraint logic program over finite domains (CLP(FD)). The model presented here is an evolution of the pioneering work described in [10], with several modifications aimed at enhancing performance. As for the ASP encoding, we are interested in computing plans with N action occurrences, relating a sequence of N + 1 states s 0 , .…”

“…[5,10]) conjunction and disjunction constraints are implemented using the built-in CLP(FD) predicate minimum and maximum, respectively. Moreover, constraints (3) and (4) regarding four variables, are dealt with the combinatorial constraint table (only six 4-tuples are candidate solutions).…”