Solving non-deterministic planning problems with pattern database heuristics

Abstract

Non-determinism arises naturally in many real-world applications of action planning. Strong plans for this type of problems can be found using A* search guided by an appropriate heuristic function. Most domain-independent heuristics considered in this context so far are based on the idea of ignoring delete lists and do not properly take the non-determinism into account. Therefore, we investigate the applicability of pattern database (PDB) heuristics to non-deterministic planning. PDB heuristics have emerged as rather informative in a deterministic context. Our empirical results suggest that PDB heuristics can also perform reasonably well in non-deterministic planning. Additionally, we present a generalization of the pattern additivity criterion known from classical planning to the non-deterministic setting. © 2009 Springer Berlin Heidelberg.