The Need for Different Domain-independent Heuristics

PRODIGY’s planning algorithm uses domain-independent search heuristics. In this paper, we support our that there is no ~ search heuristic that performs more efficiently than others for all problems or in all domains. The paper presents three diIFerent domaln-independent search heuristics of increasing complexity. We run PRODIGY with these heuristics in a series of artificial domms (introduced in (Barrett & Weld 1994)) where in fact one of the heuristics performs more eBicient]y than the others. However, we introduce an additional simple domain where the apparently worst heuristic outperforms the other two. The results we obtained in our empirical experiments lead to the main conclusion of this paper: p]~-ming algorithms need to use different search heuristics in difereat domains. We coac]ude the paper by advocating the need to learn the correspondence between particular domain characteristics and specific search heuristics for planning efficiently in complex domains.