Beyond Red-Black Planning: Limited-Memory State Variables
نویسندگان
چکیده
Red-black planning delete-relaxes only some of the state variables. This is coarse-grained in that, for each variable, it either remembers all past values (red), or remembers only the most recent one (black). We herein introduce limited-memory state variables, that remember a subset of their most recent values. It turns out that planning is still PSPACE-complete even when the memory is large enough to store all but a single value. Nevertheless, limited memory can be used to substantially broaden a known tractable fragment of red-black planning, yielding better heuristic functions in some domains.
منابع مشابه
Red-Black Planning: A New Tractability Analysis and Heuristic Function
Red-black planning is a recent approach to partial delete relaxation, where red variables take the relaxed semantics (accumulating their values), while black variables take the regular semantics. Practical heuristic functions can be generated from tractable sub-classes of red-black planning. Prior work has identified such sub-classes based on the black causal graph, i. e., the projection of the...
متن کاملWho Said We Need to Relax All Variables?
Despite its success in both satisficing and optimal planning, the delete relaxation has significant pitfalls in many important classes of planning domains, and it has been a challenge from the outset to devise heuristics that take some deletes into account. We herein devise an elegant and simple method for doing just that. In the context of finite-domain state variables, we define red variables...
متن کاملRed-black planning: A new systematic approach to partial delete relaxation
a r t i c l e i n f o a b s t r a c t To date, delete relaxation underlies some of the most effective heuristics for deterministic planning. Despite its success, however, delete relaxation has significant pitfalls in many important classes of planning domains, and it has been a challenge from the outset to devise heuristics that take some deletes into account. We herein devise an elegant and si...
متن کاملRed-Black Relaxed Plan Heuristics
Despite its success, the delete relaxation has significant pitfalls. Recent work has devised the red-black planning framework, where red variables take the relaxed semantics (accumulating their values), while black variables take the regular semantics. Provided the red variables are chosen so that redblack plan generation is tractable, one can generate such a plan for every search state, and ta...
متن کاملPartial Delete Relaxation, Unchained: On Intractable Red-Black Planning and Its Applications
Partial delete relaxation methods, like red-black planning, are extremely powerful, allowing in principle to force relaxed plans to behave like real plans in the limit. Alas, that power has so far been chained down by the computational overhead of the use as heuristic functions, necessitating to compute a relaxed plan on every search state. For red-black planning in particular, this has entaile...
متن کامل