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 * ''sublists'' (list of [[Doc/OpenList|OpenList]]): sub open lists
 * ''boost'' (int): boost value for sub-open-lists that are restricted to preferred operator nodes
'''Preferred operators:''' Preferred operators are only taken from sub-open-lists that do not consider the evaluated state a dead end.

'''Dead ends:''' A state is considered a dead end if either all alternated open lists agree that it is a dead end or at least one reliable open list considers it a dead end. A state is never inserted into a sub-open-list that considers it a dead end.

'''Note:''' The treatment of dead ends is different from the one described in the [[http://tr.informatik.uni-freiburg.de/reports/report258/report00258.ps.gz|technical report]] "The More, the Merrier: Combining [[Doc/Heuristic|Heuristic]] Estimators for Satisficing Planning (Extended Version)" (Department of Computer Science at Freiburg University, No. 258, 2010)
 * ''sublists'' (list of [[Doc/OpenList|OpenList]]): open lists between which this one alternates
 * ''boost'' (int): boost value for contained open lists that are restricted to preferred successors
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 * ''state_uniform_selection'' (bool): When removing an entry, we select a non-dominated bucket and return its oldest entry. If this option is false, we select uniformly from the non-dominated buckets; if the option is true, we weight the buckets with the number of entries.   * ''state_uniform_selection'' (bool): When removing an entry, we select a non-dominated bucket and return its oldest entry. If this option is false, we select uniformly from the non-dominated buckets; if the option is true, we weight the buckets with the number of entries.
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Bucket-based open list implementation that uses a single evaluator Bucket-based open list implementation that uses a single evaluator. Ties are broken in FIFO order.

Alternation open list

alternates between several open lists.

alt(sublists, boost=0)
  • sublists (list of OpenList): open lists between which this one alternates

  • boost (int): boost value for contained open lists that are restricted to preferred successors

Pareto open list

Selects one of the Pareto-optimal (regarding the sub-evaluators) entries for removal.

pareto(evals, pref_only=false, state_uniform_selection=false)
  • evals (list of ScalarEvaluator): scalar evaluators

  • pref_only (bool): insert only nodes generated by preferred operators

  • state_uniform_selection (bool): When removing an entry, we select a non-dominated bucket and return its oldest entry. If this option is false, we select uniformly from the non-dominated buckets; if the option is true, we weight the buckets with the number of entries.

Standard open list

Standard open list that uses a single evaluator

single(eval, pref_only=false)
  • eval (ScalarEvaluator): scalar evaluator

  • pref_only (bool): insert only nodes generated by preferred operators

Bucket-based open list

Bucket-based open list implementation that uses a single evaluator. Ties are broken in FIFO order.

single_buckets(eval, pref_only=false)
  • eval (ScalarEvaluator): scalar evaluator

  • pref_only (bool): insert only nodes generated by preferred operators

Tie-breaking open list

tiebreaking(evals, pref_only=false, unsafe_pruning=true)
  • evals (list of ScalarEvaluator): scalar evaluators

  • pref_only (bool): insert only nodes generated by preferred operators

  • unsafe_pruning (bool): allow unsafe pruning when the main evaluator regards a state a dead end

FastDownward: Doc/OpenList (last edited 2019-03-08 12:08:33 by XmlRpcBot)