Improving bidirectional heuristic search by bounds propagation

Shahaf S. Shperberg, Ariel Felner, Nathan R. Sturtevant, Solomon E. Shimony, Avi Hayoun

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

8 Scopus citations

Abstract

Recent research on bidirectional search describes anomalies, or cases in which improved heuristics lead to more node expansions. Aiming to avoid such anomalies, this paper characterizes desirable properties for bidirectional search algorithms, and studies conditions for obtaining these properties. The characterization is based on a recently developed theory for bidirectional search, which has formulated conditions on pairs of nodes such that at least one node from every pair meeting these conditions must be expanded. Moreover, based on this must-expand-pairs theory, we introduce a method for enhancing heuristics by propagating lower bounds (lb-propagation) between frontiers. This lb-propagation can bestow the desirable properties on some existing algorithms (e.g., the MM family) while avoiding the above anomaly altogether. Empirical results show that lb-propagation reduces the number of node expansions in many cases.

Original languageEnglish
Title of host publicationProceedings of the 12th International Symposium on Combinatorial Search, SoCS 2019
EditorsPavel Surynek, William Yeoh
PublisherAAAI press
Pages106-114
Number of pages9
ISBN (Electronic)9781577358084
StatePublished - 1 Jan 2019
Event12th International Symposium on Combinatorial Search, SoCS 2019 - Napa, United States
Duration: 16 Jul 201917 Jul 2019

Publication series

NameProceedings of the 12th International Symposium on Combinatorial Search, SoCS 2019

Conference

Conference12th International Symposium on Combinatorial Search, SoCS 2019
Country/TerritoryUnited States
CityNapa
Period16/07/1917/07/19

ASJC Scopus subject areas

  • Computer Networks and Communications

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