External Memory Bidirectional Search

This paper studies external memory bidirectional search. That is, how bidirectional search algorithms can run using external memory such as hard drives or solid state drives. While external memory algorithms have been broadly studied in unidirectional search, they have not been studied in the context of bidirectional search. We show that the primary bottleneck in bidirectional search is the question of solution detection - knowing when the two search frontiers have met. We propose a method of delayed solution detection that makes external bidirectional search more efficient. Experimental results show the effectiveness of the approach.

[1]  Tomas Rokicki,et al.  The Diameter of the Rubik's Cube Group Is Twenty , 2013, SIAM J. Discret. Math..

[2]  Richard E. Korf,et al.  Best-First Frontier Search with Delayed Duplicate Detection , 2004, AAAI.

[3]  Alexander Reinefeld,et al.  AIDA Asynchronous Parallel IDA , 2006 .

[4]  James B. H. Kwa,et al.  BS*: An Admissible Bidirectional Staged Heuristic Search Algorithm , 1989, Artif. Intell..

[5]  Eric A. Hansen,et al.  Structured Duplicate Detection in External-Memory Graph Search , 2004, AAAI.

[6]  Wheeler Ruml,et al.  Heuristic Search for Large Problems With Real Costs , 2011, AAAI.

[7]  Ira Sheldon Pohl,et al.  Bi-directional and heuristic search in path problems , 1969 .

[8]  Jonathan Schaeffer,et al.  Searching with Pattern Databases , 1996, Canadian Conference on AI.

[9]  Nathan R. Sturtevant,et al.  Minimizing Writes in Parallel External Memory Search , 2013, IJCAI.

[10]  Jussi Rintanen.  29th AAAI Conference on Artificial Intelligence (AAAI), Austin, Texas, 2015 , 2015, AAAI 2015.

[11]  Richard E. Korf,et al.  Finding Optimal Solutions to Rubik's Cube Using Pattern Databases , 1997, AAAI/IAAI.

[12]  Richard E. Korf,et al.  Limitations of Front-To-End Bidirectional Heuristic Search , 2015, AAAI.

[13]  Shamsul Arefin,et al.  A New Approach of Iterative Deepening Bi- Directional Heuristic Front-to-Front Algorithm (IDBHFFA) , 2010 .

[14]  Richard E. Korf,et al.  Frontier search , 2005, JACM.

[15]  Zhifu Zhang,et al.  Inconsistent heuristics in theory and practice , 2011, Artif. Intell..

[16]  Nathan R. Sturtevant,et al.  Bidirectional Search That Is Guaranteed to Meet in the Middle , 2016, AAAI.

[17]  T. A. J. Nicholson,et al.  Finding the Shortest Route between Two Points in a Network , 1966, Comput. J..