A Randomized Parallel Algorithm for Planar Graph Isomorphism
We present a parallel randomized algorithm running on aCRCW PRAM, to determine whether two planar graphs are isomorphic, and if so to find the isomorphism. We assume that we have a tree of separators for each planar graph (which can be computed by known algorithms inO(log2n) time withn1+ϵprocessors,...
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| Published in: | Journal of algorithms Vol. 28; no. 2; pp. 290 - 314 |
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| Main Authors: | , |
| Format: | Journal Article |
| Language: | English |
| Published: |
San Diego, CA
Elsevier Inc
01.08.1998
Elsevier |
| Subjects: | |
| ISSN: | 0196-6774, 1090-2678 |
| Online Access: | Get full text |
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| Summary: | We present a parallel randomized algorithm running on aCRCW PRAM, to determine whether two planar graphs are isomorphic, and if so to find the isomorphism. We assume that we have a tree of separators for each planar graph (which can be computed by known algorithms inO(log2n) time withn1+ϵprocessors, for any ϵ>0). Ifnis the number of vertices, our algorithm takesO(log(n)) time with processors and with a probability of failure of 1/nat most. The algorithm needs 2·log(m)−log(n)+O(log(n)) random bits. The number of random bits can be decreased toO(log(n)) by increasing the number of processors ton3/2+ϵ, for any ϵ>0. Our parallel algorithm has significantly improved processor efficiency, compared to the previous logarithmic time parallel algorithm of Miller and Reif (Siam J. Comput.20(1991), 1128–1147), which requiresn4randomized processors orn5deterministic processors. |
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| ISSN: | 0196-6774 1090-2678 |
| DOI: | 10.1006/jagm.1998.0943 |