An outerplanar graph is a planar graph that can be imbedded in the plane in such a way that all vertices lie on the exterior face. An outerplanar graph is maximal if no edge can be added to the graph without violating the outerplanarity. In this paper, an optimal parallel algorithm is proposed on th
A Randomized Parallel Algorithm for Planar Graph Isomorphism
β Scribed by Hillel Gazit; John H Reif
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 223 KB
- Volume
- 28
- Category
- Article
- ISSN
- 0196-6774
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β¦ Synopsis
We present a parallel randomized algorithm running on a CRCW 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 Ε½ Ε½ 2 .
1 q β which can be computed by known algorithms in O log n time with n . processors, for any β ) 0 . If n is the number of vertices, our algorithm takes
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O log n time with P s O n ΠΈ log n processors and with a probability of Ε½ .
Ε½ . Ε½ . Ε½ Ε½ .. failure of 1rn at most. The algorithm needs 2 ΠΈ log m y log n q O log n ran-Ε½ Ε½ .. dom bits. The number of random bits can be decreased to O log n by increasing the number of processors to n 3r 2qβ , for any β ) 0. Our parallel algorithm has significantly improved processor efficiency, compared to the previous logarithmic Ε½ Ε½ . . time parallel algorithm of Miller and Reif Siam J. Comput. 20 1991 , 1128α1147 , which requires n 4 randomized processors or n 5 deterministic processors.
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