International Journal of Parallel Programming

, Volume 16, Issue 5, pp 341–364 | Cite as

Parallel consistent labeling algorithms

  • Ashok Samal
  • Tom Henderson


Mackworth and Freuder have analyzed the time complexity of several constraint satisfaction algorithms.(1) Mohr and Henderson have given new algorithms, AC-4 and PC-3, for arc and path consistency, respectively, and have shown that the arc consistency algorithm is optimal in time complexity and of the same order space complexity as the earlier algorithms.(2) In this paper, we give parallel algorithms for solving node and arc consistency. We show that any parallel algorithm for enforcing are consistency in the worst case must have O(na) sequential steps, wheren is number of nodes, anda is the number of labels per node. We give several parallel algorithms to do arc consistency. It is also shown that they all have optimal time complexity. The results of running the parallel algorithms on a BBN Butterfly multiprocessor are also presented.

Key Words

Arc consistency parallel algorithms constraint satisfaction inherent parallelism 


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Copyright information

© Plenum Publishing Corporation 1987

Authors and Affiliations

  • Ashok Samal
    • 1
  • Tom Henderson
  1. 1.Department of Computer ScienceUniversity of UtahSalt Lake City

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