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An Approach to Parallel Unification Using Transputers

  • Conference paper
GWAI-89 13th German Workshop on Artificial Intelligence

Part of the book series: Informatik-Fachberichte ((2252,volume 216))

Abstract

This paper presents the implementation of a parallel unification algorithm on a star-connected transputer network. As a basic data structure directed acyclic graphs (dags) are used for the representation of the terms to be unified. The runtime consumption of the proposed algorithm is in the worst case of order 0(n/2), where n is the number of nodes in the dag. In the best case, however, the runtime is only of order O(log n).

The algorithm consists of two parts to be executed: the matching and the occur-check. It is the task of the first part, the matching, to calculate the most general subsitutions for the variables of the input terms. Infinite substitutions are detected by the subsequent occur-check. To gain high performance the stated methods exploit parallelism contained in both matching and occur-check.

For the actual implementation different network structures are considered. A star-connected network is proposed as most adequate to the problem, as deadlocks can be easily avoided and the communication is reduced to a minimum.

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Author information

Authors and Affiliations

  1. Institut für Informatik, Technische Universität München, Germany

    Jochen Hager & Martin Moser

Authors
  1. Jochen Hager
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  2. Martin Moser
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Editor information

Editors and Affiliations

  1. Computerlinguistik, Universität Bielefeld, Postfach 8640, D-4800, Bielefeld 1, Germany

    Dieter Metzing

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© 1989 Springer-Verlag Berlin Heidelberg

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Hager, J., Moser, M. (1989). An Approach to Parallel Unification Using Transputers. In: Metzing, D. (eds) GWAI-89 13th German Workshop on Artificial Intelligence. Informatik-Fachberichte, vol 216. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-75100-4_10

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  • DOI: https://doi.org/10.1007/978-3-642-75100-4_10

  • Publisher Name: Springer, Berlin, Heidelberg

  • Print ISBN: 978-3-540-51743-6

  • Online ISBN: 978-3-642-75100-4

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