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ACE: And/or-parallel copying-based execution of logic programs

  • Gopal Gupta
  • M. Hermenegildo
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 569)

Abstract

The stack copying approach, as exemplified by the MUSE system, has been shown to be a quite successful alternative for representing multiple environments during or-parallel execution of logic programs. In this paper we present a novel execution model for parallel implementation of logic programs which is capable of exploiting both independent and-parallelism and or-parallelism in an efficient way and which combines the stack copying approach in the implementation of or-parallelism with proven techniques in the implementation of independent and-parallelism, such as those used in &-Prolog. The and parallelism is expressed via &-Prolog's conditional graph expressions. We show how all solutions to non-deterministic and-parallel goals are found without repetitions. This is done through recomputation as in Prolog (and &-Prolog), i.e., solutions of and-parallel goals are not shared. We also propose a scheme for the efficient management of the address space in a way that is compatible with the apparently incompatible requirements of both and- and or-parallelism. The resulting system retains the advantages of both purely or-parallel systems as well as purely and-parallel systems.

Keywords

And/Or-parallelism Prolog Stack copying Conditional Graph Expressions 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1991

Authors and Affiliations

  • Gopal Gupta
    • 1
  • M. Hermenegildo
    • 2
  1. 1.Dept. of Computer ScienceU. of BristolBristolUK
  2. 2.Facultad de InformáticaU. Madrid (UPM)MadridSpain

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