Advertisement

Exploiting E.cient Control and Data Structures in Logic Programs

  • Rong Yang
  • Steve Gregory
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 2257)

Abstract

One of the distinguishing features of declarative languages is the separation of control and logic. Ideally, this allows us to improve the efficiency of an algorithm by changing only the control but not the logic. In this work, we investigate new control strategies and data structures in logic programs. Our main focus is on logic programs which contain dependent non-determinate computation.

We propose a newt ype of finite domain variables, which allow any kind of compound terms in their domain. A compound term in the domain may contain unbound variables which can also become domain variables, leading to nested domain variables.With nested domain variables, we can represent the Cartesian product of several domains as a tree structure. That is, disjunctive constraints stores can be constructed as a nested domain. The consistency of a nested domain can then be checked simultaneously by different parts of computations. Two forms of lookahead are used to perform the consistency checking: deep lookahead and shallow lookahead. It is hoped that, with our lookahead techniques and nested domains, many unnecessary or-branches can be pruned at an early stage. We have tested our ideas by an experimental implementation under SICStus Prolog, and obtained very encouraging results.

Keywords

logic programming constraints satisfaction sequence comparison 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    R. Bahgat, V. Santos Costa, and R. Yang. ARCH: A Parallel Execution Model that Minimises the Search Space of Logic Programs. Egyptian Computer Journal, 23(2), 1996.Google Scholar
  2. 2.
    I. Dutra. A Flexible Scheduler for Andorra-I. In A. Beaumont and G. Gupta, editors, Lecture Notes in Computer Science 569, Parallel Execution of Logic Programs, pages 70–82. Springer-Verlag, June 1991.Google Scholar
  3. 3.
    G. Gupta and D. H. D. Warren. An Interpreter for the Extended Andorra Model. Presented at ICLP’90 Workshop on Parallel Logic Programming, Eilat, Israel, June 1990.Google Scholar
  4. 4.
    P. V. Hentenryck, Y. Deville, and C.-M. Teng. A generic arc-consistency algorithm and its specialization. Artificial Intelligence, 57, 1992.Google Scholar
  5. 5.
    S. Janson and S. Haridi. Programming Paradigms of the Andorra Kernel Language. In Logic Programming: Proceedings of the International Logic Programming Symposium, pages 167–186. MIT Press, October 1991.Google Scholar
  6. 6.
    A. Mackworth and E. C. Freuder. The Complexity of Constraint Satisfaction Revisited. Artificial Intelligence, 59(1,2):57–62, 1993.CrossRefGoogle Scholar
  7. 7.
    A. K. Mackworth. Consistency in Networks of Relations. Artificial Intelligence, 8(1):99–118, 1977.zbMATHCrossRefMathSciNetGoogle Scholar
  8. 8.
    R. Mohr and T. C. Henderson. Arc and Path Consistency Revisited. Artificial Intelligence, 28:225–233, 1986.CrossRefGoogle Scholar
  9. 9.
    R. Moolenaar and B. Demoen. Hybrid Tree Search in the Andorra Model. In Proceedings of the 8th International Conference on Logic Programming, pages 110–123. MIT Press, June 1994.Google Scholar
  10. 10.
    D. Sano. and J. B. Kruskal, editors. Time Warps, String Edit and Macromolecules: the Theory and Practice of Sequence Comparision. CSLI Publications, Reissueed edition, 1999.Google Scholar
  11. 11.
    V. Santos Costa, D. H. D. Warren, and R. Yang. The Andorra-I Engine: A parallel implementation of the Basic Andorra model. In Logic Programming: Proceedings of the 8th International Conference. MIT Press, 1991.Google Scholar
  12. 12.
    V. Santos Costa, D. H. D. Warren, and R. Yang. The Andorra-I Preprocessor: Supporting full Prolog on the Basic Andorra model. In Logic Programming: Proceedings of the 8th International Conference. MIT Press, 1991.Google Scholar
  13. 14.
    P. Van Hentenryck. Constraint Satisfaction in Logic Programming. MIT Press, 1989.Google Scholar
  14. 15.
    D. H. D. Warren. The Extended Andorra Model with Implicit Control. Presented at ICLP’90 Workshop on Parallel Logic Programming, Eilat, Israel, June 1990.Google Scholar
  15. 16.
    D. H. D. Warren. Personal communication, October 2001.Google Scholar
  16. 17.
    R. Yang et al. Performance of the Compiler-based Andorra-I System. In Logic Programming: Proceedings of the 10th International Conference. MIT Press, 1993.Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2002

Authors and Affiliations

  • Rong Yang
    • 1
  • Steve Gregory
    • 2
  1. 1.School of Computer ScienceUniversity of the West of EnglandUK
  2. 2.Department of Computer ScienceUniversity of BristolUK

Personalised recommendations