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Dynamic variable ordering in CSPs

  • Constraint Satisfaction Problems 2
  • Conference paper
  • First Online:
Principles and Practice of Constraint Programming — CP '95 (CP 1995)

Part of the book series: Lecture Notes in Computer Science ((LNCS,volume 976))

Abstract

We investigate the dynamic variable ordering (DVO) technique commonly used in conjunction with tree-search algorithms for solving constraint satisfaction problems. We first provide an implementation methodology for adding DVO to an arbitrary tree-search algorithm. Our methodology is applicable to a wide range of algorithms including those that maintain complicated information about the search history, like backmarking. We then investigate the popular reordering heuristic of next instantiating the variable with the minimum remaining values (MRV). We prove some interesting theorems about the MRV heuristic which demonstrate that if one wants to use the MRV heuristic one should use it with forward checking. Finally, we investigate the empirical performance of 12 different algorithms with and without DVO. Our experiments and theoretical results demonstrate that forward checking equipped with dynamic variable ordering is a very good algorithm for solving CSPs.

This research was supported by the Canadian Government through their IRIS project and NSERC programs.

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Author information

Authors and Affiliations

  1. Dept. of Computer Science, University of Waterloo, N2L 3G1, Waterloo, Ontario, Canada

    Fahiem Bacchus

  2. NN Financial, 1 Concorde Gate, M3C 3N6, Toronto, Ontario, Canada

    Paul van Run

Authors
  1. Fahiem Bacchus
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  2. Paul van Run
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Editor information

Ugo Montanari Francesca Rossi

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© 1995 Springer-Verlag Berlin Heidelberg

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Bacchus, F., van Run, P. (1995). Dynamic variable ordering in CSPs. In: Montanari, U., Rossi, F. (eds) Principles and Practice of Constraint Programming — CP '95. CP 1995. Lecture Notes in Computer Science, vol 976. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-60299-2_16

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  • DOI: https://doi.org/10.1007/3-540-60299-2_16

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  • Publisher Name: Springer, Berlin, Heidelberg

  • Print ISBN: 978-3-540-60299-6

  • Online ISBN: 978-3-540-44788-7

  • eBook Packages: Springer Book Archive

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