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Consistency Maintenance for ABT

  • Marius-Călin Silaghi
  • Djamila Sam-Haroud
  • Boi Faltings
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 2239)

Abstract

One of the most powerful techniques for solving centralized constraint satisfaction problems (CSPs) consists of maintaining local consistency during backtrack search (e.g. [11]). Yet, no work has been reported on such a combination in asynchronous settings1. The difficulty in this case is that, in the usual algorithms, the instantiation and consistency enforcement steps must alternate sequentially. When brought to a distributed setting, a similar approach forces the search algorithm to be synchronous in order to benefit from consistency maintenance. Asynchronism [24],[14] is highly desirable since it increases flexibility and parallelism, and makes the solving process robust against timing variations. One of the most well-known asynchronous search algorithms is Asynchronous Backtracking (ABT). This paper shows how an algorithm for maintaining consistency during distributed asynchronous search can be designed upon ABT. The proposed algorithm is complete and has polynomial-space complexity. Since the consistency propagation is optional, this algorithms generalizes forward checking as well as chronological backtracking. An additional advance over existing centralized algorithms is that it can exploit available backtracking-no goods for increasing the strength of the maintained consistency. The experimental evaluation shows that it can bring substantial gains in computational power compared with existing asynchronous algorithms.

Keywords

Constraint Satisfaction Constraint Satisfaction Problem Outgoing Link Local Consistency Redundant Constraint 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2001

Authors and Affiliations

  • Marius-Călin Silaghi
    • 1
  • Djamila Sam-Haroud
    • 1
  • Boi Faltings
    • 1
  1. 1.Swiss Federal Institute of Technology (EPFL)EPFLSwitzerland

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