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R39
Look-Ahead Value Ordering For Constraint Satisfaction Problems
Daniel Frost (frost@ics.uci.edu) & Rina Dechter (dechter@ics.uci.edu)

Abstract
Looking ahead during search is often useful when solving constraint satisfaction problems. Previous studies have shown that looking ahead helps by causing dead-ends to occur earlier in the search, and by providing information that is useful for dynamic variable ordering. In this paper, we show that another benefit of looking ahead is a useful domain value ordering heuristic, which we call look-ahead value ordering or LVO. LVO counts the number of times each value of the current variable con icts with some value of a future variable, and the value with the lowest number of con icts is chosen first. Our experiments show that look-ahead value ordering can be of substantial benefit, especially on hard constraint satisfaction problems.

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