Abstract
Most complete SAT/ASP solvers are based on DPLL. One of the constraint propagation methods is the so-called lookahead, which has been somewhat controversial, due to its high overhead. In this paper, we show characterizations of the problems for which lookahead is ineffective, and demonstrate, experimentally, that for problems that lie in the phase transition regions, search efficiency can be improved significantly by lookahead. This understanding leads to the proposal of a mechanism called adaptive lookahead, which decides when lookahead should be invoked dynamically upon learned information. Our experiments show that adaptive lookahead adapts well to different situations where lookahead may or may not be beneficial.
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Liu, G., You, JH. (2007). On the Effectiveness of Looking Ahead in Search for Answer Sets. In: Baral, C., Brewka, G., Schlipf, J. (eds) Logic Programming and Nonmonotonic Reasoning. LPNMR 2007. Lecture Notes in Computer Science(), vol 4483. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-72200-7_30
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DOI: https://doi.org/10.1007/978-3-540-72200-7_30
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-72199-4
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