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Abscon 112 Toward more Robustness
| Citations: | 6 - 0 self |
BibTeX
@MISC{Lecoutre_abscon112,
author = {Christophe Lecoutre and Sebastien Tabary},
title = {Abscon 112 Toward more Robustness},
year = {}
}
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Abstract
Abstract. This paper describes the three main improvements made to the solver Abscon 109 [9]. The new version, Abscon 112, is able to automatically break some variable symmetries, infer allDifferent constraints from cliques of variables that are pair-wise irreflexive, and use an optimized version of the STR (Simple Tabular Reduction) technique initially introduced by J. Ullmann for table constraints. 1 From Local to Global Variable Symmetries In [10], we have proposed to automatically detect variable symmetries of CSP instances by computing for each constraint scope a partition exhibiting locally symmetrical variables. From this local information that can be obtained in polynomial time, we can build a so-called lsv-graph whose automorphisms correspond to (global) variable symmetries. Interestingly enough, our approach allows us to disregard the representation (extension, intension, global) of constraints. Besides, the size of the lsv-graph is linear wrt the number of constraints (and their arity). To break symmetries from the generators returned by a graph automorphism
Keyphrases
variable symmetry symmetrical variable main improvement new version global variable symmetry polynomial time csp instance automorphisms correspond alldifferent constraint simple tabular reduction table constraint solver abscon so-called lsv-graph graph automorphism local information optimized version
