Abstract

Abstract. Constraint satisfaction problems can be SAT-encoded in more than one way, and the choice of encoding can be as important as the choice of search algorithm. Theoretical results are few but experimental comparisons have been made between encodings, using both local and backtrack search algorithms. This paper compares local search performance on seven encodings of graph colouring benchmarks. Two of the encodings are new and one of them gives generally better results than known encodings. We also find better results than expected for two variants of the log encoding, and surprisingly poor results for the support encoding. 1

Citations

636	A machine program for theorem proving - Davis, Logemann, et al. - 1962
620	A New Method for Solving Hard Satisfiability Problems - Selman, Levesque, et al. - 1992
318	Noise strategies for improving local search - Selman, Kautz, et al. - 1994
113	Automatic SAT-compilation of planning problems - Ernst, Millstein - 1997
62	On the parallel complexity of discrete relaxation in constraint satisfaction networks - Kasif - 1990
29	SAT-encodings, search space structure, and local search performance - Hoos - 1999
28	P.W.: Solving nonboolean satisfiability problems with stochastic local search: A comparison of encodings - Frisch, Peugniez, et al. - 2005
25	Chaff: Engineering an Efficient SAT - Moskewicz, Madigan, et al. - 2001
17	adding more constraints makes a problem easier for hill-climbing algorithms: Analysing landscapes of csp’s - Why - 1997
14	S: SAT-variable complexity of hard combinatorial problems - Iwama, Miyazaki - 1994
14	Negative effects of modeling techniques on search performance - Prestwich - 2003
12	Lifted Search Engines for Satisfiability - Parkes - 1999
11	Another look at graph coloring via propositional satisfiability - Gelder
7	A SAT Approach to Query Optimization in Mediator Systems - Prestwich, Bressan - 2002
5	A SAT-Based Approach to Multiple Sequence Alignment - Prestwich, Higgins, et al. - 2003
4	and Putnam were already forward checking - Davis - 1996
3	Maintaining Arc-Consistency in Stochastic Local Search. Workshop on Techniques for Implementing Constraint Programming Systems - Prestwich - 2002
1	Density Condensation of Boolean Formulas - Hanatani, Horiyama, et al. - 2003