Abstract
Various encodings have been proposed to convert Constraint Satisfaction Problems (CSP) into Boolean Satisfiability problems (SAT). Some of them use a logical variable for each element in each domain: among these very successful are the direct and the support encodings.
Other methods, such as the log-encoding, use a logarithmic number of logical variables to encode domains. However, they lack the propagation power of the direct and support encodings, so many SAT solvers perform poorly on log-encoded CSPs.
In this paper, we propose a new encoding, called log-support, that combines the log and support encodings. It has a logarithmic number of variables, and uses support clauses to improve propagation. We also extend the encoding using a Gray code. We provide experimental results on Job-Shop scheduling and randomly-generated problems.
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Gavanelli, M. (2007). The Log-Support Encoding of CSP into SAT. In: Bessière, C. (eds) Principles and Practice of Constraint Programming – CP 2007. CP 2007. Lecture Notes in Computer Science, vol 4741. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-74970-7_59
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DOI: https://doi.org/10.1007/978-3-540-74970-7_59
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