Abstract
In this paper, we describe a SAT-based constraint solver named Sugar and its performance evaluation. Sugar can solve CSP (Constraint Satisfaction Problem), COP (Constraint Optimization Problem), and Max-CSP by encoding a given problem into a SAT problem and then solving the encoded SAT problem with an external efficient SAT solver (e.g. MiniSat). As for the SAT encoding, a new encoding method named order encoding is used, which is more efficient for various problems compared with the direct encoding and the support encoding which are widely used. This paper also describes the summary of the results at the 2008 Third International CSP/Max-CSP Solver Competitions. In the competitions, Sugar became the winner in four categories out of ten categories.
