The SAT Solver C-SAT2

C-SAT2 is a SAT solver that accepts formulas in DIMACS CNF format. It is a complete solver based on the DPLL algorithm and optimized for industrial problems. The solver is an enhancement of our earlier circuit-based SAT solver CSAT [4]. In this enhancement, in addition to various techniques of original development in C-SAT, we also borrow ideas from CNF-based solvers such as zChaff [5] and Berkmin [3], and employ additional heuristics. In recent years, researchers have tried to develop better heuristics to enhance SAT solver efficiency, by speeding up the Boolean Constraint Propagation (BCP) procedure or finding a better decision ordering (or both). Also restart [2, 3], conflict-clause removal [3] and equivalence reasoning [1, 4] techniques have been proven very useful for hard cases. In the following, we will describe in detail the techniques used in C-SAT2.