Effectiveness of pre- and inprocessing for CDCL-based SAT solving
This work addresses the practical problem of optimizing SAT solver performance for real-world and combinatorial instances, but it is incremental as it evaluates existing techniques rather than introducing new ones.
The paper investigates the efficiency of pre- and inprocessing techniques for simplifying CNF formulas in CDCL-based SAT solvers, finding that certain combinations yield desirable speedups while others should be avoided.
Applying pre- and inprocessing techniques to simplify CNF formulas both before and during search can considerably improve the performance of modern SAT solvers. These algorithms mostly aim at reducing the number of clauses, literals, and variables in the formula. However, to be worthwhile, it is necessary that their additional runtime does not exceed the runtime saved during the subsequent SAT solver execution. In this paper we investigate the efficiency and the practicability of selected simplification algorithms for CDCL-based SAT solving. We first analyze them by means of their expected impact on the CNF formula and SAT solving at all. While testing them on real-world and combinatorial SAT instances, we show which techniques and combinations of them yield a desirable speedup and which ones should be avoided.