Exploiting parallelism in the ME calculus

We present some parallelization techniques for the Model Evolution (ME) calculus, an instantiation-based calculus that lifts the DPLL procedure to first-order clause logic. Specifically, we consider a restriction of ME to the EPR fragment of clause logic for which the calculus is a decision procedure. The main operations in ME’s proof procedures, namely clause instantiation and candidate literal generation, offer opportunities for MapReducestyle parallelization. This term/clause-level parallelization is largely orthogonal to the sort of search-level parallelization performed by portfolio approaches. We describe a hybrid parallel proof procedure for the restricted calculus that exploits parallelism at both levels to synergistic effect. The calculus and the proof procedure have been implemented in a new solver for EPR formulas. Our initial experimental results show that our term/clauselevel parallelization alone is effective in reducing runtime and can be combined with a portfolio-based approach to maximize performance.