Designing parallel PDR

SMTS: Distributed, Visualized Constraint Solving

“…SMTS is based on the parallelization tree formalism [9], a parallelization approach relying on recurrent aspects of constraint solving algorithms, and therefore designed to be general enough to suit many different domains. We prove that SMTS is general enough to parallelize both the SMT solver OpenSMT2 [8] and the software model checker Z3-Spacer [2,16], which is based on the IC3 algorithm. In particular, three high-level elements recurring in most efficient implementations of SMT and IC3 that SMTS exploits in order to improve solving performance are: (i) the use of heuristic assumptions for dividing the search-space (see e.g.…”

“…Instantiating parallelization trees on different domains requires domainspecific knowledge, in particular to properly define partitioning, portfolio and lemma sharing. In the following we provide an overview of the SMT and IC3 instantiations, and we refer the reader respectively to [17], and [16] for further details.…”

“…These are commonly used in combination with sharing of learned information. We have observed analytically for SMT [10] and in practical experiments for both SMT [17] and IC3 [16] that when used alone, both partitioning and algorithm portfolios have their own shortcomings and one often seems to perform well exactly when the other performs badly. The parallelization tree is a hybrid approach capable of exploiting the strengths of each parallel approach in such circumstances.…”

“…In particular, three high-level elements recurring in most efficient implementations of SMT and IC3 that SMTS exploits in order to improve solving performance are: (i) the use of heuristic assumptions for dividing the search-space (see e.g. [19] for SMT, and [16] for IC3), (ii) learning lemmas from the logical formula [18,7], and (iii) the use of restarts to guide the solver to a more relevant search space [15].…”

“…The seminal paper on the model-checking algorithm IC3 [3] already provides experimental evidence on the efficiency of parallelization. Parallelization of IC3 is further investigated in [6], and by the authors in [16] in the context of the parallelization tree formalism. This paper presents a new tool for developing, supervising, and interacting with parallel algorithms.…”