Fast Debugging of PRISM Models

Christian Dehnert, Nils Jansen, Ralf Wimmer, Erika Ábrahám, Joost-Pieter Katoen

Abstract: In addition to rigorously checking whether a system conforms to a specification, model checking can provide valuable feedback in the form of succinct and understandable counterexamples. In the context of probabilistic systems, path- and subsystem-based counterexamples at the state-space level can be of limited use in debugging. As many probabilistic systems are described in a guarded command language like the one used by the popular model checker Prism, a technique identifying a subset of critical commands has recently been proposed. Based on repeatedly solving MaxSat instances, our novel approach to computing a minimal critical command set achieves a speed-up of up to five orders of magnitude over the previously existing technique.