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Approximate counting in SMT and value estimation for probabilistic programs. (English) Zbl 1420.68194

Baier, Christel (ed.) et al., Tools and algorithms for the construction and analysis of systems. 21st international conference, TACAS 2015, held as part of the European joint conferences on theory and practice of software, ETAPS 2015, London, UK, April 11–18, 2015. Proceedings. Berlin: Springer. Lect. Notes Comput. Sci. 9035, 320-334 (2015).
Summary: #SMT, or model counting for logical theories, is a well-known hard problem that generalizes such tasks as counting the number of satisfying assignments to a Boolean formula and computing the volume of a polytope. In the realm of satisfiability modulo theories (SMT) there is a growing need for model counting solvers, coming from several application domains (quantitative information flow, static analysis of probabilistic programs). In this paper, we show a reduction from an approximate version of #SMT to SMT.
We focus on the theories of integer arithmetic and linear real arithmetic. We propose model counting algorithms that provide approximate solutions with formal bounds on the approximation error. They run in polynomial time and make a polynomial number of queries to the SMT solver for the underlying theory, exploiting “for free” the sophisticated heuristics implemented within modern SMT solvers. We have implemented the algorithms and used them to solve a value estimation problem for a model of loop-free probabilistic programs with nondeterminism.
For the entire collection see [Zbl 1360.68006].

MSC:

68T20 Problem solving in the context of artificial intelligence (heuristics, search strategies, etc.)
68N30 Mathematical aspects of software engineering (specification, verification, metrics, requirements, etc.)