Towards Formal Evaluation and Verification of Probabilistic Design

In the nanometer regime of integrated circuit fabrication, device variability imposes serious challenges to the design and manufacturing of reliable systems. A new computation paradigm of approximate and probabilistic design has been proposed recently to accept design imperfection as a resource for certain applications. Despite recent intensive study on approximate design, probabilistic design receives relatively few attentions. This paper provides a general formulation for the evaluation and verification of probabilistic design. We establish their connection to stochastic Boolean satisfiability (SSAT), (weighted) model counting and probabilistic model checking. Moreover, a novel SSAT solver based on binary decision diagram (BDD) is proposed, and a comparative experimental study is performed to contrast the strengths and weaknesses of different solutions. The proposed BDD-based SSAT solver obtains the best scalability among all techniques in our experiments. We also compare the BDD-based SSAT solver to a prior method based on Bayesian network modeling. Experimental results show that our method outperforms the prior method by orders of magnitude in both runtime and memory usage. Our work can be an essential step towards automated synthesis of probabilistic design.