Stochastic Synthesis for Stochastic Computing

Stochastic computing (SC) is an emerging computing technique which offers higher computational density, and lower power over binary-encoded (BE) computation. Unlike BE computation, SC encodes values as probabilistic bitstreams which makes designing new circuits unintuitive. Existing techniques for synthesizing SC circuits are limited to specific classes of functions such as polynomial evaluation or constant scaling. In this paper, we propose using stochastic synthesis, which is originally a program synthesis technique, to automate the task of synthesizing new SC circuits. Our results show stochastic synthesis is more general than past techniques and can synthesize manually designed SC circuits as well as new ones such as an approximate square root unit.