On the Role of Sequential Circuits in Stochastic Computing
Paishun Ting, John P. Hayes · 2017
Interest in stochastic computing (SC) has been growing due to the need for low-cost circuitry in areas like image processing and machine learning. While combinational stochastic circuits are relatively easy to design, their limitations such as having few implementable functions and inaccuracies due to correlation, call for sequential components and design methods. The theory underlying sequential stochastic circuits is not fully understood, however. Almost all existing sequential SC circuits fall into the up/down-counter-based (UCB) class. In this paper, we identify and investigate a new SC circuit class: shift-register-based (SRB). We focus on the properties of SRB circuits and demonstrate their central role in stochastic computing. This leads to an algorithm MOUSE for sequential design optimization. By exploiting sequential stochastic equivalence, MOUSE can reduce SRB circuit cost without compromising performance or accuracy.