A Brief Survey on Randomizer Design and Optimization for Efficient Stochastic Computing

Stochastic computing (SC) is a promising computing paradigm for circuit design in the post-Moore era. It encodes data through stochastic bit streams (SBSs) and employs a randomizer to generate them, where the randomizer converts binary-encoded variables into stochastic formats and can optionally provide some SBSs of constant values. Owing to this, the randomizer generally plays a critical role in determining the accuracy of SC circuits and occupies a significant portion of their hardware cost. Therefore, it is crucial to apply proper randomizers to enhance the overall performance and efficiency of SC circuits. However, recent SC circuit designs often suffer from complex randomizers to ensure high accuracy. To address this issue, several efficient designs and optimization methods of randomizers have been proposed. In this paper, we review the common designs, the optimization methods, and the efficient application of randomizers, while discussing current challenges and future directions. By providing a brief overview, this survey underscores the critical role of randomizer design and optimization for efficient SC.