Training deep neural networks for binary communication with the Whetstone method


The computational cost of deep neural networks presents challenges to broadly deploying these algorithms. Low-power and embedded neuromorphic processors offer potentially dramatic performance-per-watt improvements over traditional processors. However, programming these brain-inspired platforms generally requires platform-specific expertise. It is therefore difficult to achieve state-of-the-art performance on these platforms, limiting their applicability. Here we present Whetstone, a method to bridge this gap by converting deep neural networks to have discrete, binary communication. During the training process, the activation function at each layer is progressively sharpened towards a threshold activation, with limited loss in performance. Whetstone sharpened networks do not require a rate code or other spike-based coding scheme, thus producing networks comparable in timing and size to conventional artificial neural networks. We demonstrate Whetstone on a number of architectures and tasks such as image classification, autoencoders and semantic segmentation. Whetstone is currently implemented within the Keras wrapper for TensorFlow and is widely extendable.

A preprint version of the article is available at ArXiv.

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Fig. 1: Overview of the Whetstone process.
Fig. 2: Training a single network through the Whetstone process.
Fig. 3: How Whetstone training influences the performance of different network topologies and tasks.
Fig. 4: Whetstone training requires N-hot output encodings.
Fig. 5: Whetstone has the ability to sharpen diverse networks.

Data availability

All data used come from publicly available datasets: MNIST34, Fashion-MNIST35, CIFAR36 and COCO19. Whetstone is available at, licensed under the GPL.


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This work was supported by Sandia National Laboratories’ Laboratory Directed Research and Development (LDRD) Program under the Hardware Acceleration of Adaptive Neural Algorithms Grand Challenge project and the DOE Advanced Simulation and Computing program. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, a wholly owned subsidiary of Honeywell International, for the US Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

This Article describes objective technical results and analysis. Any subjective views or opinions that might be expressed in the paper do not necessarily represent the views of the US Department of Energy or the US Government.

Author information

All authors contributed to Whetstone algorithm theory and design. W.S. and R.D. implemented code and performed experiments. W.S., C.M.V., R.D. and J.B.A. analysed results. W.S., C.M.V. and J.B.A. wrote the manuscript.

Correspondence to William Severa or James B. Aimone.

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Severa, W., Vineyard, C.M., Dellana, R. et al. Training deep neural networks for binary communication with the Whetstone method. Nat Mach Intell 1, 86–94 (2019).

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