Path Sample-Analytic Gradient Estimators for Stochastic Binary Networks
This work addresses a specific bottleneck in training binary neural networks, offering incremental improvements for researchers and practitioners in efficient deep learning.
The authors tackled the problem of gradient estimation in stochastic binary networks, which is challenging due to piecewise constant responses, by proposing a new method combining sampling and analytic approximation that reduces variance with small bias, leading to more stable training and higher accuracy in deep convolutional models.
In neural networks with binary activations and or binary weights the training by gradient descent is complicated as the model has piecewise constant response. We consider stochastic binary networks, obtained by adding noises in front of activations. The expected model response becomes a smooth function of parameters, its gradient is well defined but it is challenging to estimate it accurately. We propose a new method for this estimation problem combining sampling and analytic approximation steps. The method has a significantly reduced variance at the price of a small bias which gives a very practical tradeoff in comparison with existing unbiased and biased estimators. We further show that one extra linearization step leads to a deep straight-through estimator previously known only as an ad-hoc heuristic. We experimentally show higher accuracy in gradient estimation and demonstrate a more stable and better performing training in deep convolutional models with both proposed methods.