Be Like Water: Adaptive Floating Point for Machine Learning

In the pursuit of optimizing memory and compute density to accelerate machine learning applications, reduced precision training and inference has been an active area of research. While some approaches selectively apply low precision computations, this may require costly off-chip data transfers or mixed precision support. In this paper, we propose a novel numerical representation, Adaptive Floating Point (AFP), that dynamically adjusts to the characteristics of deep learning data. AFP requires no changes to the model topology, requires no additional training, and applies to all layers of DNN models. We evaluate AFP on a spectrum of representative models in computer vision and NLP, and show that our technique enables ultra-low precision inference of deep learning models while providing accuracy comparable to full precision inference. By dynamically adjusting to ML data, AFP increases memory density by 1.6x, 1.6x, and 3.2x and compute density by 4x, 1.3x, and 12x when compared to BFP, BFloat16, and FP32.