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Shift: A Zero FLOP, Zero Parameter Alternative to Spatial Convolutions [pdf] (arxiv.org)
5 points by stablemap on Nov 23, 2017 | hide | past | pdf | 1 comment on HN

In plain words: Instead of learning a sliding filter, it slides feature maps sideways by fixed amounts, then mixes channels with a one-pixel filter — no learned weights or math. Swapping 3x3 filters for these shifts raised accuracy on two common image-classification tests while cutting parameters by 60%.

Abstract · Shift: A Zero FLOP, Zero Parameter Alternative to Spatial Convolutions

Neural networks rely on convolutions to aggregate spatial information. However, spatial convolutions are expensive in terms of model size and computation, both of which grow quadratically with respect to kernel size. In this paper, we present a parameter-free, FLOP-free "shift" operation as an alternative to spatial convolutions. We fuse shifts and point-wise convolutions to construct end-to-end trainable shift-based modules, with a hyperparameter characterizing the tradeoff between accuracy and efficiency. To demonstrate the operation's efficacy, we replace ResNet's 3x3 convolutions with shift-based modules for improved CIFAR10 and CIFAR100 accuracy using 60% fewer parameters; we additionally demonstrate the operation's resilience to parameter reduction on ImageNet, outperforming ResNet family members. We finally show the shift operation's applicability across domains, achieving strong performance with fewer parameters on classification, face verification and style transfer.

Bichen Wu, Alvin Wan, Xiangyu Yue, Peter Jin, Sicheng Zhao, Noah Golmant, Amir Gholaminejad, Joseph Gonzalez, Kurt Keutzer
arXiv:1711.08141 · cs.CV · submitted Nov 22, 2017 · updated Dec 3, 2017
abstract · pdf · html · Source code will be released afterwards

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Been doing this for a while. Full convulation is only cool because real neurons do this. Shifting makes more sense