DHP: Differentiable Meta Pruning via HyperNetworks
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Network pruning has been the driving force for the efficient inference of neural networks and the alleviation of model storage and transmission burden. Traditional network pruning methods focus on the per-filter influence on the network accuracy by analyzing the filter distribution. With the advent of AutoML and neural architecture search (NAS), pruning has become topical with automatic mechanism and searching based architecture optimization. However, current automatic designs rely on either reinforcement learning or evolutionary algorithm, which often do not have a theoretical convergence guarantee or do not converge in a meaningful time limit. In this paper, we propose a differentiable pruning method via hypernetworks for automatic network pruning and layer-wise configuration optimization. A hypernetwork is designed to generate the weights of the backbone network. The input of the hypernetwork, namely, the latent vectors control the output channels of the layers of backbone network. By applying ℓ_1 sparsity regularization to the latent vectors and utilizing proximal gradient, sparse latent vectors can be obtained with removed zero elements. Thus, the corresponding elements of the hypernetwork outputs can also be removed, achieving the effect of network pruning. The latent vectors of all the layers are pruned together, resulting in an automatic layer configuration. Extensive experiments are conducted on various networks for image classification, single image super-resolution, and denoising. And the experimental results validate the proposed method.
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