Layer-Wise Training to Create Efficient Convolutional Neural Networks

Recent large CNNs have delivered impressive performance but their storage requirement and computational cost limit a wide range of their applications in mobile devices and large-scale Internet industry. Works focusing on storage compression have led a great success. Recently how to reduce computational cost draws more attention. In this paper, we propose an algorithm to reduce computational cost, which is often solved by sparsification and matrix decomposition methods. Since the computation is dominated by the convolutional operations, we focus on the compression of convolutional layers. Unlike sparsification and matrix decomposition methods which usually derive from mathematics, we receive inspiration from transfer learning and biological neural networks. We transfer the knowledge in state-of-the-art large networks to compressed small ones, via layer-wise training. We replace the complex convolutional layers in large networks with more efficient modules and keep their outputs in each-layer consistent. Modules in the compressed small networks are more efficient, and their design draws on biological neural networks. For AlexNet model, we achieve 3.62× speedup, with 0.11% top-5 error rate increase. For VGG model, we achieve 5.67× speedup, with 0.43% top-5 error rate increase.