Automatic Selection of Tensor Decomposition for Compressing Convolutional Neural Networks A Case Study on VGG-type Networks

Tensor decomposition is one of the model reduction techniques for compressing deep neural networks. Existing methods use either Tucker decomposition (TD) or Canonical Polyadic decomposition (CPD) for model compression, but none of them tried to combine those two methods, owing to the complexity of choosing a proper decomposition method for each layer. In this paper, we adopted the automatic tuning technique to design an algorithm that can mix both tensor decomposition methods, called Mixed Tensor Decomposition (MTD). The goal is to achieve better compression ratio while keeping similar accuracy as the original models. We used VGG type networks for the case study since they are relatively heavy and computationally expensive. We first studied the relation of model accuracy and compression ratio for Tucker and CPD applying to convolution neural networks (CNN). Based on the studied results, we designed a strategy to select the most suitable decomposition method for each layer, and further fine-tunes the models to recover the accuracy. We have conducted experiments using VGG11 and VGG16 with CIFAR10 dataset, and compared MTD with other tensor decomposition algorithms. The results show that MTD can achieve compression ratio 32 × and 37 × for VGG11 and VGG16 respectively with less than 1% accuracy drops, which is much better than the state-of-the-art tensor decomposition algorithms for model compression.