UniPTS: A Unified Framework for Proficient Post-Training Sparsity
Authors: Jingjing Xie, Yuxin Zhang, Mingbao Lin, Liujuan Cao, Rongrong Ji

Post-training Sparsity (PTS) is a recently emerged avenue that chases efficient network sparsity with limited data in need. Existing PTS methods however undergo significant performance degradation compared with traditional methods that retrain the sparse networks via the whole dataset especially at high sparsity ratios. In this paper we attempt to reconcile this disparity by transposing three cardinal factors that profoundly alter the performance of conventional sparsity into the context of PTS. Our endeavors particularly comprise (1) A base-decayed sparsity objective that promotes efficient knowledge transferring from dense network to the sparse counterpart. (2) A reducing-regrowing search algorithm designed to ascertain the optimal sparsity distribution while circumventing overfitting to the small calibration set in PTS. (3) The employment of dynamic sparse training predicated on the preceding aspects aimed at comprehensively optimizing the sparsity structure while ensuring training stability. Our proposed framework termed UniPTS is validated to be much superior to existing PTS methods across extensive benchmarks. As an illustration it amplifies the performance of POT a recently proposed recipe from 3.9% to 68.6% when pruning ResNet-50 at 90% sparsity ratio on ImageNet.