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arXiv 2302.14772cs.CVcs.LG
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PA和DA:联合采样路径和数据以实现一致的NAS

PA&DA: Jointly Sampling PAth and DAta for Consistent NAS

Institute of Computing Technology, Chinese Academy of Sciences(中国科学院计算技术研究所);School of Computer Science and Technology, University of Chinese Academy of Sciences(中国科学院大学计算机科学与技术学院);Kuaishou Technology(快手科技)

Shun Lu, Yu Hu, Longxing Yang, Zihao Sun, Jilin Mei, Jianchao Tan, Chengru Song

摘要:

基于权值共享机制,one-shot NAS方法训练一个超网,然后继承预先训练好的权值来评估子模型,大大降低了搜索成本。然而,一些工作已经指出,共享权重在训练期间遭受不同的梯度下降方向。我们进一步发现,在超网训练过程中会出现较大的梯度方差,从而降低了超网的排序一致性。为了缓解这个问题,我们建议通过联合优化PATh和DAta(PA&DA)的采样分布来显式地最小化超网训练的梯度方差。从理论上推导了梯度方差与采样分布之间的关系,揭示了最优采样概率与路径和训练数据的归一化梯度范数成正比。因此,我们使用归一化梯度范数作为路径和训练数据的重要性指标,并采用重要性采样策略进行超网训练。我们的方法只需要微不足道的计算成本优化路径和数据的采样分布,但实现了更低的梯度方差在超网训练和更好的泛化性能的超网,从而导致更一致的NAS。在不同的搜索空间中,我们与其他改进方法进行了全面的比较。实验结果表明,该方法具有更可靠的排序性能和更高的搜索精度,显示了该方法的有效性。代码可在https://github.com/ShunLu91/PA-DA上获得。

英文摘要:

Based on the weight-sharing mechanism, one-shot NAS methods train a supernet and then inherit the pre-trained weights to evaluate sub-models, largely reducing the search cost. However, several works have pointed out that the shared weights suffer from different gradient descent directions during training. And we further find that large gradient variance occurs during supernet training, which degrades the supernet ranking consistency. To mitigate this issue, we propose to explicitly minimize the gradient variance of the supernet training by jointly optimizing the sampling distributions of PAth and DAta (PA&DA). We theoretically derive the relationship between the gradient variance and the sampling distributions, and reveal that the optimal sampling probability is proportional to the normalized gradient norm of path and training data. Hence, we use the normalized gradient norm as the importance indicator for path and training data, and adopt an importance sampling strategy for the supernet training. Our method only requires negligible computation cost for optimizing the sampling distributions of path and data, but achieves lower gradient variance during supernet training and better generalization performance for the supernet, resulting in a more consistent NAS. We conduct comprehensive comparisons with other improved approaches in various search spaces. Results show that our method surpasses others with more reliable ranking performance and higher accuracy of searched architectures, showing the effectiveness of our method. Code is available at https://github.com/ShunLu91/PA-DA.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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