arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2202.00834cs.LGcs.AIcs.DSstat.ML
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低秩神经网络的非线性建模方法

Nonlinear Initialization Methods for Low-Rank Neural Networks

Columbia University(哥伦比亚大学);Google(谷歌);Google Research(谷歌研究院)

Kiran Vodrahalli, Rakesh Shivanna, Maheswaran Sathiamoorthy, Sagar Jain, Ed H. Chi

摘要:

我们提出了一种新的低秩初始化框架,用于训练低秩深度神经网络-网络,其中权重参数由两个低秩矩阵的乘积重新参数化。最成功的现有方法,谱初始化,从满秩设置的初始化分布中抽取样本,然后通过奇异值分解用一对低秩初始化矩阵在Frobenius范数中最佳地近似满秩初始化参数。我们的方法的灵感来自于这样一种认识,即近似对应于每一层的函数比近似参数值更重要。我们可以证明,ReLU网络的这两种方法之间存在显著的差距,特别是当近似权重的期望秩降低时,或者当层输入的维度增加时(当网络宽度在维度上是超线性时,后一点成立)。在此过程中,我们提供了第一个可证明有效的算法来解决固定参数秩$r$的ReLU低秩近似问题-以前,即使对于秩$1$,也不知道该问题在计算上是否易于解决。我们还提供了一种实用的算法来解决这个问题,它不比现有的谱初始化方法更昂贵,并通过训练ResNet和EfficientNet模型来验证我们的理论(He et al.,2016; Tan & Le,2019)在ImageNet上(Russakovsky等人,2015年)。

英文摘要:

We propose a novel low-rank initialization framework for training low-rank deep neural networks -- networks where the weight parameters are re-parameterized by products of two low-rank matrices. The most successful prior existing approach, spectral initialization, draws a sample from the initialization distribution for the full-rank setting and then optimally approximates the full-rank initialization parameters in the Frobenius norm with a pair of low-rank initialization matrices via singular value decomposition. Our method is inspired by the insight that approximating the function corresponding to each layer is more important than approximating the parameter values. We provably demonstrate that there is a significant gap between these two approaches for ReLU networks, particularly as the desired rank of the approximating weights decreases, or as the dimension of the inputs to the layer increases (the latter point holds when the network width is super-linear in dimension). Along the way, we provide the first provably efficient algorithm for solving the ReLU low-rank approximation problem for fixed parameter rank $r$ -- previously, it was unknown that the problem was computationally tractable to solve even for rank $1$. We also provide a practical algorithm to solve this problem which is no more expensive than the existing spectral initialization approach, and validate our theory by training ResNet and EfficientNet models (He et al., 2016; Tan & Le, 2019) on ImageNet (Russakovsky et al., 2015).

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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