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arXiv 2401.04553stat.MLcs.LG
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线性递归特征机可证明恢复低秩矩阵

Linear Recursive Feature Machines provably recover low-rank matrices

Harvard University(哈佛大学);Broad Institute of MIT and Harvard(布罗德研究所);Halıcıoğlu Data Science Institute, UC San Diego(加州大学圣迭戈分校哈勒西奥卢数据科学研究所);University of Washington(华盛顿大学)

Adityanarayanan Radhakrishnan, Mikhail Belkin, Dmitriy Drusvyatskiy

AI总结:

本研究为递归特征机(RFM)在过参数化问题中的降维机制提供了首个理论保证,证明线性RFM推广了IRLS算法,并提出一种无SVD且可扩展至数百万缺失条目的高效实现,在稀疏回归和低秩补全任务中优于标准IRLS和深度线性网络。

摘要:

机器学习中的一个基本问题是理解神经网络如何做出准确预测,同时似乎绕过了维数灾难。一种可能的解释是,神经网络的常见训练算法隐式地执行了降维——这一过程被称为特征学习。近期的研究提出,特征学习的效果可以从一种名为平均梯度外积(AGOP)的经典统计估计器中引出。作者提出了递归特征机(RFM)作为一种算法,通过交替执行以下两个步骤来显式地进行特征学习:(1)通过AGOP对特征向量进行重新加权;(2)在变换后的空间中学习预测函数。在本研究中,我们通过聚焦于稀疏线性回归和低秩矩阵恢复中出现的过参数化问题类别,为RFM如何执行降维开发了首个理论保证。具体而言,我们证明了局限于线性模型的RFM(lin-RFM)推广了被广泛研究的迭代重加权最小二乘(IRLS)算法。我们的结果阐明了神经网络中的特征学习与经典稀疏恢复算法之间的联系。此外,我们提供了lin-RFM的一种实现,该实现可扩展至具有数百万个缺失条目的矩阵。我们的实现比标准IRLS算法更快,因为它无需SVD(奇异值分解)。在稀疏线性回归和低秩矩阵补全任务中,它也优于深度线性网络。

英文摘要:

A fundamental problem in machine learning is to understand how neural networks make accurate predictions, while seemingly bypassing the curse of dimensionality. A possible explanation is that common training algorithms for neural networks implicitly perform dimensionality reduction - a process called feature learning. Recent work posited that the effects of feature learning can be elicited from a classical statistical estimator called the average gradient outer product (AGOP). The authors proposed Recursive Feature Machines (RFMs) as an algorithm that explicitly performs feature learning by alternating between (1) reweighting the feature vectors by the AGOP and (2) learning the prediction function in the transformed space. In this work, we develop the first theoretical guarantees for how RFM performs dimensionality reduction by focusing on the class of overparametrized problems arising in sparse linear regression and low-rank matrix recovery. Specifically, we show that RFM restricted to linear models (lin-RFM) generalizes the well-studied Iteratively Reweighted Least Squares (IRLS) algorithm. Our results shed light on the connection between feature learning in neural networks and classical sparse recovery algorithms. In addition, we provide an implementation of lin-RFM that scales to matrices with millions of missing entries. Our implementation is faster than the standard IRLS algorithm as it is SVD-free. It also outperforms deep linear networks for sparse linear regression and low-rank matrix completion.

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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