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arXiv 1410.6089math.NAcs.NA
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张量的低秩近似

Low-rank approximation of tensors

University of Illinois at Chicago(伊利诺伊大学芝加哥分校)

Shmuel Friedland, Venu Tammali

AI总结:

本文研究了张量的低秩近似问题,提出了一种新的牛顿方法用于求解最佳(r₁,…,r_d)近似,并比较了不同近似方法的数值性能。

摘要:

在许多应用中,如数据压缩、成像或基因组数据分析,近似给定张量为稀疏可表示的张量很重要。对于矩阵,即2-张量,可以通过奇异值分解获得最佳秩k近似。对于非常大的矩阵,使用SVD进行低秩近似在计算上不可行。在这种情况下,不同的近似方法可用。似乎CUR分解的变种最适用。对于d-模式张量T,d>2,许多奇异值分解的推广已被提出以获得低张量秩分解。最合适的近似似乎是最佳(r₁,…,r_d)近似,它最大化了T在U₁,…,U_d张量积子空间上的l₂范数。最常用的方法是交替最大化方法(AMM)。它通过在U_i子空间上最大化,同时保持其他子空间固定,并反复交替进行i=1,…,d的过程。通常,AMM会收敛到一个局部最佳近似。该近似是相应映射在格拉斯曼流形上的固定点。我们建议了一种牛顿方法来寻找相应的固定点。我们还讨论了张量的CUR近似方法的变种。本文的第一部分是对张量低秩近似的综述。本文的第二新部分是针对最佳(r₁,…,r_d)近似的新型牛顿方法。我们比较了不同近似方法的数值性能。

英文摘要:

In many applications such as data compression, imaging or genomic data analysis, it is important to approximate a given tensor by a tensor that is sparsely representable. For matrices, i.e. 2-tensors, such a representation can be obtained via the singular value decomposition, which allows to compute best rank k-approximations. For very big matrices a low rank approximation using SVD is not computationally feasible. In this case different approximations are available. It seems that variants of CUR decomposition are most suitable. For d-mode tensors T with d>2, many generalizations of the singular value decomposition have been proposed to obtain low tensor rank decompositions. The most appropriate approximation seems to be best (r_1,...,r_d)-approximation, which maximizes the l_2 norm of the projection of T on a tensor product of subspaces U_1,...,U_d, where U_i is an r_i-dimensional subspace. One of the most common method is the alternating maximization method (AMM). It is obtained by maximizing on one subspace U_i, while keeping all other fixed, and alternating the procedure repeatedly for i=1,...,d. Usually, AMM will converge to a local best approximation. This approximation is a fixed point of a corresponding map on Grassmannians. We suggest a Newton method for finding the corresponding fixed point. We also discuss variants of CUR-approximation method for tensors. The first part of the paper is a survey on low rank approximation of tensors. The second new part of this paper is a new Newton method for best $(r_1,...,r_d)$-approximation. We compare numerically different approximation methods.

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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