2014 ImprovingtheModifiedNyströmMeth

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Subject Headings: Symmetric Positive Semidefinite Matrix.

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Abstract

The Nystrom method is an efficient approach to enabling large-scale kernel methods. The Nystrom method generates a fast approximation to any large-scale symmetric positive semidefinite (SPSD) matrix using only a few columns of the SPSD matrix. However, since the Nystrom approximation is low-rank, when the spectrum of the SPSD matrix decays slowly, the Nystrom approximation is of low accuracy. In this paper, we propose a variant of the Nystrom method called the modified Nystrom by spectral shifting (SS-Nystrom). The SS-Nystrom method works well no matter whether the spectrum of SPSD matrix decays fast or slow. We prove that our SS-Nystrom has a much stronger error bound than the standard and modified Nystrom methods, and that SS-Nystrom can be even more accurate than the truncated SVD of the same scale in some cases. We also devise an algorithm such that the SS-Nystrom approximation can be computed nearly as efficient as the modified Nystrom approximation. Finally, our SS-Nystrom method demonstrates significant improvements over the standard and modified Nystrom methods on several real-world datasets.

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 AuthorvolumeDate ValuetitletypejournaltitleUrldoinoteyear
2014 ImprovingtheModifiedNyströmMethShusen Wang
Chao Zhang
Hui Qian
Zhihua Zhang
Improving the Modified Nyström Method Using Spectral Shifting10.1145/2623330.26236142014