Title
Sublinear Randomized Algorithms for Skeleton Decompositions.
Abstract
A skeleton decomposition of a matrix A is any factorization of the form A:(C)ZA(R):, where A:(C) comprises columns of A, and A(R): comprises rows of A. In this paper, we investigate the conditions under which random sampling of C and R results in accurate skeleton decompositions. When the singular vectors (or more generally the generating vectors) are incoherent, we show that a simple algorithm returns an accurate skeleton in sublinear O(l(3)) time from l similar or equal to k log n rows and columns drawn uniformly at random, with an approximation error of the form O(n/l sigma(k)) where sigma(k) is the kth singular value of A. We discuss the crucial role that regularization plays in forming the middle matrix U as a pseudoinverse of the restriction A(RC) of A to rows in R and columns in C. The proof methods enable the analysis of two alternative sublinear-time algorithms, based on the rank-revealing QR decomposition, which allows us to tighten the number of rows and/or columns to k with error bound proportional to sigma(k).
Year
DOI
Venue
2011
10.1137/110852310
SIAM JOURNAL ON MATRIX ANALYSIS AND APPLICATIONS
Keywords
DocType
Volume
skeleton,column subset selection,low-rank approximations,CUR,interpolative decomposition,Nystrom method
Journal
34
Issue
ISSN
Citations 
3
0895-4798
2
PageRank 
References 
Authors
0.35
15
2
Name
Order
Citations
PageRank
Jiawei Chiu130.73
Laurent Demanet275057.81