Matrix Approximation and Projective Clustering via Iterative Sampling

We present two new results for the problem of approximating a given real m by n matrix A by a rank-k matrix D, where k < min{m, n}, so as to minimize ||A-D||_F^2. It is known that bysampling O(k/eps) rows of the matrix, one can find a low-rank approximation with additive error eps||A||_F^2. Our...

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Main Authors: Rademacher, Luis, Vempala, Santosh, Wang, Grant
Other Authors: Algorithms
Language:en_US
Published: 2005
Online Access:http://hdl.handle.net/1721.1/30530
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author Rademacher, Luis
Vempala, Santosh
Wang, Grant
author2 Algorithms
author_facet Algorithms
Rademacher, Luis
Vempala, Santosh
Wang, Grant
author_sort Rademacher, Luis
collection MIT
description We present two new results for the problem of approximating a given real m by n matrix A by a rank-k matrix D, where k < min{m, n}, so as to minimize ||A-D||_F^2. It is known that bysampling O(k/eps) rows of the matrix, one can find a low-rank approximation with additive error eps||A||_F^2. Our first result shows that with adaptive sampling in t rounds and O(k/eps) samples in each round, the additive error drops exponentially as eps^t; the computation time is nearly linear in the number of nonzero entries. This demonstrates that multiple passes can be highly beneficial for a natural (and widely studied) algorithmic problem. Our second result is that there exists a subset of O(k^2/eps) rows such that their span contains a rank-k approximation with multiplicative (1+eps) error (i.e., the sum of squares distance has a small \"core-set\" whose span determines a good approximation). This existence theorem leads to a PTAS for the following projective clustering probl! em: Given a set of points P in R^d, and integers k,j, find a set of j subspaces F_1,...,F_j, each of dimension at most k, that minimize \\sum_{p \\in P} min_i d(p,F_i)^2.
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spelling mit-1721.1/305302019-04-11T06:23:23Z Matrix Approximation and Projective Clustering via Iterative Sampling Rademacher, Luis Vempala, Santosh Wang, Grant Algorithms We present two new results for the problem of approximating a given real m by n matrix A by a rank-k matrix D, where k < min{m, n}, so as to minimize ||A-D||_F^2. It is known that bysampling O(k/eps) rows of the matrix, one can find a low-rank approximation with additive error eps||A||_F^2. Our first result shows that with adaptive sampling in t rounds and O(k/eps) samples in each round, the additive error drops exponentially as eps^t; the computation time is nearly linear in the number of nonzero entries. This demonstrates that multiple passes can be highly beneficial for a natural (and widely studied) algorithmic problem. Our second result is that there exists a subset of O(k^2/eps) rows such that their span contains a rank-k approximation with multiplicative (1+eps) error (i.e., the sum of squares distance has a small \"core-set\" whose span determines a good approximation). This existence theorem leads to a PTAS for the following projective clustering probl! em: Given a set of points P in R^d, and integers k,j, find a set of j subspaces F_1,...,F_j, each of dimension at most k, that minimize \\sum_{p \\in P} min_i d(p,F_i)^2. 2005-12-22T02:25:21Z 2005-12-22T02:25:21Z 2005-03-29 MIT-CSAIL-TR-2005-018 MIT-LCS-TR-983 http://hdl.handle.net/1721.1/30530 en_US Massachusetts Institute of Technology Computer Science and Artificial Intelligence Laboratory 19 p. 17195378 bytes 797052 bytes application/postscript application/pdf application/postscript application/pdf
spellingShingle Rademacher, Luis
Vempala, Santosh
Wang, Grant
Matrix Approximation and Projective Clustering via Iterative Sampling
title Matrix Approximation and Projective Clustering via Iterative Sampling
title_full Matrix Approximation and Projective Clustering via Iterative Sampling
title_fullStr Matrix Approximation and Projective Clustering via Iterative Sampling
title_full_unstemmed Matrix Approximation and Projective Clustering via Iterative Sampling
title_short Matrix Approximation and Projective Clustering via Iterative Sampling
title_sort matrix approximation and projective clustering via iterative sampling
url http://hdl.handle.net/1721.1/30530
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