2020/11/30 by Markus Hegland, Hegland, Markus, Frank deHoog +1
Engineering · Mathematics · #FOS: Mathematics #Numerical Analysis (math.NA) #Sparse and Compressive Sensing Techniques #Statistical and numerical algorithms #Tensor decomposition and applications
paper · pdf · doi:10.48550/arxiv.2011.14626
openalex publication_date 2020/11/30 · openalex created_date 2022/09/12 · openalex updated_date 2026/07/28
Positive semi-definite matrices commonly occur as normal matrices of least squares problems in statistics or as kernel matrices in machine learning and approximation theory. They are typically large and dense. Thus algorithms to solve systems with such a matrix can be very costly. A core idea to reduce computational complexity is to approximate the matrix by one with a low rank. The optimal and well understood choice is based on the eigenvalue decomposition of the matrix. Unfortunately, this is computationally very expensive. Cheaper methods are based on Gaussian elimination but they require pivoting. We will show how invariant matrix theory provides explicit error formulas for an averaged error based on volume sampling. The formula leads to ratios of elementary symmetric polynomials on the eigenvalues. We discuss some new an old bounds and include several examples where an expected error norm can be computed exactly.