vix.ing · top · new · best · stats · spec

Randomized biorthogonalization through a two-sided Gram-Schmidt process

2025/09/04 by Grigori, Laura, Piccinini, Lorenzo, Simunec, Igor · 1 citation
#65F25 (Primary) 65F15 (Secondary) #FOS: Mathematics #Numerical Analysis (math.NA)

paper · doi:10.48550/arxiv.2509.04386

Abstract

We propose and analyze a randomized two-sided Gram-Schmidt process for the biorthogonalization of two given matrices X, Y ∈ℝn× m. The algorithm aims to find two matrices Q, P ∈ℝn× m such that \rm range(X) = \rm range(Q), \rm range(Y) = \rm range(P) and (ΩQ)T ΩP = I, where Ω∈ℝs × n is a sketching matrix satisfying an oblivious subspace ε-embedding property; in other words, the biorthogonality condition on the columns of Q and P is replaced by an equivalent condition on their sketches. This randomized approach is computationally less expensive than the classical two-sided Gram-Schmidt process, has better numerical stability, and the condition number of the computed bases Q, P is often smaller than in the deterministic case. Several different implementations of the randomized algorithm are analyzed and compared numerically. The randomized two-sided Gram-Schmidt process is applied to the nonsymmetric Lancozs algorithm for the approximation of eigenvalues and both left and right eigenvectors.

Citations

Cited by

Related