On a shrink-and-expand technique for symmetric block eigensolvers

Fuente: arXiv
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Autori principali: Liu, Yuqi, Ma, Yuxin, Shao, Meiyue
Natura: Preprint
Pubblicazione: 2024
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author Liu, Yuqi
Ma, Yuxin
Shao, Meiyue
author_facet Liu, Yuqi
Ma, Yuxin
Shao, Meiyue
contents In symmetric block eigenvalue algorithms, such as the subspace iteration algorithm and the locally optimal block preconditioned conjugate gradient (LOBPCG) algorithm, a large block size is often employed to achieve robustness and rapid convergence. However, using a large block size also increases the computational cost. Traditionally, the block size is typically reduced after convergence of some eigenpairs, known as deflation. In this work, we propose a non-deflation-based, more aggressive technique, where the block size is adjusted dynamically during the algorithm. This technique can be applied to a wide range of block eigensolvers, reducing computational cost without compromising convergence speed. We present three adaptive strategies for adjusting the block size, and apply them to four well-known eigensolvers as examples. Detailed theoretical analysis and numerical experiments are provided to illustrate the efficiency of the proposed technique. In practice, an overall acceleration of 20% to 30% is observed.
format Preprint
id arxiv_https___arxiv_org_abs_2409_05572
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On a shrink-and-expand technique for symmetric block eigensolvers
Liu, Yuqi
Ma, Yuxin
Shao, Meiyue
Numerical Analysis
65F10, 65F15, 65F50
In symmetric block eigenvalue algorithms, such as the subspace iteration algorithm and the locally optimal block preconditioned conjugate gradient (LOBPCG) algorithm, a large block size is often employed to achieve robustness and rapid convergence. However, using a large block size also increases the computational cost. Traditionally, the block size is typically reduced after convergence of some eigenpairs, known as deflation. In this work, we propose a non-deflation-based, more aggressive technique, where the block size is adjusted dynamically during the algorithm. This technique can be applied to a wide range of block eigensolvers, reducing computational cost without compromising convergence speed. We present three adaptive strategies for adjusting the block size, and apply them to four well-known eigensolvers as examples. Detailed theoretical analysis and numerical experiments are provided to illustrate the efficiency of the proposed technique. In practice, an overall acceleration of 20% to 30% is observed.
title On a shrink-and-expand technique for symmetric block eigensolvers
topic Numerical Analysis
65F10, 65F15, 65F50
url https://arxiv.org/abs/2409.05572