A mixed precision LOBPCG algorithm

The locally optimal block preconditioned conjugate gradient (LOBPCG) algorithm is a popular approach for computing a few smallest eigenvalues and the corresponding eigenvectors of a large Hermitian positive definite matrix A . In this work, we propose a mixed precision variant of LOBPCG that uses a...

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Vydáno v:Numerical algorithms Ročník 94; číslo 4; s. 1653 - 1671
Hlavní autoři: Kressner, Daniel, Ma, Yuxin, Shao, Meiyue
Médium: Journal Article
Jazyk:angličtina
Vydáno: New York Springer US 01.12.2023
Springer Nature B.V
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ISSN:1017-1398, 1572-9265
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Shrnutí:The locally optimal block preconditioned conjugate gradient (LOBPCG) algorithm is a popular approach for computing a few smallest eigenvalues and the corresponding eigenvectors of a large Hermitian positive definite matrix A . In this work, we propose a mixed precision variant of LOBPCG that uses a (sparse) Cholesky factorization of A computed in lower precision as the preconditioner. To further enhance performance, a mixed precision orthogonalization strategy is proposed. To analyze the impact of reducing precision in the preconditioner on performance, we carry out a rounding error and convergence analysis of PINVIT, a simplified variant of LOBPCG. Our theoretical results predict and our numerical experiments confirm that the impact on convergence remains marginal. In practice, our mixed precision LOBPCG algorithm typically reduces the computation time by a factor of 1.4 – 2.0 on both CPUs and GPUs.
Bibliografie:ObjectType-Article-1
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ISSN:1017-1398
1572-9265
DOI:10.1007/s11075-023-01550-9