Randomized-Accelerated FEAST: A Hybrid Approach for Large-Scale Eigenvalue Problems

Fuente: arXiv
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Autor principal: Nadiger, Ayush
Formato: Preprint
Publicado: 2025
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author Nadiger, Ayush
author_facet Nadiger, Ayush
contents We present Randomized-Accelerated FEAST (RA-FEAST), a hybrid algorithm that combines contour-integration-based eigensolvers with randomized numerical linear algebra techniques for efficiently computing partial eigendecompositions of large-scale matrices arising in statistical applications. By incorporating randomized subspace initialization to enable aggressive quadrature reduction and truncated refinement iterations, our method achieves significant computational speedups (up to 38x on sparse graph Laplacian benchmarks at n = 8000) while maintaining high-accuracy approximations to the target eigenspace. We provide a probabilistic error bound for the randomized warmstart, a stability result for inexact FEAST iterations under general perturbations, and a simple complexity model characterizing the trade-off between initialization cost and solver speedup. Empirically, we demonstrate that RA-FEAST can be more than an order of magnitude faster than standard FEAST while preserving accuracy on sparse Laplacian problems representative of modern spectral methods in statistics.
format Preprint
id arxiv_https___arxiv_org_abs_2512_01257
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Randomized-Accelerated FEAST: A Hybrid Approach for Large-Scale Eigenvalue Problems
Nadiger, Ayush
Numerical Analysis
Computation
65F15, 65F50
G.1.3; G.3
We present Randomized-Accelerated FEAST (RA-FEAST), a hybrid algorithm that combines contour-integration-based eigensolvers with randomized numerical linear algebra techniques for efficiently computing partial eigendecompositions of large-scale matrices arising in statistical applications. By incorporating randomized subspace initialization to enable aggressive quadrature reduction and truncated refinement iterations, our method achieves significant computational speedups (up to 38x on sparse graph Laplacian benchmarks at n = 8000) while maintaining high-accuracy approximations to the target eigenspace. We provide a probabilistic error bound for the randomized warmstart, a stability result for inexact FEAST iterations under general perturbations, and a simple complexity model characterizing the trade-off between initialization cost and solver speedup. Empirically, we demonstrate that RA-FEAST can be more than an order of magnitude faster than standard FEAST while preserving accuracy on sparse Laplacian problems representative of modern spectral methods in statistics.
title Randomized-Accelerated FEAST: A Hybrid Approach for Large-Scale Eigenvalue Problems
topic Numerical Analysis
Computation
65F15, 65F50
G.1.3; G.3
url https://arxiv.org/abs/2512.01257