Improved Analysis of Khatri-Rao Random Projections and Applications

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Hauptverfasser: Saibaba, Arvind K., Verma, Bhisham Dev, Ballard, Grey
Format: Preprint
Veröffentlicht: 2025
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author Saibaba, Arvind K.
Verma, Bhisham Dev
Ballard, Grey
author_facet Saibaba, Arvind K.
Verma, Bhisham Dev
Ballard, Grey
contents Randomization has emerged as a powerful set of tools for large-scale matrix and tensor decompositions. Randomized algorithms involve computing sketches with random matrices. A prevalent approach is to take the random matrix as a standard Gaussian random matrix, for which the theory is well developed. However, this approach has the drawback that the cost of generating and multiplying by the random matrix can be prohibitively expensive. Khatri-Rao random projections (KRPs), obtained by sketching with Khatri-Rao products of random matrices, offer a viable alternative and are much cheaper to generate. However, the theoretical guarantees of using KRPs are much more pessimistic compared to their accuracy observed in practice. We attempt to close this gap by obtaining improved analysis of the use of KRPs in matrix and tensor low-rank decompositions. We propose and analyze a new algorithm for low-rank approximations of block-structured matrices (e.g., block Hankel) using KRPs. We also show how to accelerate tensor computations in the Tucker format using KRPs and give theoretical guarantees of the resulting low-rank approximations. Numerical experiments on synthetic and real-world tensors show the computational benefits of the proposed methods.
format Preprint
id arxiv_https___arxiv_org_abs_2507_23207
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Improved Analysis of Khatri-Rao Random Projections and Applications
Saibaba, Arvind K.
Verma, Bhisham Dev
Ballard, Grey
Numerical Analysis
Randomization has emerged as a powerful set of tools for large-scale matrix and tensor decompositions. Randomized algorithms involve computing sketches with random matrices. A prevalent approach is to take the random matrix as a standard Gaussian random matrix, for which the theory is well developed. However, this approach has the drawback that the cost of generating and multiplying by the random matrix can be prohibitively expensive. Khatri-Rao random projections (KRPs), obtained by sketching with Khatri-Rao products of random matrices, offer a viable alternative and are much cheaper to generate. However, the theoretical guarantees of using KRPs are much more pessimistic compared to their accuracy observed in practice. We attempt to close this gap by obtaining improved analysis of the use of KRPs in matrix and tensor low-rank decompositions. We propose and analyze a new algorithm for low-rank approximations of block-structured matrices (e.g., block Hankel) using KRPs. We also show how to accelerate tensor computations in the Tucker format using KRPs and give theoretical guarantees of the resulting low-rank approximations. Numerical experiments on synthetic and real-world tensors show the computational benefits of the proposed methods.
title Improved Analysis of Khatri-Rao Random Projections and Applications
topic Numerical Analysis
url https://arxiv.org/abs/2507.23207