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Abstract:This paper studies how adaptive randomized pivoting (ARP), recently introduced for matrix column subset selection, can be extended to tensors in the t-product framework. We propose two constructions. The first one, called ARP-T-CUR, applies matrix ARP independently to the frontal slices of the tensor in the Fourier domain. This gives a Fourier-slicewise CUR approximation and leads to a direct expected-error bound inherited from the matrix theory. The second construction, called T-ARP, selects common lateral and horizontal slices for the whole tensor. This produces a genuine tensor cross approximation in the t-product sense, but also introduces a new difficulty: the same pivot indices must be used across all Fourier slices. We make this coupling explicit and prove an expected-error bound under a frequency-alignment condition measuring how far the common tensor-level sampling rule is from the slice-wise ARP sampling rules. This condition recovers the usual $r+1$-type factor when the leverage-score distributions are aligned across frequencies. We also discuss the resulting tensor cross approximation and its connection with t-DEIM. Numerical experiments on synthetic tensors, images, and videos illustrate the behavior of the proposed methods and show the benefit of common-index tensor sampling over standard tensor cross baselines.

Submission history

From: Valentin Leplat [view email]
[v1] Thu, 25 Jun 2026 07:18:49 UTC (4,155 KB)