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math.NA2026
A Superfast Direct Solver for 2D Type-II Inverse Nonuniform Discrete Fourier Transform Based on Hierarchically Semiseparable Matrices
Yingzhou Li, Jingyu Liu
Reconstructing images on Cartesian grids from nonuniform Fourier samples is a basic computational task in Fourier reconstruction methods for computed tomography. This paper propose…
math.NA2025
A Superfast Direct Solver for Type-III Inverse Nonuniform Discrete Fourier Transform
Yingzhou Li, Jingyu Liu
The nonuniform discrete Fourier transform (NUDFT) and its inverse are widely used in various fields of scientific computing. In this article, we propose a novel superfast direct in…
math.NA2025
Hierarchical Tucker Low-Rank Matrices: Construction and Matrix-Vector Multiplication
Yingzhou Li, Jingyu Liu
In this paper, a hierarchical Tucker low-rank (HTLR) matrix is proposed to approximate non-oscillatory kernel functions in linear complexity. The HTLR matrix is based on the hierar…