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Solutions to many partial differential equations satisfy certain bounds or constraints. For example, the density and pressure are positive for equations of fluid dynamics, and in the relativistic case the fluid velocity is upper bounded by…

Numerical Analysis · Mathematics 2021-11-09 Kailiang Wu , Chi-Wang Shu

We describe a family of recursive methods for the synthesis of qubit permutations on quantum computers with limited qubit connectivity. Two objectives are of importance: circuit size and depth. In each case we combine a scalable heuristic…

Quantum Physics · Physics 2023-08-25 Cynthia Chen , Bruno Schmitt , Helena Zhang , Lev S. Bishop , Ali Javadi-Abhari

For many years, channels of a color image have been processed individually, or the image has been converted to grayscale one with respect to color image processing. Pure quaternion representation of color images solves this issue as it…

Image and Video Processing · Electrical Eng. & Systems 2020-07-21 Alireza Parchami , Mojtaba Mahdavi

There has been growing interest in high-order tensor methods for nonconvex optimization, with adaptive regularization, as they possess better/optimal worst-case evaluation complexity globally and faster convergence asymptotically. These…

Optimization and Control · Mathematics 2025-01-17 Coralia Cartis , Wenqi Zhu

The quantum image segmentation algorithm is to divide a quantum image into several parts, but most of the existing algorithms use more quantum resource(qubit) or cannot process the complex image. In this paper, an improved two-threshold…

Quantum Physics · Physics 2024-04-30 Lu Wang , Zhiliang Deng , Wenjie Liu

Recently, Krukier et al. [Generalized skew-Hermitian triangular splitting iteration methods for saddle-point linear systems, Numer. Linear Algebra Appl. 21 (2014) 152-170] proposed an efficient generalized skew-Hermitian triangular…

Numerical Analysis · Mathematics 2014-02-25 Yan Dou , Ai-Li Yang , Yu-Jiang Wu

In this work, we tackle the problem of hyperspectral (HS) unmixing by departing from the usual linear model and focusing on a Linear-Quadratic (LQ) one. The proposed algorithm, referred to as Successive Nonnegative Projection Algorithm for…

Signal Processing · Electrical Eng. & Systems 2020-12-09 Christophe Kervazo , Nicolas Gillis , Nicolas Dobigeon

A fundamental challenge in multiparameter persistent homology is the absence of a complete and discrete invariant. To address this issue, we propose an enhanced framework that realizes a holistic understanding of a fully commutative…

Algebraic Topology · Mathematics 2023-11-14 Yasuaki Hiraoka , Ken Nakashima , Ippei Obayashi , Chenguang Xu

Among the major remaining challenges for single image super resolution (SISR) is the capacity to recover coherent images with global shapes and local details conforming to human vision system. Recent generative adversarial network (GAN)…

Image and Video Processing · Electrical Eng. & Systems 2021-01-26 Yuanzhuo Li , Yunan Zheng , Jie Chen , Zhenyu Xu , Yiguang Liu

Non-convex functional constrained optimization problems have gained substantial attention in machine learning and data science, addressing broad requirements that typically go beyond the often performance-centric objectives. An influential…

Optimization and Control · Mathematics 2025-10-29 Sang Bin Moon , Jong Gwang Kim , Ashish Chandra , Christopher Brinton , Abolfazl Hashemi

In the NISQ (Noisy intermediate-scale quantum) area, Quantum computers can be utilized for deep learning by treating variational quantum circuits as neural network models. This can be achieved by first encoding the input data onto quantum…

High Energy Physics - Phenomenology · Physics 2023-11-29 A. Hammad , Kyoungchul Kong , Myeonghun Park , Soyoung Shim

Integral equation methods for the solution of partial differential equations, when coupled with suitable fast algorithms, yield geometrically flexible, asymptotically optimal and well-conditioned schemes in either interior or exterior…

Numerical Analysis · Mathematics 2015-06-05 Andreas Klöckner , Alexander Barnett , Leslie Greengard , Michael O'Neil

Multi-shifted linear systems with non-Hermitian coefficient matrices arise in numerical solutions of time-dependent partial/fractional differential equations (PDEs/FDEs), in control theory, PageRank problems, and other research fields. We…

Numerical Analysis · Mathematics 2021-07-26 Xian-Ming Gu , Ting-Zhu Huang , Bruno Carpentieri , Akira Imakura , Ke Zhang , Lei Du

In this paper, we study structured quasi-Newton methods for optimization problems with orthogonality constraints. Note that the Riemannian Hessian of the objective function requires both the Euclidean Hessian and the Euclidean gradient. In…

Optimization and Control · Mathematics 2018-09-05 Jiang Hu , Bo Jiang , Lin Lin , Zaiwen Wen , Yaxiang Yuan

The class of non-commutative hypercomplex number systems (HNS) of 4-dimension, constructed by using of non-commutative Grassmann-Clifford procedure of doubling of 2-dimensional systems is investigated in the article and established here are…

Numerical Analysis · Computer Science 2014-12-30 Yakiv O. Kalinovsky , Yuliya E. Boyarinova , Alina S. Turenko , Yana V. Khitsko

We present a proximal augmented Lagrangian based solver for general convex quadratic programs (QPs), relying on semismooth Newton iterations with exact line search to solve the inner subproblems. The exact line search reduces in this case…

Optimization and Control · Mathematics 2020-04-02 Ben Hermans , Andreas Themelis , Panagiotis Patrinos

Variational quantum algorithms provide a direct, physics-based approach to protein structure prediction, but their accuracy is limited by the coarse resolution of the energy landscapes generated on current noisy devices. We propose a hybrid…

Emerging Technologies · Computer Science 2025-10-09 Yuqi Zhang , Yuxin Yang , Feixiong Chen , Cheng-Chang Lu , Nima Saeidi , Samuel L. Volchenboum , Junhan Zhao , Siwei Chen , Weiwen Jiang , Qiang Guan

We describe algorithm MINRES-QLP and its FORTRAN 90 implementation for solving symmetric or Hermitian linear systems or least-squares problems. If the system is singular, MINRES-QLP computes the unique minimum-length solution (also known as…

Mathematical Software · Computer Science 2015-03-30 Sou-Cheng T. Choi , Michael A. Saunders

To approximate solutions of complex nonlinear partial differential equations remains a computational challenge, especially for sets of equations relevant in industry, such as Euler or Navier-Stokes equations. Even the most sophisticated…

Quantum Physics · Physics 2026-03-25 Maximilian Mandelt Buxadé , Stefan Langer , Philipp Bekemeyer

Consider the problem of finding the maximal nonpositive solvent $\Phi$ of the quadratic matrix equation (QME) $X^2 + BX + C =0$ with $B$ being a nonsingular $M$-matrix and $C$ an $M$-matrix such that $B^{-1}C\ge 0$, and $B - C - I$ a…

Numerical Analysis · Mathematics 2022-02-15 Cairong Chen