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Thermal Radiative Transfer (TRT) is the dominant energy transfer mechanism in high-energy density physics with applications in inertial confinement fusion and astrophysics. The stiff interactions between the material and radiation fields…

Computational Physics · Physics 2019-05-01 Hans Hammer , HyeongKae Park , Luis Chacon

There are many methods for finding a particular solution to a nonhomogeneous linear ordinary differential equation (ODE) with constant coefficients. The method of undetermined coefficients, Laplace transform method and differential operator…

General Mathematics · Mathematics 2021-03-08 Jozef Fecenko

Context. The numerical modeling of the generation and transfer of polarized radiation is a key task in solar and stellar physics research and has led to a relevant class of discrete problems that can be reframed as linear systems. In order…

Solar and Stellar Astrophysics · Physics 2021-12-08 Gioele Janett , Pietro Benedusi , Luca Belluzzi , Rolf Krause

This paper studies the shallow Ritz method for solving one-dimensional diffusion-reaction problems. The method is capable of improving the order of approximation for non-smooth problems. By following a similar approach to the one presented…

Numerical Analysis · Mathematics 2025-10-24 Zhiqiang Cai , Anastassia Doktorova , Robert D. Falgout , César Herrera

A new code for evaluation of light absorption and scattering by interstellar dust grains is presented. The radiative transfer problem is solved using ray-tracing algorithm in a self-consistent and highly efficient way. The code demonstrates…

Astrophysics · Physics 2007-05-23 D. Semionov , V. Vansevicius

Autograd-based software packages have recently renewed interest in image registration using homography and other geometric models by gradient descent and optimization, e.g., AirLab and DRMIME. In this work, we emphasize on using complex…

Computer Vision and Pattern Recognition · Computer Science 2020-07-28 Abhishek Nan , Matthew Tennant , Uriel Rubin , Nilanjan Ray

In this paper, we introduce a highly accurate and efficient numerical solver for the radial Kohn--Sham equation. The equation is discretized using a high-order finite element method, with its performance further improved by incorporating a…

Numerical Analysis · Mathematics 2024-11-08 Zheming Luo , Yang Kuang

We introduce \texttt{featom}, an open source code that implements a high-order finite element solver for the radial Schr\"odinger, Dirac, and Kohn-Sham equations. The formulation accommodates various mesh types, such as uniform or…

Biomedical optical imaging has a possibility of a comprehensive diagnosis of thyroid cancer in conjunction with ultrasound imaging. For improvement of the optical imaging, this study develops a higher order scheme for solving the…

Medical Physics · Physics 2016-03-15 Hiroyuki Fujii , Shinpei Okawa , Ken Nadamoto , Eiji Okada , Yukio Yamada , Yoko Hoshi , Masao Watanabe

We present a new method for the numerical solution of the radiative-transfer equation (RTE) in multidimensional scenarios commonly encountered in computational astrophysics. The method is based on the direct solution of the Boltzmann…

Computational Physics · Physics 2020-10-06 L. R. Weih , A. Gabbana , D. Simeoni , L. Rezzolla , S. Succi , R. Tripiccione

An exact arithmetic, memory efficient direct solution method for finite element method (FEM) computations is outlined. Unlike conventional black-box or low-rank direct solvers that are opaque to the underlying physical problem, the proposed…

Computational Engineering, Finance, and Science · Computer Science 2020-02-13 Javad Moshfegh , Marinos N. Vouvakis

Higher-order ODE solvers have become a standard tool for accelerating diffusion probabilistic model (DPM) sampling, motivating the widespread view that first-order methods are inherently slower and that increasing discretization order is…

Machine Learning · Statistics 2026-01-01 Yuchen Jiao , Na Li , Changxiao Cai , Gen Li

We proposed a novel dense line spectrum super-resolution algorithm, the DMRA, that leverages dynamical multi-resolution of atoms technique to address the limitation of traditional compressed sensing methods when handling dense point-source…

Signal Processing · Electrical Eng. & Systems 2024-09-04 Mingguang Han , Yi Zeng , Xiaoguang Li , Tiejun Li

For discrete spectrum of 1D second-order differential/difference operators (with or without potential (killing), with the maximal/minimal domain), a pair of unified dual criteria are presented in terms of two explicit measures and the…

Probability · Mathematics 2015-01-15 Mu-Fa Chen

Existing super-resolution methods of optical imaging hold a solid place as an application in natural sciences, but many new developments allow for beating the diffraction limit in a more subtle way. One of the recently explored strategies…

Quantum Physics · Physics 2022-02-08 Mateusz Mazelanik , Adam Leszczyński , Michał Parniak

A new stable computational method for non-homogeneous waveguide equation with a piecewise uniform structure along the main propagation direction is constructed, based on the modified Dirichlet-to-Neumann (DtN) map of each uniform segment.…

Numerical Analysis · Mathematics 2012-06-11 Yin Wang , Jinyang Huang

This paper studies the shallow Ritz method for solving the one-dimensional diffusion problem. It is shown that the shallow Ritz method improves the order of approximation dramatically for non-smooth problems. To realize this optimal or…

Numerical Analysis · Mathematics 2025-11-25 Zhiqiang Cai , Anastassia Doktorova , Robert D. Falgout , César Herrera

A robust and general solver for the radial Schr\"odinger, Dirac, and Kohn--Sham equations is presented. The formulation admits general potentials and meshes: uniform, exponential, or other defined by nodal distribution and derivative…

Atomic Physics · Physics 2015-06-11 Ondřej Čertík , John E. Pask , Jiří Vackář

We present a new numerical approach that is able to solve the multi-dimensional radiative transfer equations in all opacity regimes on a Lagrangian, unstructured network of characteristics based on a stochastic point process. Our method…

Astrophysics · Physics 2007-05-23 Jelle Ritzerveld , Vincent Icke , Erik-Jan Rijkhorst

The numerical solution of time-dependent radiative transfer problems is challenging, both, due to the high dimension as well as the anisotropic structure of the underlying integro-partial differential equation. In this paper we propose a…

Numerical Analysis · Mathematics 2015-12-04 Herbert Egger , Matthias Schlottbom