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Related papers: ARGOT: Accelerated radiative transfer on grids usi…

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In this work, we introduce a fast numerical algorithm to solve the time-dependent radiative transport equation (RTE). Our method uses the integral formulation of RTE and applies the treecode algorithm to reduce the computational complexity…

Numerical Analysis · Mathematics 2020-01-29 Hongkai Zhao , Yimin Zhong

Under the word RAM model, we design three data structures that can be constructed in $O(n\sqrt{\lg n})$ time over $n$ points in an $n \times n$ grid. The first data structure is an $O(n\lg^{\epsilon} n)$-word structure supporting orthogonal…

Data Structures and Algorithms · Computer Science 2020-06-23 Younan Gao , Meng He , Yakov Nekrich

The proliferation of data has sparked significant interest in leveraging findings from one study to estimate treatment effects in a different target population without direct outcome observations. However, the transfer learning process is…

Methodology · Statistics 2025-05-15 Seok-Jin Kim , Hongjie Liu , Molei Liu , Kaizheng Wang

Diffusing Alpha-emitters Radiation Therapy (DaRT) is a new method for treating solid tumors using alpha particles. Unlike conventional radiotherapy, where the physical models for dose calculations are known and routinely used, for DaRT a…

Medical Physics · Physics 2021-11-09 Guy Heger , Lior Arazi

We introduce the radiative transfer postprocessing code Subsweep. The code is based on the method of transport sweeps, in which the exact solution to the scattering-less radiative transfer equation is computed in a single pass through the…

Instrumentation and Methods for Astrophysics · Physics 2024-12-03 Toni Peter , Joseph S. W. Lewis , Ralf S. Klessen , Simon C. O. Glover , Guido Kanschat

We present an ultrafast opacity calculator that we name HELIOS-K. It takes a line list as an input, computes the shape of each spectral line and provides an option for grouping an enormous number of lines into a manageable number of bins.…

Earth and Planetary Astrophysics · Physics 2015-08-19 Simon L. Grimm , Kevin Heng

An implicit method for the ohmic dissipation is proposed. The proposed method is based on the Crank-Nicolson method and exhibits second-order accuracy in time and space. The proposed method has been implemented in the SFUMATO adaptive mesh…

Instrumentation and Methods for Astrophysics · Physics 2015-05-19 Tomoaki Matsumoto

Purpose: To provide a fast computational method, based on the proximal graph solver (POGS) - a convex optimization solver using the alternating direction method of multipliers (ADMM), for calculating an optimal treatment plan in rotating…

Medical Physics · Physics 2018-02-07 Myung Cho , Xiaodong Wu , Hossein Dakhah , Jirong Yi , Ryan T. Flynn , Yusung Kim , Weiyu Xu

Diffusion planners have shown promise in handling long-horizon and sparse-reward tasks due to the non-autoregressive plan generation. However, their inherent stochastic risk of generating infeasible trajectories presents significant…

Machine Learning · Computer Science 2024-06-10 Lang Feng , Pengjie Gu , Bo An , Gang Pan

We have derived the radiative-transfer equation for a point source with a specified intensity and spectrum, originating in the early Universe between the epochs of annihilation and recombination, at redshifts $z_\s =10^8\div 10^4$. The…

Astrophysics · Physics 2009-11-11 D. I. Nagirner S. L. Kirusheva

We present a continuum radiative transfer model grid for fitting observed spectral energy distributions (SEDs) of massive protostars. The model grid is based on the paradigm of core accretion theory for massive star formation with…

Astrophysics of Galaxies · Physics 2018-01-31 Yichen Zhang , Jonathan C. Tan

We develop efficient and high-order accurate solvers for the Helmholtz equation on complex geometry. The schemes are based on the WaveHoltz algorithm which computes solutions of the Helmholtz equation by time-filtering solutions of the wave…

Numerical Analysis · Mathematics 2025-04-07 Daniel Appelo , Jeffrey W. Banks , William D. Henshaw , Donald W. Schwendeman

The treatment of radiative transfer with multiple radiation sources is a critical challenge in simulations of star formation and the interstellar medium. In this paper we present the novel TreeRay method for solving general radiative…

Instrumentation and Methods for Astrophysics · Physics 2021-06-30 Richard Wünsch , Stefanie Walch , František Dinnbier , Daniel Seifried , Sebastian Haid , Andre Klepitko , Anthony P. Whitworth , Jan Palouš

A serious concern for semi-analytical galaxy formation models, aiming to simulate multi-wavelength surveys and to thoroughly explore the model parameter space, is the extremely time consuming numerical solution of the radiative transfer of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Laura Silva , Fabio Fontanot , Gian Luigi Granato

To facilitate the study of black hole fueling, star formation, and feedback in galaxies, we outline a method for treating the radial forces on interstellar gas due to absorption of photons by dust grains. The method gives the correct…

Astrophysics of Galaxies · Physics 2015-06-04 G. S. Novak , J. P. Ostriker , L. Ciotti

Reconstructing the tree of life from molecular sequences is a fundamental problem in computational biology. Modern data sets often contain a large number of genes, which can complicate the reconstruction problem due to the fact that…

Probability · Mathematics 2017-07-21 Constantinos Daskalakis , Sebastien Roch

We present an updated version of SKIRT, a 3D Monte Carlo radiative transfer code developed to simulate dusty galaxies. The main novel characteristics of the SKIRT code are the use of a stellar foam to generate random positions, an efficient…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Maarten Baes , Joris Verstappen , Ilse De Looze , Jacopo Fritz , Waad Saftly , Edgardo Vidal Pérez , Marko Stalevski , Sander Valcke

New implicit and implicit-explicit time-stepping methods for the wave equation in second-order form are described with application to two and three-dimensional problems discretized on overset grids. The implicit schemes are single step,…

Numerical Analysis · Mathematics 2024-04-24 Allison M. Carson , Jeffrey W. Banks , William D. Henshaw , Donald W. Schwendeman

Decision tree optimization is fundamental to interpretable machine learning. The most popular approach is to greedily search for the best feature at every decision point, which is fast but provably suboptimal. Recent approaches find the…

Machine Learning · Computer Science 2025-11-19 Varun Babbar , Hayden McTavish , Cynthia Rudin , Margo Seltzer

Oblique Decision Tree (ODT) separates the feature space by linear projections, as opposed to the conventional Decision Tree (DT) that forces axis-parallel splits. ODT has been proven to have a stronger representation ability than DT, as it…

Machine Learning · Computer Science 2025-02-04 Shen-Huan Lyu , Yi-Xiao He , Yanyan Wang , Zhihao Qu , Bin Tang , Baoliu Ye