Analysis of eigenvalue clustering leads to optimal scaling in numerical radiative transfer

Fuente: arXiv
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Main Authors: Benedusi, Pietro, Riva, Simone, Belluzzi, Luca, Serra-Capizzano, Stefano
Format: Preprint
Published: 2026
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_version_ 1866914350445363200
author Benedusi, Pietro
Riva, Simone
Belluzzi, Luca
Serra-Capizzano, Stefano
author_facet Benedusi, Pietro
Riva, Simone
Belluzzi, Luca
Serra-Capizzano, Stefano
contents We consider a multidimensional polychromatic radiative transfer (RT) problem, accounting for scattering processes in a general form, i.e. anisotropic (dipole) scattering with partial frequency redistribution. Given a discrete ordinates discretization, we report the corresponding matrix structures, depending on model and discretization parameters. Despite the possibly dense nature of these matrices, the use of Krylov methods is effective (especially in the matrix-free context) and robust. We propose a theoretical analysis, using the spectral tools of the symbol theory, explaining why Krylov convergence is robust w.r.t. all the discretization parameters, even in the unpreconditioned case. In fact, the compactness of the continuous operators used in the modeling leads to zero-clustered dense matrix sequences plus identity, so that the clustering at the unity of the spectra is deduced. Numerical experiments confirm the theoretical results, which have a direct application, for example, in the simulation of radiative transfer in stellar atmospheres, a key problem in astrophysical research. In general, we demonstrate that optimal scaling with respect to RT discretization parameters is expected for Krylov solution strategies.
format Preprint
id arxiv_https___arxiv_org_abs_2602_21958
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Analysis of eigenvalue clustering leads to optimal scaling in numerical radiative transfer
Benedusi, Pietro
Riva, Simone
Belluzzi, Luca
Serra-Capizzano, Stefano
Numerical Analysis
Solar and Stellar Astrophysics
85A25 35P05 65F15 65F10 65R20
We consider a multidimensional polychromatic radiative transfer (RT) problem, accounting for scattering processes in a general form, i.e. anisotropic (dipole) scattering with partial frequency redistribution. Given a discrete ordinates discretization, we report the corresponding matrix structures, depending on model and discretization parameters. Despite the possibly dense nature of these matrices, the use of Krylov methods is effective (especially in the matrix-free context) and robust. We propose a theoretical analysis, using the spectral tools of the symbol theory, explaining why Krylov convergence is robust w.r.t. all the discretization parameters, even in the unpreconditioned case. In fact, the compactness of the continuous operators used in the modeling leads to zero-clustered dense matrix sequences plus identity, so that the clustering at the unity of the spectra is deduced. Numerical experiments confirm the theoretical results, which have a direct application, for example, in the simulation of radiative transfer in stellar atmospheres, a key problem in astrophysical research. In general, we demonstrate that optimal scaling with respect to RT discretization parameters is expected for Krylov solution strategies.
title Analysis of eigenvalue clustering leads to optimal scaling in numerical radiative transfer
topic Numerical Analysis
Solar and Stellar Astrophysics
85A25 35P05 65F15 65F10 65R20
url https://arxiv.org/abs/2602.21958