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Main Authors: Tang, Ning, Peng, Zhichao
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2509.05001
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author Tang, Ning
Peng, Zhichao
author_facet Tang, Ning
Peng, Zhichao
contents The parametric radiative transfer equation (RTE) arises in multi-query applications, such as design optimization, inverse problems, and uncertainty quantification, which require solving the RTE multiple times for various parameters. Classical synthetic acceleration (SA) preconditioners are designed based on low-order approximations of a kinetic correction equation, e.g., its diffusion limit in diffusion synthetic acceleration (DSA). Despite their widespread success, these methods rely on empirical physical assumptions and do not leverage low-rank structures across parameters of the parametric problem. To address these limitations, our previous work introduced a reduced-order model (ROM) enhanced preconditioner called ROMSAD, which exploits low-rank structures across parameters and the original kinetic description of the correction equation. While ROMSAD improves overall efficiency compared with DSA, its efficiency reduces after the first iteration, because the construction of the underlying ROM ignores the preconditioner-dependence of the residual trajectory, leading to a mismatch between the offline and online residual trajectories. To overcome this issue, we introduce a trajectory-aware framework that iteratively constructs ROMs to eliminate the mismatch between offline and online residual trajectories. Numerical tests demonstrate superior efficiency over DSA, and substantial gains in both efficiency and robustness over ROMSAD. For a parametric lattice problem, trajectory-aware ROM preconditioners achieve rapid convergence within only $2$-$3$ iterations online.
format Preprint
id arxiv_https___arxiv_org_abs_2509_05001
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publishDate 2025
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spellingShingle Synthetic Acceleration Preconditioners for Parametric Radiative Transfer Equations based on Trajectory-Aware Reduced Order Models
Tang, Ning
Peng, Zhichao
Numerical Analysis
The parametric radiative transfer equation (RTE) arises in multi-query applications, such as design optimization, inverse problems, and uncertainty quantification, which require solving the RTE multiple times for various parameters. Classical synthetic acceleration (SA) preconditioners are designed based on low-order approximations of a kinetic correction equation, e.g., its diffusion limit in diffusion synthetic acceleration (DSA). Despite their widespread success, these methods rely on empirical physical assumptions and do not leverage low-rank structures across parameters of the parametric problem. To address these limitations, our previous work introduced a reduced-order model (ROM) enhanced preconditioner called ROMSAD, which exploits low-rank structures across parameters and the original kinetic description of the correction equation. While ROMSAD improves overall efficiency compared with DSA, its efficiency reduces after the first iteration, because the construction of the underlying ROM ignores the preconditioner-dependence of the residual trajectory, leading to a mismatch between the offline and online residual trajectories. To overcome this issue, we introduce a trajectory-aware framework that iteratively constructs ROMs to eliminate the mismatch between offline and online residual trajectories. Numerical tests demonstrate superior efficiency over DSA, and substantial gains in both efficiency and robustness over ROMSAD. For a parametric lattice problem, trajectory-aware ROM preconditioners achieve rapid convergence within only $2$-$3$ iterations online.
title Synthetic Acceleration Preconditioners for Parametric Radiative Transfer Equations based on Trajectory-Aware Reduced Order Models
topic Numerical Analysis
url https://arxiv.org/abs/2509.05001