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Main Authors: Christner, Brian, Chan, Jesse
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2507.14488
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author Christner, Brian
Chan, Jesse
author_facet Christner, Brian
Chan, Jesse
contents Lin, Chan (High order entropy stable discontinuous Galerkin spectral element methods through subcell limiting, 2024) enforces a cell entropy inequality for nodal discontinuous Galerkin methods by combining flux corrected transport (FCT)-type limiting and a knapsack solver, which determines optimal limiting coefficients that result in a semi-discrete cell entropy inequality while preserving nodal bounds. In this work, we provide a slight modification of this approach, where we utilize a quadratic knapsack problem instead of a standard linear knapsack problem. We prove that this quadratic knapsack problem can be reduced to efficient scalar root-finding. Numerical results demonstrate that the proposed quadratic knapsack limiting strategy is efficient and results in a semi-discretization with improved regularity in time compared with linear knapsack limiting, while resulting in fewer adaptive timesteps in shock-type problems.
format Preprint
id arxiv_https___arxiv_org_abs_2507_14488
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Entropy Stable Nodal Discontinuous Galerkin Methods via Quadratic Knapsack Limiting
Christner, Brian
Chan, Jesse
Numerical Analysis
Lin, Chan (High order entropy stable discontinuous Galerkin spectral element methods through subcell limiting, 2024) enforces a cell entropy inequality for nodal discontinuous Galerkin methods by combining flux corrected transport (FCT)-type limiting and a knapsack solver, which determines optimal limiting coefficients that result in a semi-discrete cell entropy inequality while preserving nodal bounds. In this work, we provide a slight modification of this approach, where we utilize a quadratic knapsack problem instead of a standard linear knapsack problem. We prove that this quadratic knapsack problem can be reduced to efficient scalar root-finding. Numerical results demonstrate that the proposed quadratic knapsack limiting strategy is efficient and results in a semi-discretization with improved regularity in time compared with linear knapsack limiting, while resulting in fewer adaptive timesteps in shock-type problems.
title Entropy Stable Nodal Discontinuous Galerkin Methods via Quadratic Knapsack Limiting
topic Numerical Analysis
url https://arxiv.org/abs/2507.14488