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Main Authors: Eyob, Brook, Schäfer, Florian
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2505.10713
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author Eyob, Brook
Schäfer, Florian
author_facet Eyob, Brook
Schäfer, Florian
contents The transport of positive quantities underlies countless physical processes, including fluid, gas, and plasma dynamics. Discretizing the associated partial differential equations with Galerkin methods can result in spurious nonpositivity of solutions. We observe that these methods amount to performing statistical inference using the method of moments (MoM) and that the loss of positivity arises from MoM's susceptibility to producing estimates inconsistent with the observed data. We overcome this problem by replacing MoM with maximum likelihood estimation, introducing $\textit{maximum likelihood discretization} $(MLD). In the continuous limit, MLD simplifies to the Fisher-Rao Galerkin (FRG) semidiscretization, which replaces the $L^2$ inner product in Galerkin projection with the Fisher-Rao metric of probability distributions. We show empirically that FRG preserves positivity. We prove rigorously that it yields error bounds in the Kullback-Leibler divergence.
format Preprint
id arxiv_https___arxiv_org_abs_2505_10713
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Maximum likelihood discretization of the transport equation
Eyob, Brook
Schäfer, Florian
Numerical Analysis
Computation
35L65, 76L05, 65M25, 76J20, 58B20
The transport of positive quantities underlies countless physical processes, including fluid, gas, and plasma dynamics. Discretizing the associated partial differential equations with Galerkin methods can result in spurious nonpositivity of solutions. We observe that these methods amount to performing statistical inference using the method of moments (MoM) and that the loss of positivity arises from MoM's susceptibility to producing estimates inconsistent with the observed data. We overcome this problem by replacing MoM with maximum likelihood estimation, introducing $\textit{maximum likelihood discretization} $(MLD). In the continuous limit, MLD simplifies to the Fisher-Rao Galerkin (FRG) semidiscretization, which replaces the $L^2$ inner product in Galerkin projection with the Fisher-Rao metric of probability distributions. We show empirically that FRG preserves positivity. We prove rigorously that it yields error bounds in the Kullback-Leibler divergence.
title Maximum likelihood discretization of the transport equation
topic Numerical Analysis
Computation
35L65, 76L05, 65M25, 76J20, 58B20
url https://arxiv.org/abs/2505.10713