> simulation by means of second-kind Galerkin boundary element method.>> Source: Elke Spindler "Second-Kind Single Trace Boundary Integral>> Formulations for Scattering at Composite Objects", ETH Diss 23620, 2016."" > > simulation by means of second-kind Galerkin boundary element method.>> Source: Elke Spindler "Second-Kind Single Trace Boundary Integral>> Formulations for Scattering at Composite Objects", ETH Diss 23620, 2016."" > Research reports – Seminar for Applied Mathematics | ETH Zurich

Research reports

Multilevel Monte Carlo FEM for Elliptic PDEs with Besov Random Tree Priors

by Ch. Schwab and A. Stein

(Report number 2022-10)

Abstract
We develop a multilevel Monte Carlo (MLMC) FEM algorithm for linear, elliptic diffusion problems in polytopal domain \(\mathcal D\subset \mathbb R^d\), with Besov-tree random coefficients. This is to say that the logarithms of the diffusion coefficients are sampled from so-called Besov-tree priors, which have recently been proposed to model data for fractal phenomena in science and engineering. Numerical analysis of the fully discrete FEM for the elliptic PDE includes quadrature approximation and must account for a) nonuniform pathwise upper and lower coefficient bounds, and for b) low path-regularity of the Besov-tree coefficients. Admissible non-parametric random coefficients correspond to random functions exhibiting singularities on random fractals with tunable fractal dimension, but involve no a-priori specification of the fractal geometry of singular supports of sample paths. Optimal complexity and convergence rate estimates for quantities of interest and for their second moments are proved. A convergence analysis for MLMC-FEM is performed which yields choices of the algorithmic steering parameters for efficient implementation. A complexity (``error vs work'') analysis of the MLMC-FEM approximations is provided.

Keywords: Besov prior, Galton-Watson tree, Fractal models, Elliptic PDE with random coefficient, Finite element discretization, Multilevel Monte Carlo

BibTeX
@Techreport{SS22_998,
  author = {Ch. Schwab and A. Stein},
  title = {Multilevel Monte Carlo FEM for Elliptic PDEs with Besov Random Tree Priors},
  institution = {Seminar for Applied Mathematics, ETH Z{\"u}rich},
  number = {2022-10},
  address = {Switzerland},
  url = {https://www.sam.math.ethz.ch/sam_reports/reports_final/reports2022/2022-10.pdf },
  year = {2022}
}

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