Title
Numerical Homogenization of Heterogeneous Fractional Laplacians
Abstract
In this paper, we develop a numerical multiscale method to solve the fractional Laplacian with a heterogeneous diffusion coefficient. When the coefficient is heterogeneous, this adds to the computational costs. Moreover, the fractional Laplacian is a nonlocal operator in its standard form; however, the Caffarelli-Silvestre extension allows for a localization of the equations. This adds a complexity of an extra spacial dimension and a singular/degenerate coefficient depending on the fractional order. Using a subgrid correction method, we correct the basis functions in a natural weighted Sobolev space and show that these corrections are able to be truncated to design a computationally efficient scheme with optimal convergence rates. A key ingredient of this method is the use of quasi-interpolation operators to construct the fine scale spaces. Since the solution of the extended problem on the critical boundary is our main interest, we construct a projective quasi-interpolation that has both d and d + 1 dimensional averages over subsets in the spirit of the Scott-Zhang operator. We show that this operator satisfies local stability and local approximation properties in weighted Sobolev spaces. We further show that we can obtain a greater rate of convergence for sufficient smooth forces, utilizing a global L-2 projection on the critical boundary. We present some numerical examples, utilizing our projective quasi-interpolation in dimension 2 + 1 for analytic and heterogeneous cases to demonstrate the rates and effectiveness of the method.
Year
DOI
Venue
2018
10.1137/17M1147305
MULTISCALE MODELING & SIMULATION
Keywords
Field
DocType
localization,multiscale methods,fractional Laplacian,heterogeneous diffusion,nonlocal models
Convergence (routing),Degenerate energy levels,Homogenization (chemistry),Mathematical analysis,Sobolev space,Fractional Laplacian,Basis function,Operator (computer programming),Rate of convergence,Mathematics
Journal
Volume
Issue
ISSN
16
3
1540-3459
Citations 
PageRank 
References 
0
0.34
8
Authors
3
Name
Order
Citations
PageRank
Donald L. Brown1223.63
Joscha Gedicke2589.24
Daniel Peterseim310413.03