Nonlinear Schwarz-Fas Methods for Unstructured Finite Element Elliptic Problems.

Jones, J. E. ; Vassilevski, P. S. ; Woodward, C. S.

Technical Information Center Oak Ridge Tennessee

关键词: Finite element methods;    Unstructured meshes;    Agglomeration;    Algorithms;    Performance;   

RP-ID  :  DE200415007244

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

This paper provides extensions of an element agglomeration AMG method to nonlinear elliptic problems discretized by the finite element method on general unstructured meshes. The method constructs coarse discretization spaces and corresponding coarse nonlinear operators as well as their Jacobians. We introduce both standard (fairly quasi-uniformly coarsened) and non-standard (coarsened away) coarse meshes and respective finite element spaces. We use both kind of spaces in FAS type coarse subspace correction (or Schwarz) algorithms. Their performance is illustrated on a number of model problems. The coarsened away spaces seem to perform better than the standard spaces for problems with nonlinearities in the principal part of the elliptic operator.