Monotone Multigrid Methods for Variational Inequalities II

Ralf Kornhuber
Konrad-Zuse-Zentrum Berlin
Heilbronner Str. 10
D-10711 Berlin
Germany

Abstract

We derive fast solvers for discrete elliptic variational inequalities of the second kind as resulting from the approximation by piecewise linear finite elements. Following the first part of this paper, monotone multigrid methods are considered as extended underrelaxations. Again, the coarse grid corrections are localized by suitable constraints, which in this case are fixed by fine grid smoothing. We consider the standard monotone multigrid method induced by the multilevel nodal basis and a truncated version. Global convergence results and asymptotic estimates for the convergence rates are given. The numerical results indicate a significant improvement in efficiency compared with previous multigrid approaches.


Contributed April 8, 1994.