V-cycle Multigrid Algorithms for Discontinuous Galerkin Methods on Non-nested Polytopic Meshes

摘要

In this paper we analyze the convergence properties of V-cycle multigrid algorithms for the numerical solution of the linear system of equations stemming from discontinuous Galerkin discretization of second-order elliptic partial differential equations on polytopic meshes. Here, the sequence of spaces that stands at the basis of the multigrid scheme is possibly non-nested and is obtained based on employing agglomeration algorithms with possible edge/face coarsening. We prove that the method converges uniformly with respect to the granularity of the grid and the polynomial approximation degree p, provided that the minimum number of smoothing steps, which depends on p, is chosen sufficiently large.