Dear PETSc Users, I want to use multigrid to solve uniform (just Laplace) poisson in 2D/3D on cartesian, non- uniform meshes with a standard 5 (7)-points stencil FD.
I always scaled my Poisson matrix like in the doc examples, i.e. multiplying by dx*dy (so that in ComputeRHS I need to scale b, in A*x = b, as well). This always worked properly with both MG/ GAMG and with galerkin matrices. Now I'd like to use non-uniform meshes, therefore the scaling is non-uniform. However I cannot get my matrices to scale properly with any sort of multigrid. One would think that without scaling, i.e. solving the original system, at least MG+galerkin or GAMG should work anyways provided the matrix A and b are consistent. I tried without boundaries (i.e. torus), so this is not the problem. Anyone did/knows how to do this properly? Thanks, F
