[petsc-users] Solving Poisson equation with multigrid

[Jed Brown]

Michele Rosso <mrosso at uci.edu> writes:

> So should I always use an odd number of grid points?
> There is no way around this?

If you want to use regular geometric coarsening, then yes.  That *is*
regular node-centered coarsening.  Just consider the base case of one
element:


  o ------- o

Split that in two:

  o -- o -- o

Look, an odd number of vertices, and as we keep refining, it will stay
odd.

You can use AMG or write your own interpolation if you want irregular coarsening.