[petsc-users] How to use multigrid?

[Mark F. Adams]

yes 
On Nov 9, 2012, at 12:26 PM, "A.L. Siahaan" <als88 at cam.ac.uk> wrote:

> Thank's a lot, Mark ! What does 'native' mean here ? That it is PETSc's built-in and not interface ?
> 
> Antony
> 
> On Nov 9 2012, Mark F. Adams wrote:
> 
>>> Of all algebraic multigrid implemented or interfaced in PETSc, i.e. BoomerAMG (PCHypre), ML(PCML), and PCGAMG("agg"), what is the order of the cost (memory) to set up the preconditioner (setting nullspace etc) ?
>> 
>> Not a simple question. ML and GAMG use very similar algorithms and ML is implemented in a more "native" way than hypre (GAMG is completely native). GAMG/ML are probably better for elasticity, hypre is great for 2D low order discretizations of Laplacian, and it is a very hardened implementation. hypre is not native so there are some things that don't work as well.
>> 
>>> Regards,
>>> Antony
> 
>