[petsc-users] How to use multigrid?

[A.L. Siahaan]

When you mentioned that ML is implemented in a more "native" way than 
Hypre, did you mean that PCML is not exactly a PETSc's interface to the 
Trilinos ML ?

On Nov 9 2012, Mark F. Adams wrote:

>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
>> 
>> 
>
>