Re: HYPRE with multiple variables

[Shaman Mahmoudi <shma7099@xxxxxxxxxxxxx>]

Hi Nicolas,

You are right. hypre has changed a lot since the version I used.

I found this interesting information:

int HYPRE_BOOMERAMGSetNodal(....)

Sets whether to use the nodal systems version. Default is 0.

Then information about smoothers:

One interesting thing there is this,

HYPRE_BoomerAMGSetDomainType(....)

0 - each point is a domain (default)
1 each node is a domain (only of interest in systems AMG)
2 ....

I could not find how you define the nodal displacement ordering. But  
it should be there somewhere.

I read the reference manual for hypre 2.0

With best regards, Shaman Mahmoudi


On Apr 13, 2007, at 1:40 PM, Nicolas Bathfield wrote:

> Dear Shaman,
>
> As far as I could understand, there is a BoomerAMG’s systems AMG  
> version
> available. This seems to be exactly what I am looking for, but I just
> don't know how to access it, either through PETSc or directly.
>
> Best regards,
>
> Nicolas
>
> > Hi,
> >
> > You want to exploit the structure of the model?
> > As far as I know, boomeramg can not treat a set of rows or blocks as
> > a molecule,  a so called block-smoother?
> > ML 2.0 smoothed aggregation does support it.
> >
> > With best regards, Shaman Mahmoudi
> >
> > On Apr 13, 2007, at 10:45 AM, Nicolas Bathfield wrote:
> >
> > > Hi,
> > >
> > > I am solving the Navier-stokes equations and try to use Hypre as
> > > preconditioner.
> > > Until now, I used PETSc as non-segregated solver and it worked
> > > perfectly.
> > > Things got worse when I decided to use Boomeramg (Hypre).
> > > As I solve a system of PDEs,  each cell is represented by 5 rows  
> > > in my
> > > matrix (I solve for 5 variables). PETSc handles that without problem
> > > apparently, but the coarsening scheme of Boomeramg needs more  
> > > input in
> > > order to work properly.
> > >
> > > Is there an option in PETSc to tell HYPRE that we are dealing with a
> > > system of PDEs? (something like:  -pc_hypre_boomeramg_...)
> > >
> > >
> > > Thanks for your help.
> > >
> > > Best regards,
> > >
> > > Nicolas
> > >
> > >
> > > --
> > > Nicolas BATHFIELD
> > > Chalmers University of Technology
> > > Shipping and Marine Technology
> > > phone: +46 (0)31 772 1476
> > > fax:   +46 (0)31 772 3699
>
>
> --
> Nicolas BATHFIELD
> Chalmers University of Technology
> Shipping and Marine Technology
> phone: +46 (0)31 772 1476
> fax:   +46 (0)31 772 3699