[petsc-users] Stokes problem with DA and MUMPS

[gouarin]

I already use petsc-dev and DMComposite.

I call PCSetDM and it works.

Thanks,
Loic

On 24/02/2011 11:09, Jed Brown wrote:
> On Thu, Feb 24, 2011 at 10:56, gouarin <loic.gouarin at math.u-psud.fr 
> <mailto:loic.gouarin at math.u-psud.fr>> wrote:
>
>     I set block size to 3 for my matrix but I'm not sure that I can
>     use it because I don't have the same number of points for each
>     field. I don't hnow how petsc defines the blocks.
>
>     How can I use again fieldsplit for the preconditioner ?
>
>
> It is worth switching to petsc-dev for this:
>
> 1. Use DMComposite to "glue" the velocity and pressure DAs together.
>
> 2. Call PCSetDM (or the higher level KSPSetDM, SNESSetDM, or TSSetDM 
> as appropriate) and pass in the DMComposite.
>
> Now when you -pc_type fieldsplit, it will automatically pick up the 
> fields from the DMComposite (in the order they were registered). That 
> would give you two splits in this case.
>
> You can use DMComposite with petsc-3.1, but you have to create index 
> sets yourself and call PCFieldSplitSetIS().


-- 
Loic Gouarin
Laboratoire de Mathématiques
Université Paris-Sud
Bâtiment 425
91405 Orsay Cedex
France
Tel: (+33) 1 69 15 60 14
Fax: (+33) 1 69 15 67 18

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