[petsc-users] 2-stage preconditioner

[Peter Brune]

PCComposite is probably the answer

http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/PC/PCCOMPOSITE.html

The multiplicative variant will call one after the other.  In order to nest
it you may have to register your own custom type rather than using shell;
this is doable with

http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/PC/PCRegister.html

- Peter


On Tue, Apr 22, 2014 at 9:43 AM, Qin Lu <lu_qin_2000 at yahoo.com> wrote:

> Hello,
>
> I need to implement a 2-stage preconditioner using PETSc linear solver:
>
> 1. The first stage uses a user-provided preconditioner routine. It seems I
> can set it with PCShellSetApply.
> 2. The second stage uses PETSc's ILU.
>
> Shall I just call this two preconditioners in sequence, or there is a
> particular way to hook them up? Is there any sample code for this?
>
> Many thanks for your suggestions.
>
> Best Regards,
> Qin
>
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