[petsc-dev] sacusp preconditioner - limited to seqaijcusp matrices?

[Matthew Knepley]

On Wed, Dec 14, 2011 at 2:21 PM, John Fettig <john.fettig at gmail.com> wrote:

> On Tue, Sep 20, 2011 at 12:58 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:
>
>>
>> On Sep 20, 2011, at 11:54 AM, Brad Aagaard wrote:
>>
>> > I tried running a PyLith simulation using the sacusp preconditioner
>> rather than ml. If I have the mat_type set to mpiaijcusp, I get an error
>> message that sacusp preconditioner only works with CUSP matrices. I checked
>> sacusp.c and the code checks to make sure the mat_type is seqaijcusp.
>>
>>    Since the sacusp preconditioner is no MPI parallel it cannot deal with
>> MPI matrices. ML is a truly (MPI) parallel multi-level preconditioner so it
>> is not really interchangable with sacusp.
>>
>>    You can use block Jacobi preconditioning -pc_type bjacobi -sub_pc_type
>> sacusp   with sacusp on each block.
>
>
> Hi Barry,
>
> Sorry to dig up a very old thread, but I just tried your suggestion of
> using block jacobi with sacusp on the blocks and I can't get it to work.
> For example, I run src/ksp/ksp/examples/tutorials/ex2.c with:
>
>  mpirun -np 2 ./ex2 -ksp_type cg -pc_type bjacobi -sub_pc_type sacusp
> -mat_type mpiaijcusp -vec_type mpicusp
>
> and it still bombs on line 139 of sacusp.cu because the vector type is
> not VECSEQCUSP.  What am I doing wrong?
>

You might need -vec_type cusp (should give seqcusp on 1 proc)

  Matt


> Thanks,
> John
>
>


-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener
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