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

John Fettig john.fettig at gmail.com
Fri Dec 16 14:30:02 CST 2011


Barry,

Could you give me an idea of what needs to be done?  I'm definitely
interested in fixing this.

John

On Fri, Dec 16, 2011 at 3:03 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:

>
>   John,
>
>     I made a mistake in suggesting PCBJACOBI with cuda/cusp that is
> currently not workable with PETSc and requires some improvements to
> bjacobi.c to get it working.  We have no people here working on
> PETSc/CUDA-Cusp here nor very much knowledge about the subject. If you are
> a wizard at C and CUDA/CUSP we could step you through how to fix it,
> otherwise maybe someone else is willing to fix it?
>
>   Barry
>
>
> On Dec 16, 2011, at 1:38 PM, Satish Balay wrote:
>
> > On Wed, 14 Dec 2011, Satish Balay wrote:
> >
> >> On Wed, 14 Dec 2011, John Fettig 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?
> >>
> >>
> >> Looks like VecDuplicate() -> VecDuplicate_MPICUSP() is returning a
> >> 'mpi' Vec instead of 'mpicusp' Vec. [This is a bug?] will check..
> >
> > Pushed a fix for VecDuplicate_MPICUSP(). However this is not
> > sufficient to get bjacobi with cusp working.
> >
> > Satish
> >
>
>
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