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

[Satish Balay]

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