Solve a symmetric matrix

Hong Zhang hzhang at
Fri Oct 12 09:06:43 CDT 2007

> > PCILU and PCICC are not supported for MPISBAIJ matrix type
> > (the error message should indicate this problem).
> > For sequential sbaij matrix, you can use PCICC.
> > For parallel, you may try the default petsc preconditioner
> > block jacobi + icc. See Chapter 4 of petsc user manual.
> >
> Ok i see.
> The problem came from the call to KSPSetUp, when using one MPI task,
> this call end in MatILUFactorSymbolic with the error message about
> symbolic ILU with Matrix type seqsbaij.
> With more than one MPI task, there is no more error.

I would suggest you using '-ksp_view' to check which default solvers
are being used for both cases.
I guess the "block jacobi + icc" is used on parallel implementation.


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