Set values of symmetric matrices.

[billy at dem.uminho.pt]

It exits with no error message. Usually I see several PETSC error messages
before it exits. I tested with MPIAIJ. It works with KSPGMRES or KSPBCGS but
with KSPCG it exits immediately. Maybe I am missing something.

Billy.


Quoting Hong Zhang <hzhang at mcs.anl.gov>:

> 
> Billy,
> 
> We support cg with MPIAIJ and MPISBAIJ format.
> 
> > I use MatCreateMPIAIJ to create parallel matrices. I would like to use
> KSPCG to
> > solve a symmetric matrices. I tried to implement it but the program exits
> with
> > no error.
>   ^^^^^^^
> Do you mean with error? If so, what error message?
> 
> >Do I need only to set values on the diagonal and upper diagonal only
> > or continue to set all non-zero entries of the matrix?
> >
> If you use MPISBAIJ matrix format, then you only need to set the diagonal
> and upper diagonals. Setting all non-zero entries of the matrix
> also works - petsc ignores the lower triangular part.
> 
> Hong
> >
> 
>