Can I use MatSetBlockSize() for MPIAIJ

[Ryan Yan]

Hi Jed,
Thanks,
So the following is very confusing:

http://www.mcs.anl.gov/petsc/petsc-as/snapshots/petsc-current/docs/manualpages/Mat/MatSetValuesBlocked.html

Notes The m and n count the NUMBER of blocks in the row direction and column
direction, NOT the total number of rows/columns; for example, if the block
size<http://www.mcs.anl.gov/petsc/petsc-as/snapshots/petsc-current/docs/manualpages/Sys/size.html#size>is
2 and you are passing in values for rows 2,3,4,5 then m would be 2
(not
4). The values in idxm would be 1 2; that is the first index for each block
divided by the block
size<http://www.mcs.anl.gov/petsc/petsc-as/snapshots/petsc-current/docs/manualpages/Sys/size.html#size>.


Note that you must call
MatSetBlockSize<http://www.mcs.anl.gov/petsc/petsc-as/snapshots/petsc-current/docs/manualpages/Mat/MatSetBlockSize.html#MatSetBlockSize>()
when constructing this matrix (and before preallocating it).........




On Sat, Nov 7, 2009 at 3:12 PM, Jed Brown <jed at 59a2.org> wrote:

> Ryan Yan wrote:
> > Hi All,
> > I have a question as follows:
> >
> > In order to use MatSetValuesBlocked() for a MPIAIJ matrix. I need to
> > call MatSetBlockSize() when I create the matrix.
>
> Call MatSetBlockSize *after* preallocation.
>
> Jed
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20091107/d160b583/attachment.htm>