> The new code is in https://gitlab.com/petsc/petsc/-/merge_requests/7293 and
> retains the null space on the submatrices for both MatZeroRows() and
> MatZeroRowsAndColumns() regardless of changes to the nonzero structure of the
> matrix.
Thank you very much Barry.
It works as expected.
--
The new code is in https://gitlab.com/petsc/petsc/-/merge_requests/7293 and
retains the null space on the submatrices for both MatZeroRows() and
MatZeroRowsAndColumns() regardless of changes to the nonzero structure of the
matrix.
Barry
> On Feb 13, 2024, at 7:12 AM, Jeremy Theler
Thank you for the code.
A) By default MatZeroRows() does change the nonzero structure of the matrix
B) PCFIELDSPLIT loses the null spaces attached to the submatrices if the
nonzero structure of the matrix changes.
For the example code if one sets MatSetOption(A,MAT_KEEP_NONZERO_PATTERN,
7279 does change the code for MatZeroRowsColumns_MPIAIJ(). But perhaps that
does not resolve the problem you are seeing? If that is the case we will need a
reproducible example so we can determine exactly what else is happening in your
code to cause the difficulties.
Here is the diff for
On Mon, Feb 12, 2024 at 7:10 AM Jeremy Theler (External) <
jeremy.theler-...@ansys.com> wrote:
> Hi Barry
>
> > The bug fix for 2 is availabel in
> https://gitlab.com/petsc/petsc/-/merge_requests/7279
>
> Note that our code goes through MatZeroRowsColumns_MPIAIJ() not through
>
Hi Barry
> The bug fix for 2 is availabel in
> https://gitlab.com/petsc/petsc/-/merge_requests/7279
Note that our code goes through MatZeroRowsColumns_MPIAIJ() not through
MatZeroRows_MPIAIJ() so this fix does not change anything for the case I
mentioned.
--
jeremy
The bug fix for 2 is availabel in
https://gitlab.com/petsc/petsc/-/merge_requests/7279
> On Feb 9, 2024, at 10:50 AM, Barry Smith wrote:
>
>
> 1. Code going through line 692 looses the near nullspace of the matrices
> attached to the sub-KSPs
> 2. The call to MatZeroRowsColumns()
1. Code going through line 692 looses the near nullspace of the matrices
attached to the sub-KSPs
2. The call to MatZeroRowsColumns() changes then non-zero structure for MPIAIJ
but not for SEQAIJ
(unless MAT_KEEP_NONZERO_PATTERN is used)
MatZeroRowsColumns() manual page states:
Unlike
> > Because of a combination of settings, our code passes through this line:
> >
> > https://gitlab.com/petsc/petsc/-/blob/main/src/ksp/pc/impls/fieldsplit/fieldsplit.c?ref_type=heads#L692
> >
> > i.e. the matrices associated with each of the sub-KSPs of a fieldsplit are
> > destroyed and then
On Fri, Feb 9, 2024 at 7:04 AM Jeremy Theler (External) <
jeremy.theler-...@ansys.com> wrote:
> Hi all
>
> Because of a combination of settings, our code passes through this line:
>
>
> https://gitlab.com/petsc/petsc/-/blob/main/src/ksp/pc/impls/fieldsplit/fieldsplit.c?ref_type=heads#L692
>
>
10 matches
Mail list logo