[petsc-users] how to switch ILU to its block version?

[Fande Kong]

Thanks, Matt.

Could bs be different from rows. I am solving a fluid-structure problem,
which has different bs in fluid and solid parts.

Fande,

On Sun, Mar 1, 2015 at 3:57 PM, Matthew Knepley <knepley at gmail.com> wrote:

> On Sun, Mar 1, 2015 at 4:55 PM, Fande Kong <fd.kong at siat.ac.cn> wrote:
>
>> Thanks, Barry.
>>
>> More questions. Is bs usually the number of unknowns associated with a
>> grid point. Do I need to change MatSetValues if use a MATSEQBAIJ matrix?
>>
>
> No, but it does enable you to use MatSetValuesBlock() if you want.
>
>    Matt
>
>
>> Fande,
>>
>> On Sun, Mar 1, 2015 at 2:36 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:
>>
>>>
>>>   Fande,
>>>
>>>     The MATSEQBAIJ matrix automatically uses a point block ILU; with the
>>> block size of the matrix. So if your matrix naturally has a block size bs
>>> if you use the MATSEQBAIJ matrix type it will be point block ILU of block
>>> size bs.
>>>
>>>     We don't have a variable point block ILU in PETSc for SeqAIJ. It is
>>> possible to write but would be rather involved.
>>>
>>>    Barry
>>>
>>> > On Mar 1, 2015, at 1:47 PM, Fande Kong <fd.kong at siat.ac.cn> wrote:
>>> >
>>> > Hi all,
>>> >
>>> > I have a code with ILU as subdomain solver, and it works well. Now I
>>> want to try a block version of ILU, there are some easy ways to implement
>>> this?
>>> >
>>> > Fande,
>>>
>>>
>>>
>>
>
>
> --
> What most experimenters take for granted before they begin their
> experiments is infinitely more interesting than any results to which their
> experiments lead.
> -- Norbert Wiener
>
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