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

[Matthew Knepley]

On Sun, Mar 1, 2015 at 5:03 PM, Fande Kong <fd.kong at siat.ac.cn> wrote:

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

I think you are asking about variable block size in the matrix. We do not
support that.

  Thanks,

     Matt


> 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
>>
>
>


-- 
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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