[petsc-users] Symmetric matrix filling

[Matthew Knepley]

On Wed, Nov 30, 2011 at 10:08 AM, Alexander Grayver <agrayver at gfz-potsdam.de
> wrote:

> **
> On 30.11.2011 16:22, Matthew Knepley wrote:
>
> On Wed, Nov 30, 2011 at 9:10 AM, Alexander Grayver <
> agrayver at gfz-potsdam.de> wrote:
>
>>  I'm not sure that MAT(S)BAIJ is what I need. My matrix symmetric, but
>> not block.
>> Well, I solve vector equations and there are 2-3 blocks (depending on the
>> problem dimension), but this blocks normaly have size of > 10^5. So which
>> block size should I specify to be efficient?
>>
>
>  Just use 1.
>
>
> And for d_nz/o_nz also 1?
>

No, preallocate for the nonzeros you enter, as normal.

  Matt


>    Matt
>
>
>>  Regards,
>> Alexander
>>
>> On 30.11.2011 14:27, Alexander Grayver wrote:
>>
>> Thanks Matt!
>>
>> Regards,
>> Alexander
>>
>> On 30.11.2011 14:16, Matthew Knepley wrote:
>>
>> On Wed, Nov 30, 2011 at 3:43 AM, Alexander Grayver <
>> agrayver at gfz-potsdam.de> wrote:
>>
>>> Hello,
>>>
>>> I'm trying to use mumps through PETSc now with symmetric matrix and
>>> cholesky factorization.
>>> When I use it directly I fill up only upper part of the matrix and set
>>> mumid%SYM = 2. Is that possible to follow same way with petsc?
>>> Which options do I have to choose?
>>>
>>
>>
>> http://www.mcs.anl.gov/petsc/petsc-dev/docs/manualpages/Mat/MATSBAIJ.html
>>
>>    Matt
>>
>>
>>> Thanks in advance.
>>>
>>> Regards,
>>>  Alexander
>>>
>>
>>
>>
>>  --
>> 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
>
>
>


-- 
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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