[petsc-users] Conversion between AIJ & BAIJ

[Matthew Knepley]

On Wed, Jan 21, 2015 at 1:55 PM, Chung-Kan Huang <ckhuangf at gmail.com> wrote:

>
> On Wed, Jan 21, 2015 at 1:44 PM, Matthew Knepley <knepley at gmail.com>
> wrote:
>
>> On Wed, Jan 21, 2015 at 1:40 PM, Chung-Kan Huang <ckhuangf at gmail.com>
>> wrote:
>>
>>> Then A & AB are not longer the same matrix.  They become complete two
>>> individuals aren't they?
>>> If I do whatever to AB after AB is created the A is still the same old A
>>> and not going to be affected by the operations I do to AB.
>>>
>>
>> Yes.
>>
>>
>>>
>>> What I am really looking for is a way to create two interfaces (one as
>>> AIJ and one as BAIJ) but they both refer to the same matrix.
>>>
>>
>> Why would you ever want this? Why not just using BAIJ?
>>
> As I mentioned in the beginning.  There are parts of the code gets benifit
> when AIJ is used and the other part gets benifit  if BAIJ is used.
>
> For instance,
>
> I'd like to use MatSetValuesBlocked but I also want to use ilu constructed
> by AIJ instead of BAIJ (our experience found ilu from BAIJ behaves funny
> sometimes.
>

If the blocks truly are dense, then ILU(0) is identical on both.

  Matt


> Thanks,
>
> Kan
>
>>
>>   Thanks,
>>
>>       Matt
>>
>>
>>> Thanks,
>>>
>>> Kan
>>> On Wed, Jan 21, 2015 at 1:20 PM, Matthew Knepley <knepley at gmail.com>
>>> wrote:
>>>
>>>> On Wed, Jan 21, 2015 at 12:56 PM, Chung-Kan Huang <ckhuangf at gmail.com>
>>>> wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> So if I do
>>>>>
>>>>> Mat A, AB;
>>>>> MatCreateAIJ(comm,m,n,M,N,d_nz, d_nnz,o_nz, o_nnz, &A);
>>>>> MatConvert(A, MATBAIJ, MAT_INITAL_MATRIX, &AB);
>>>>> MatSetBlockSize(AB, bs)
>>>>> I can create AB as a BAIJ with block size of bs from A which is a AIJ
>>>>> matrix.
>>>>>
>>>>> So from this point I can use both A and AB and they will mean the same
>>>>> matrix. Am I right?
>>>>>
>>>>
>>>> Yes
>>>>
>>>>
>>>>> At the end of the program do I only destory one of them or both?
>>>>>
>>>>
>>>> Both
>>>>
>>>>
>>>>> Do I need to worry about anything in terms of memory penalty?
>>>>>
>>>>
>>>> It is twice the memory. Its another matrix.
>>>>
>>>> Did you catch when Jed said you could jsut create the BAIJ up front?
>>>>
>>>>   Thanks,
>>>>
>>>>     Matt
>>>>
>>>>
>>>>>
>>>>> Thanks,
>>>>>
>>>>> Kan
>>>>>
>>>>>
>>>>> On Tue, Jan 20, 2015 at 4:39 PM, Barry Smith <bsmith at mcs.anl.gov>
>>>>> wrote:
>>>>>
>>>>>>
>>>>>>   You can do a MatConvert() (requires another copy of the matrix) for
>>>>>> the parts that benefit from BAIJ.
>>>>>>
>>>>>>   Barry
>>>>>>
>>>>>> > On Jan 20, 2015, at 4:33 PM, Chung-Kan Huang <ckhuangf at gmail.com>
>>>>>> wrote:
>>>>>> >
>>>>>> > Hi,
>>>>>> >
>>>>>> > Does PETSc provide means for conversion between AIJ & BAIJ.
>>>>>> >
>>>>>> > My matrix is created as AIJ because it makes life easy for most
>>>>>> part of the applications but some part of applications actually get some
>>>>>> benefits with BAIJ.  So I wonder if a matrix can exist as two idenfities
>>>>>> and I can use either format depend on which one is more convenient at run
>>>>>> time.
>>>>>> >
>>>>>> > So in my case the block size is fixed and identical for all blocks.
>>>>>> >
>>>>>> >
>>>>>> > Thanks,
>>>>>> >
>>>>>> >
>>>>>> > Kan
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>> --
>>>>>
>>>>> *Cheers*
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> 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
>>>>
>>>
>>>
>>>
>>> --
>>>
>>> *Cheers*
>>>
>>
>>
>>
>> --
>> 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
>>
>
>
>
> --
>
> *Cheers*
>



-- 
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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