[petsc-users] Conversion between AIJ & BAIJ

[Matthew Knepley]

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?

  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
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