[petsc-users] Conversion between AIJ & BAIJ

[Matthew Knepley]

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
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