[petsc-users] Conversion between AIJ & BAIJ

[Chung-Kan Huang]

On Wed, Jan 21, 2015 at 2:15 PM, Matthew Knepley <knepley at gmail.com> wrote:

> On Wed, Jan 21, 2015 at 2:07 PM, Chung-Kan Huang <ckhuangf at gmail.com>
> wrote:
>
>>
>> On Wed, Jan 21, 2015 at 2:01 PM, Matthew Knepley <knepley at gmail.com>
>> wrote:
>>
>>> 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.
>>>
>>
>> Unfortunately the life is not that easy.  The blocks are spares and we
>> found ILU(1) works better for our case.
>> And besides that is not the only reason I want to have AIJ & BAIJ
>> interfaces, we have some code management issue and I am looking for short
>> cut to unite them.
>>
>> So go back to the original question the short answer is no way?
>>
>
> Yes, it would not make sense.
>
> What problem are you using ILU(1) for?
>

I am using it for flow simulation for reservoir problems.

Some issues we found is that
1) for a * x = 0 it doesn't return x = 0
2) After compared ILU(1) with BAIJ against with ILU(1) with AIJ I found
latter one is better.  I could not find anything wrong with my BAIJ version
though.  However, experiences suggested that BAIJ's ILU(1) should be better.


Thanks,

Kan

>
>   Thanks,
>
>      Matt
>
>
>> Thanks,
>>
>> Kan
>>
>>>
>>>   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
>>>
>>
>>
>>
>> --
>>
>> *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*
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