BAIJ and AIJ formats

[Hong Zhang]

Manav,

If your matrix can be stored as BAIJ
with dense blocks, then using BAIJ would be
more memory efficient.
See slides 42 of
http://www-unix.mcs.anl.gov/petsc/petsc-as/documentation/tutorials/LCRC-06.pdf.

Hong

On Sun, 28 Sep 2008, Manav Bhatia wrote:

> One more question:
> When is it advantageous to use BAIJ format instead of AIJ?
>
> Thanks,
> Manav
>
>
> On Sep 28, 2008, at 3:48 PM, Manav Bhatia wrote:
>
>> Hi,
>>
>>   I have a few questions about the block format matrix.
>>
>>    In the function: MatCreateSeqBAIJ, the arguments are
>> 
>> bs	- size of block
>> m	- number of rows
>> n	- number of columns
>> nz	- number of nonzero blocks per block row (same for all rows)
>> nnz	- array containing the number of nonzero blocks in the various block 
>> rows (possibly different for each block row) or PETSC_NULL
>> 
>> If I specify the nnz vector, then what is the dimension of this vector? Is 
>> that equal to the block size? If so, then is it assumed that all blocks 
>> have the same number of non-zeros per row?
>> 
>> If my blocks have different non-zero patterns, then should I use an AIJ 
>> format instead of a BAIJ format?
>> 
>> Thanks,
>> Manav
>