Nonzeros of SBAIJ

[Zhifeng Sheng]

Barry Smith wrote:

>
> Plus 1 for each row for the diagonal.
>
> Barry
>
>
> On Nov 12, 2007, at 11:16 AM, Hong Zhang wrote:
>
>>
>>
>> On Mon, 12 Nov 2007, Zhifeng Sheng wrote:
>>
>>> Dear all
>>>
>>> my matrix is SeqSBAIJ with block size 1, so I am wondering when I 
>>> specify the nonzeros in a row, does it mean the actually nonzeros 
>>> numbers or the memory that is needed? (for instance, for SeqSBAIJ, 
>>> the actual nonzeros in a row would twice as much as memory needed)
>>
>>
>> No, you specify the nonzeros of upper triangular part.
>>
>> Hong
>>
>>>
>>> Thank you
>>> Best regards
>>> Zhifeng
>>>
>>>
>>
>
Dear all

I allocated the memory exactly with symbolic computation, and tried 
preallocation on AIJ and SBAIJ, it works well for AIJ, no additional 
allocaiton is needed in assembly... then I did it on SBAIJ ( nonzeros of 
upper triangular part + 1), the performance is much worse , it seems 
that memory allocation was still needed... does anyone have such problem 
before?

Thank you
Best regards
Zhifeng Sheng