Re: Nonzeros of SBAIJ

[Zhifeng Sheng <z.sheng@xxxxxxxxxxxxxx>]

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