[petsc-users] Does PETSc have some functions like A.*B, A./B in Matlab?
Yujie
recrusader at gmail.com
Sun Feb 21 14:44:55 CST 2010
I need do it for many. Actually, we don't consider a vector. Generally, if A
is dense matrix (nonzero entries) and B is sparse matrix, MatGetRow()
doesn't work when doing A.*B or A./B directly, right?
Thanks a lot.
Regards,
Yujie
On Sun, Feb 21, 2010 at 2:41 PM, Jed Brown <jed at 59a2.org> wrote:
> On Sun, 21 Feb 2010 14:33:23 -0600, Yujie <recrusader at gmail.com> wrote:
> > Thanks very much, Jed.
> > I have a vector (V) and a matrix (A),
> > I want to do Row_i_A.*V or Row_i_A./V (Row_i_A are the rows of A).
> However,
> > V has different format with the rows of A.
>
> You need to do this for a small number of rows (values of i), or for
> many? Since vectors are dense, and since MatGetValues only provides the
> local part, this is not scalable.
>
> What is the problem you are trying to solve with this algebraic
> manipulation? There is probably a scalable way to formulate the
> higher-level objective to avoid these shenanigans.
>
> Jed
>
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