[petsc-dev] Bug in MatZeroRows_MPIAIJ

[Lisandro Dalcin]

On 22 June 2016 at 00:30, Barry Smith <bsmith at mcs.anl.gov> wrote:
>  Why not just remove the first if test (below) and just have the two conditions diag != 0.0 and drag == 0.0
>
>      if ((diag != 0.0) && (mat->A->rmap->N == mat->A->cmap->N)) {
>         ierr = MatZeroRows(mat->A, len, lrows, diag, NULL, NULL);CHKERRQ(ierr);

What about comparing mat->rmap->N and mat->cmap->N, then compare
size(mat->rmap->comm) and size(mat->cmap->comm), and finally compare
(memcmp) mat->rmap-range and mat->rmap-range? If everything matches,
the row&col layout is square, you know that in all processes so no
need to do reductions, and then  you can take the fast path zeroing
rows on the diagonal block mat->A.


-- 
Lisandro Dalcin
============
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