On Thu, Nov 11, 2010 at 17:03, Tim Kroeger <tim.kroeger@cevis.uni-bremen.de> wrote:

One more question: Does this bux and fix also apply to a submatrix of an MPIAIJ matrix? That is, can I safely use MatMultAdd() having v2==v3 for such a matrix in 3.1.0-p4 or not? (I'm having trouble with such a matrix now, but the error might be on my side.)

MPIAIJ implements MatGetSubMatrix, so it returns a new, efficient MatMPIAIJ matrix. This patch only affects matrix types that do not implement MatGetSubMatrix, and thus fall back on creating a MatSubMatrix (which just holds a reference to the original matrix and implements multiplication through scatters).

So calling MatMultAdd using a matrix of any type other than MatSubMatrix is unrelated to my patch.

Jed