[petsc-users] Assembly of local Mat's to a parallel Mat

[Jed Brown]

Hui Zhang <mike.hui.zhang at hotmail.com> writes:

> Thanks!  My difficulty lie in that Ai is a result of matrix computations in a 
> sub-communcator (of the communicator of A).  So I do not know a priori 
> the non-zero structure of Ai.  Following the instructions of you, I think 
> I need to first MatGetRow of Ai, then MatSetValues to A. Is there a better way?

When they're on different communicators, this is the recommended way.