[Trilinos-Users] IfPack_AdditiveSchwarz with custom blocks

[Roberts, Nathan V.]

Dear Trilinos-Users,

I'm using an IfPack_AdditiveSchwarz smoother as a component in a preconditioner.  At present, the way this works is that the Schwarz blocks are "greedy" in that they use all the locally-available coefficients in the matrix; there is just one Schwarz block on each MPI rank.  For a variety of reasons, including the fact that I'd like to do some strong scaling experiments, I would like to be able to specify smaller blocks, so that there may be several on each MPI rank.

To be specific, in one use case, what I'd like is to have one Schwarz block per cell in my finite element discretization.  Since I know what rows correspond to that cell, in principle it's simple for me to provide the rows that I want for the Schwarz block.

Is this something that I can reasonably do with IfPack_AdditiveSchwarz?

Thanks for any assistance you can provide.

Regards,
Nate