[petsc-dev] Solving systems with (K,M)AIJ

[Pierre Jolivet]

Hello,
When solving systems with a KSP that has a (K,M)AIJ Pmat attached to it, it may be nice to define a preconditioner on the inner AIJ Pmat, so that we are not stuck with PCPBJACOBI.
For example, with FS, there is PCFieldSplitGetSubKSP and then you do what you want with the inner blocks.
Is there something similar for (K,M)AIJ, maybe with a fancy PCCOMPOSITE?
Of course, I could simply write a shell, but a new PC/option could be added to deal with such Pmat types?

Thanks,
Pierre