[petsc-users] MatCreateMPIAIJ with zero size on some ranks

[Thomas Witkowski]

Is it possible to create a parallel matrix (MPIAIJ) with empty size on 
some ranks? Even if this should work, does it make sense (with respect 
to runtime and efficiency) to collect all ranks having a nonempty 
contribution the the global matrix in an mpi group and to use this 
communicator for matrix create/computations?

Thomas