Examples
ex1.c: Test PCBDDCGraphCreateLocalSubdomainAdjacency() against the DMPlex facet graph.
ex2.c: Tests BDDC Nedelec support and user-defined primal vertices.
ex4.c: Tests BDDC reuse after PCReset() and KSPReset().
ex5.c: Tests BDDC coarse solver reuse when the coarse MPI communicator changes.