On Wed, 13 Jan 2016, Justin Chang wrote: > Hi all, > > What exactly is the difference between these two preconditioners? When I > use them to solve a Galerkin finite element poisson problem, I get the > exact same performance (iterations, wall-clock time, etc).
you mean - when you run sequentially? With block jacobi - you decide the number of blocks. The default is 1-block/proc i.e - for sequnetial run you have only 1block i.e the whole matrix. So the following are essentially the same: -pc_type bjacobi -pc_bjacobi_blocks 1 [default] -sub_pc_type ilu [default] -pc_type ilu Satish > Only thing is I can't seem to use ILU in parallel though.
