Hi, I got the option for pilut from help: ------------ -pc_hypre_pilut_maxiter <-2> -pc_hypre_pilut_tol <-2> -pc_hypre_pilut_factorrowsize <-2 > ------------ What are the default values? "-pc_hypre_pilut_tol " is 0.001? "-pc_hypre_pilut_factorrowsize" is 20? And I do not understand the option "-pc_hypre_pilut_maxiter". Thanks, Hui