>> Yes, modern direct solver do block factorization as super node method. >> Can ASM type preconditioner use superlu ILUT on each subdomain? > > Yes. Yes. Example ~petsc/src/ksp/ksp/examples/tutorials>mpiexec -n 2 ./ex2 -pc_type asm -sub_pc_type ilu -sub_pc_factor_mat_solver_package superlu -ksp_view
Hong >> >> At preset, my solver (BCGS) only works with ASM+ILU(1) on a "smart >> partitioned" mesh. >> >> >> > The ILUTP in SuperLU (4.2 and up) exploits blocking (supernodes) in >> > >> > the (approximate) L & U factors. ?Note the block boundary is >> > >> > discovered on the fly, which is usually larger than the block size >> > >> > from the input matrix A. ?So the efficiency is pretty good. ?It uses >> > >> > threshold dropping with partial pivoting, numerically is quite good >> > >> > too. ? ?It's available only in the serial version. >> > >> > >> > >> > Sherry Li >> > >> > >> > >> > >> > >> > On Sun, Oct 30, 2011 at 11:18 PM, Jed Brown <jedbrown at mcs.anl.gov> >> > wrote: >> > >> > > On Sun, Oct 30, 2011 at 23:50, Gong Ding <gdiso at ustc.edu> wrote: >> > >> > >> >> > >> > >> I had also considered use max block size. But it is not efficient >> > >> here. >> > >> > >> Hope petsc support nonuniform block size one day. >> > >> > > >> > >> > > Inodes do a sort of partial blocking. There has to a clear performance >> > >> > > benefit to explicit variable blocking in order to justify the >> > > implementation >> > >> > > and interface complexity. I have not yet seen a demonstration of this. >> > >> > > > > > -- > What most experimenters take for granted before they begin their experiments > is infinitely more interesting than any results to which their experiments > lead. > -- Norbert Wiener >
