On Tue, Feb 9, 2021 at 4:31 AM Chen Gang <569615...@qq.com> wrote: > Dear Professor, > > I have a question about the bjacobi+ilu, I'm in the place > > src/ksp/ksp/tutorials > > and running the ex2 with > > mpirun -np 40 -bind-to core ./ex2 -m 2000 -n 2000 -ksp_max_it 1000000 > -ksp_rtol 1e-10 -ksp_type gmres -pc_type bjacobi -sub_pc_type ilu > -sub_pc_factor_levels 10 -ksp_monitor_short > > on the Intel machine with 40 cores, the petsc is complied with MKL and > ICC/MPIICC with O3. > > I found the numerical results are not the same from time to time, although > they all right, the iterations are not exactly the same from time to time. > Where have I done wrong? >
Humm, iterations should rarely change. You can see floating point scale differences. Try jacobi instead of ilu and/or try not using MKL. > > > > > > I'm looking forward to hear you! > > Best, > > Gang Chen > > Sichuan Univertsity, > School of Mathematics, > Chengdu, China >
