Please do not focus any attention on ex4f. I just rename my project name to ex4f in order to use the exsiting makefile because I do not know how use the makefile.
At 2013-02-17 02:02:15,"Hui Zhang" <mike.hui.zhang at hotmail.com> wrote: >From my understanding of the bjacobi, it is a block Jacobi method with each >block corresponding to a processor. >What I can not understand is why you get convergence with eight blocks but >divergence with four (fewer) blocks. >Which directory is the program ex4f from? > > >On Feb 16, 2013, at 6:36 PM, w_ang_temp wrote: > >> >> >> I use the two commands in the same project. The first is divergent while the >> second is convergent. >> nohup mpiexec -n 4 ./ex4f -ksp_type bcgs -pc_type bjacobi -ksp_rtol 1.0e-5 >> -ksp_converged_reason >out.txt & >> nohup mpiexec -n 8 ./ex4f -ksp_type bcgs -pc_type bjacobi -ksp_rtol 1.0e-5 >> -ksp_converged_reason >out.txt & >> So what is the reason? >> Thanks. Jim >> >> >> >> >> 2013-02-07 13:16:51?"Matthew Knepley" <knepley at gmail.com> ??? >> >> On Thu, Feb 7, 2013 at 12:11 AM, w_ang_temp <w_ang_temp at 163.com> wrote: >> >> Hello, >> >> I use the same project, but I find that when different number of >> >> processors is choosed, >> >> the convergence is different. For example, when the processors are 4, it >> >> is divergent; when >> >> the processors are 8, it is convergent. >> >> So what is the reason? >> >> >It is likely that your preconditioner changed. >> >> > Matt >> >> >> Thanks. >> >> Jim. >> >> >> >> >> >> -- >> 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 >> >> > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20130217/b0cf7c2b/attachment.html>
