Just pass it as a command line option. It gives profiling output in PetscFinalize().
On Sat, Nov 3, 2012 at 10:52 AM, w_ang_temp <w_ang_temp at 163.com> wrote: > Is there something that need attention when setting up PETSc? The > -log_summary > is no use in my system. > > > >At 2012-11-03 23:31:52,"Jed Brown" <jedbrown at mcs.anl.gov> wrote: > > >1. *Always* send -log_summary when asking about performance. > >2. AMG setup costs more, the solve should be faster, especially for large > problems. > >3. 30k degrees of freedom is not large. > > > >>On Sat, Nov 3, 2012 at 10:27 AM, w_ang_temp <w_ang_temp at 163.com> wrote: > >> >>Hello, >> >> I have tried AMG, but there are some problems. I use the command: >> >> mpiexec -n 4 ./ex4f -ksp_type gmres -pc_type gamg >> -pc_gamg_agg_nsmooths 1 -ksp_gmres_restart 170 -ksp_rtol 1.0e-15 >> ->>ksp_converged_reason. >> >> The matrix has a size of 30000. However, compared with -pc_type asm, >> >>the amg need more time:asm needs 4.9s, amg needs 13.7s. I did several >> tests >> >>and got the same conclusion. When it begins, the screen shows the >> information: >> >>[0]PCSetData_AGG bs=1 MM=7601. I do not know the meaning. And if there >> is some >> >>parameters that affect the performance of AMG? >> >> Besides, I want to confirm a conception. In my view, AMG itself can >> be a solver >> >>like gmres. It can also be used as a preconditioner like jacobi and is >> used by combining >> >>with other solver. Is it right? If it is right, how use AMG solver? >> >> My codes are attached. >> >> Thanks. >> >> Jim >> >> >> >> >At 2012-11-01 22:00:28,"Jed Brown" <jedbrown at mcs.anl.gov> wrote: >> >> >Yes, it's faster to understand this error message than to have >> "mysteriously slow performance". >> >> >** Preallocation routines now automatically set >> MAT_NEW_NONZERO_ALLOCATION_ERR, if you intentionally preallocate less than >> necessary then *>*use >> MatSetOption(mat,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_FALSE) to disable the >> error generation. >> * >> >http://www.mcs.anl.gov/petsc/documentation/changes/33.html >> >> >On Thu, Nov 1, 2012 at 8:57 AM, w_ang_temp <w_ang_temp at 163.com> wrote: >> >>> >Do you mean that the two versions have a different in this point? If I >>> use the new version, I have to >>> >make some modifications on my codes? >>> >> >> >> >> > > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20121103/5a087a4a/attachment.html>
