On Nov 9, 2012, at 10:05 AM, w_ang_temp <w_ang_temp at 163.com> wrote:
> Hello,Jed > > Sorry again for the interruption. > > As you said, if I want to use Algebraic multigrid, I can just use > '-pc_type gamg > -pc_gamg_agg_nsmooths 1' in the command line. I think there are many other > -pc_gamg_XXX > parameters. How can I find all the -pc_gamg_XXX? -help > > Besides, I want to know more about AMG. Are there any details from PETSc, > like manual, > documentaion, FAQ, etc? I would recommend the book "Multigrid" by Trottenberg, et al, and the classic "Multigrid Tutorial" is good to look at also. > Also, from the above post, I want to know that if AMG can not be used in > 3.2 by command > line option, because now I have to use 3.3 for using AMG. I just donot want > to change my > version 3.2 now. You can use 3.2 if you like (free country) but this code was developed a lot between 3.2 and 3.3. I forget what was in 3.2 exactly. If you have a straight forward problem and 3.2 works then its is probably OK for your current purposes. > > I am major in Civil Engineering and not good at math and programming. So > please > forgive my weakness. > Thanks. > Jim > > > > > > > >At 2012-10-28 21:17:00,"Jed Brown" <jedbrown at mcs.anl.gov> wrote: > >Algebraic multigrid can be used directly, -pc_type gamg > >-pc_gamg_agg_nsmooths 1. Geometric either required that you use the PCMG > >interface to set >interpolation (and provide a coarse operator for > >non-Galerkin) or use a DM that provides coarsening capability. > > >What kind of problem are you solving? > > >>On Oct 28, 2012 6:09 AM, "w_ang_temp" <w_ang_temp at 163.com> wrote: > >>Hello, > >> I want to use the multigrid as a preconditioner. The introduction about > it in the manual is little. > >>So are there some typical examples or details about multigrid? Is it used > >>just like other preconditioners > >>like jacobi, sor, which can be simply used in the cammand line options? > >> Thanks. > > > Jim > > > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20121109/0d0593e7/attachment.html>
