PETSC-Hypre: number of level with boomeramg

[yaron at oak-research.com]

  Here's a thought- why not ask the Hypre guys?

http://www.llnl.gov/CASC/linear_solvers/team.html

Cheers
Yaron


	-------Original Message-------
  From: Fernando Campos
  Subject: Re: PETSC-Hypre: number of level with boomeramg
  Sent: 25 Jan '07 08:26

  Dear Nicolas,

  It is a good question, but I don't know the answer...
  Why don't you try to set the maximum levels to a large numbers in order
to
  see how many levels boomerAMG creates? I believe that it refines the
grid up
  to the maximum number of levels as you sad.

  I am very interested in both geometric and algebraic multigrids and I
also
  have a question: "Is it possible to obtain the coarse matrices of each
level
  using boomerAMG?"

  Best Regards.


  Em (15:31:40), [LINK:
http://webmail.oak-research.com/compose.php?to=petsc-users@mcs.anl.gov]
petsc-users at mcs.anl.gov escreveu:


  >Dear Fernando,
  >
  >Thanks for your reply.
  >
  >I had notice the value maxlevels given by -ksp_view, but I did not know

  >how to change this value.
  >
  >Still, as the default is 25 levels I think, I have no way to know
exactly
  >how many levels are used for a given case.
  >I can reformulate my question in this way: does boomeramg coarsen the
  >"grid" to the coarsest level possible, i.e. 1 cell over the domain, or
  >does it stop before that? (grid is not the right term when it comes to
  >algebraic multilevel methods, but I can't find any other clear way to
  >express it). How can I control the coarsening?
  >
  >Thinking about it, perhaps boomeramd actually refines the grid up to
the
  >maximum number of levels...Is it so?
  >
  >Thanks for your help.
  >
  >Nicolas
  >
  >> Nicolas,
  >>
  >> You should try the option -pc_hypre_boomeramg_max_levels in the line
  >> command. In order to see the level's details you can use the PESTc
option
  >> -ksp_view.
  >>
  >> Best Regards
  >>
  >> Fernando.
  >>
  >>
  >> Em (11:15:45), [LINK:
http://webmail.oak-research.com/compose.php?to=petsc-users@mcs.anl.gov]
petsc-users at mcs.anl.gov escreveu:
  >>
  >>
  >>>Hi Petsc users,
  >>>
  >>>I have a question regarding the use of Hypre and especially
Boomeramg.
  >>>How can we control the number of levels in the multigrid algortihm?
Can
  >>> we
  >>>chose it, or if not, can we display it in some way?
  >>>
  >>>Best regards,
  >>>
  >>>Nicolas.
  >>>
  >>>--
  >>>Nicolas BATHFIELD
  >>>Chalmers University of Technology
  >>>Shipping and Marine Technology
  >>>phone: +46 (0)31 772 1476
  >>>fax: +46 (0)31 772 3699
  >>>
  >>>----------
  >>
  >>
  >>
  >
  >--
  >Nicolas BATHFIELD
  >Chalmers University of Technology
  >Shipping and Marine Technology
  >phone: +46 (0)31 772 1476
  >fax: +46 (0)31 772 3699
  >
  >----------
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