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), 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), 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 > >----------
