<br>
Here's a thought- why not ask the Hypre guys?<br><br>http://www.llnl.gov/CASC/linear_solvers/team.html<br><br>Cheers<br>Yaron<br><br>
<br>
<table class="readtext" border="0" cellpadding="1" cellspacing="7"><tbody><tr><td bgcolor="black"></td><td>-------Original Message-------<br>
From: Fernando Campos <asdfgf@ig.com.br><br>
Subject: Re: PETSC-Hypre: number of level with boomeramg<br>
Sent: 25 Jan '07 08:26<br>
<br>
Dear Nicolas, <br>
<br>
It is a good question, but I don't know the answer... <br>
Why don't you try to set the maximum levels to a large numbers in order to <br>
see how many levels boomerAMG creates? I believe that it refines the grid up <br>
to the maximum number of levels as you sad. <br>
<br>
I am very interested in both geometric and algebraic multigrids and I also <br>
have a question: "Is it possible to obtain the coarse matrices of each level <br>
using boomerAMG?" <br>
<br>
Best Regards. <br>
<br>
<br>
Em (15:31:40), <a mce_real_href="http://webmail.oak-research.com/compose.php?to=petsc-users@mcs.anl.gov" href="http://webmail.oak-research.com/compose.php?to=petsc-users@mcs.anl.gov" target="_top" style="text-decoration: underline;">petsc-users@mcs.anl.gov</a> escreveu: <br>
<br>
<br>
>Dear Fernando, <br>
> <br>
>Thanks for your reply. <br>
> <br>
>I had notice the value maxlevels given by -ksp_view, but I did not know <br>
>how to change this value. <br>
> <br>
>Still, as the default is 25 levels I think, I have no way to know exactly <br>
>how many levels are used for a given case. <br>
>I can reformulate my question in this way: does boomeramg coarsen the <br>
>"grid" to the coarsest level possible, i.e. 1 cell over the domain, or <br>
>does it stop before that? (grid is not the right term when it comes to <br>
>algebraic multilevel methods, but I can't find any other clear way to <br>
>express it). How can I control the coarsening? <br>
> <br>
>Thinking about it, perhaps boomeramd actually refines the grid up to the <br>
>maximum number of levels...Is it so? <br>
> <br>
>Thanks for your help. <br>
> <br>
>Nicolas <br>
> <br>
>> Nicolas, <br>
>> <br>
>> You should try the option -pc_hypre_boomeramg_max_levels in the line <br>
>> command. In order to see the level's details you can use the PESTc option <br>
>> -ksp_view. <br>
>> <br>
>> Best Regards <br>
>> <br>
>> Fernando. <br>
>> <br>
>> <br>
>> Em (11:15:45), <a mce_real_href="http://webmail.oak-research.com/compose.php?to=petsc-users@mcs.anl.gov" href="http://webmail.oak-research.com/compose.php?to=petsc-users@mcs.anl.gov" target="_top" style="text-decoration: underline;">petsc-users@mcs.anl.gov</a> escreveu: <br>
>> <br>
>> <br>
>>>Hi Petsc users, <br>
>>> <br>
>>>I have a question regarding the use of Hypre and especially Boomeramg. <br>
>>>How can we control the number of levels in the multigrid algortihm? Can <br>
>>> we <br>
>>>chose it, or if not, can we display it in some way? <br>
>>> <br>
>>>Best regards, <br>
>>> <br>
>>>Nicolas. <br>
>>> <br>
>>>-- <br>
>>>Nicolas BATHFIELD <br>
>>>Chalmers University of Technology <br>
>>>Shipping and Marine Technology <br>
>>>phone: +46 (0)31 772 1476 <br>
>>>fax: +46 (0)31 772 3699 <br>
>>> <br>
>>>---------- <br>
>> <br>
>> <br>
>> <br>
> <br>
>-- <br>
>Nicolas BATHFIELD <br>
>Chalmers University of Technology <br>
>Shipping and Marine Technology <br>
>phone: +46 (0)31 772 1476 <br>
>fax: +46 (0)31 772 3699 <br>
> <br>
>---------- <br>
<br>
<br>
</asdfgf@ig.com.br></td></tr></tbody></table>