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<div class="moz-cite-prefix">Dear folks,<br>
I did some test with -pc_type gamg with
/src/ksp/ksp/example/tutorial/ex45.c. It is not as good as default
-pc_type when my mesh (Cartisian) is 100*50*50; while it is a
little bit better than the default one when the mesh is
200*100*100. Therefore, I guess this type of pc is good for larger
problem. Is that ture? or is there any rule of thumb for this type
of preconditioner? BTW, I tested it with 8 processes. <br>
<br>
thanks,<br>
Alan<br>
On 9/14/2012 9:38 AM, Mark F. Adams wrote:<br>
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<div>On Sep 14, 2012, at 8:47 AM, Jed Brown <<a
moz-do-not-send="true" href="mailto:jedbrown@mcs.anl.gov">jedbrown@mcs.anl.gov</a>>
wrote:</div>
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<div class="gmail_quote">On Fri, Sep 14, 2012 at 3:47 AM, TAY
wee-beng <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:zonexo@gmail.com" target="_blank">zonexo@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi,<br>
<br>
I need to solve the Poisson eqn on my win7 machine. I'm
currently using BCGS without preconditioner. I can't use
HYPRE since I'm using Fortran and win7. It's rather slow.<br>
<br>
Is there a recommended solver and preconditioner to solve
the Poisson eqn to get me started?<br>
</blockquote>
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<div>What discretization?</div>
<div><br>
</div>
<div>Run with -pc_type gamg to start.</div>
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</blockquote>
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<div>and </div>
<div><br>
</div>
<div>-pc_gamg_agg_nsmooths 1</div>
<div><br>
</div>
<div>(I should make this the default)</div>
<div><br>
</div>
<div>Mark</div>
<br>
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