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<div class="moz-cite-prefix">On 30/10/2012 1:44 PM, Matthew Knepley
wrote:<br>
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<blockquote
cite="mid:CAMYG4G=_4Ndr6GHZgG+fODwFyJWeXhcDZPZXsdQJFDjPwNpBYg@mail.gmail.com"
type="cite">On Tue, Oct 30, 2012 at 7:41 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>
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<div>On 28/10/2012 2:17 PM, Jed Brown wrote:<br>
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<blockquote type="cite">
<p>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.</p>
<p>What kind of problem are you solving?</p>
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<br>
Hi, <br>
<br>
May I know if there is an example which explains using the
geometric MG, either using PCMG or DM?<br>
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<div><br>
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<div>SNES ex5 and ex19 both use MG.</div>
<div><br>
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<div> Matt</div>
</div>
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Are there examples which uses ksp and geometric MG? I want to solve
a Poisson eqn which has been discretized to give a sys of linear
eqns. <br>
<br>
I also found this thread :<br>
<br>
<a class="moz-txt-link-freetext" href="http://lists.mcs.anl.gov/pipermail/petsc-users/2012-August/015073.html">http://lists.mcs.anl.gov/pipermail/petsc-users/2012-August/015073.html</a><br>
<br>
Is it using geometric MG to solve a sys of linear eqns?
<blockquote
cite="mid:CAMYG4G=_4Ndr6GHZgG+fODwFyJWeXhcDZPZXsdQJFDjPwNpBYg@mail.gmail.com"
type="cite">
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<pre cols="72">Yours sincerely,
TAY wee-beng</pre>
<br>
<blockquote type="cite">
<div class="gmail_quote">On Oct 28, 2012 6:09 AM,
"w_ang_temp" <<a moz-do-not-send="true"
href="mailto:w_ang_temp@163.com" target="_blank">w_ang_temp@163.com</a>>
wrote:<br type="attribution">
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style="line-height:1.7;font-size:14px;font-family:arial">
<div>Hello,</div>
<div> I want to use the multigrid as a
preconditioner. The introduction about it in the
manual is little.</div>
<div>So are there some typical examples or details
about multigrid? Is it used just like other
preconditioners</div>
<div>like jacobi, sor, which can be simply used in
the cammand line options?</div>
<div> Thanks.</div>
<div>
Jim</div>
</div>
<br>
<br>
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-- <br>
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to
which their experiments lead.<br>
-- Norbert Wiener<br>
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