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    Thomas,<br>
    <br>
      It looks like you are asking FEAP to solve the equations multiples
    times.  Perhaps you have a nonlinear problem with a Newton loop?  <br>
    <br>
      This is not a fair comparison. Edit your run script to only
    perform 1 (one) solve "tang,,1" (No Newton loops), then compare.<br>
    <br>
    -sg<br>
    <br>
    <div class="moz-cite-prefix">On 1/27/14 9:48 AM, Thomas Gross wrote:<br>
    </div>
    <blockquote
      cite="mid:DC5026D6-3664-4EC0-96E0-30C981029EE7@ilsb.tuwien.ac.at"
      type="cite">
      <pre wrap="">I ran it with:
-ksp_type cg -pc_type gamg -pc_gamg_type agg -log_summary -ksp_monitor -ksp_view -options_left -mg_levels_ksp_max_it 1 > GAMG_log_max_it.txt
and
-ksp_type cg -pc_type gamg -pc_gamg_type agg -log_summary -ksp_monitor -ksp_view -options_left -mg_levels_ksp_type richardson -mg_levels_pc_type sor > GAMG_log_Rich.txt
(Log files attached)

However, the solution time did not decrease and I still needed to call KSPSolve 3 times although I had -mg_levels_ksp_max_it 1. 

Best
Thomas

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      <br>
      <pre wrap="">

On Jan 27, 2014, at 5:53 PM, Jed Brown <a class="moz-txt-link-rfc2396E" href="mailto:jed@jedbrown.org"><jed@jedbrown.org></a> wrote:

</pre>
      <blockquote type="cite">
        <pre wrap="">Thomas Gross <a class="moz-txt-link-rfc2396E" href="mailto:tgross@ilsb.tuwien.ac.at"><tgross@ilsb.tuwien.ac.at></a> writes:

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        <blockquote type="cite">
          <pre wrap="">Please find enclosed the log summary for the runs.

I used the following options for Prometheus and GAMG:
Prometheus:
-ksp_type cg -pc_type prometheus -log_summary -ksp_monitor -ksp_view -aggmg_smooths 1 -options_left
GAMG:
-ksp_type cg -pc_type gamg -pc_gamg_type agg -pc_gamg_agg_nsmooths 1 -log_summary -ksp_monitor -ksp_view -options_left
</pre>
        </blockquote>
        <pre wrap="">
This is a pretty small problem, but switch back to a single smoothing
iteration -mg_levels_ksp_max_it 1.  An alternative is
-mg_levels_ksp_type richardson -mg_levels_pc_type sor.

Note that you are calling KSPSolve 3 times with GAMG, but only once with
Prometheus.
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      <pre wrap="">
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    <br>
    <pre class="moz-signature" cols="72">-- 
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