<div dir="ltr">This was fixed on June 18 (Stephen Kramer):<div><br></div><div><span class="im" style="font-size:12.8000001907349px"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><br>Can you please test this and see if works, without your fix?<br><br> 'git fetch; git checkout mark/<span class="">gamg</span>-crs',<br></blockquote><br></span><span style="font-size:12.8000001907349px">Great! That fixes everything for me: it uses KSP+</span><span class="" style="font-size:12.8000001907349px;background-color:rgb(255,255,255)">PREONLY</span><span style="font-size:12.8000001907349px"> for mg_coarse by default again and I can also override it with -mg_coarse_ksp_type</span><br style="font-size:12.8000001907349px"><br style="font-size:12.8000001907349px"><span style="font-size:12.8000001907349px">Thanks a lot for fixing this</span><br style="font-size:12.8000001907349px"><span style="font-size:12.8000001907349px">Cheers</span><br></div><div><span style="font-size:12.8000001907349px"><br></span></div><div><span style="font-size:12.8000001907349px">This was soon merged to master & next. In src/ksp/pc/impls/mg/mg.c we have:</span></div><div><span style="font-size:12.8000001907349px"><br></span></div><div><div style=""><span style="font-size:12.8000001907349px"> ierr = PetscObjectTypeCompare((PetscObject)cpc,PCLU,&lu);CHKERRQ(ierr);</span></div><div style=""><span style="font-size:12.8000001907349px"> ierr = PetscObjectTypeCompare((PetscObject)cpc,PCREDUNDANT,&redundant);CHKERRQ(ierr);</span></div><div style=""><span style="font-size:12.8000001907349px"> ierr = PetscObjectTypeCompare((PetscObject)cpc,PCCHOLESKY,&cholesky);CHKERRQ(ierr);</span></div><div style=""><span style="font-size:12.8000001907349px"> ierr = PetscObjectTypeCompare((PetscObject)cpc,PCSVD,&svd);CHKERRQ(ierr);</span></div><div style=""><span style="font-size:12.8000001907349px"> if (!lu && !redundant && !cholesky && !svd && !bjaclu) {</span></div><div style=""><span style="font-size:12.8000001907349px"> ierr = KSPSetType(mglevels[0]->smoothd,KSPGMRES);CHKERRQ(ierr);</span></div><div style=""><span style="font-size:12.8000001907349px"> }</span></div></div><div><span style="font-size:12.8000001907349px"><br></span></div><div><span style="font-size:12.8000001907349px">Perhaps our logic is failing here? This is the only place where GMRES spontaneously appears. We should really remove this altogether.</span></div><div><span style="font-size:12.8000001907349px"><br></span></div><div><span style="font-size:12.8000001907349px"><br></span></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Sat, Jul 18, 2015 at 11:40 PM, Matthew Knepley <span dir="ltr"><<a href="mailto:knepley@gmail.com" target="_blank">knepley@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Sat, Jul 18, 2015 at 10:31 PM, Michele Rosso <span dir="ltr"><<a href="mailto:mrosso@uci.edu" target="_blank">mrosso@uci.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><u></u>
<div>
Matt,<br>
<br>
please find the log_summary attached.<br></div></blockquote><div><br></div><div>Okay, it is running master. Barry, where should he look in the code to see why its still changing,</div><div>meaning what changeset fixed this?</div><div><br></div><div> Thanks,</div><div><br></div><div> Matt</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div>
Michele<div><div class="h5"><br>
<br>
On Sat, 2015-07-18 at 21:56 -0500, Matthew Knepley wrote:
<blockquote type="CITE">
On Sat, Jul 18, 2015 at 9:53 PM, Michele Rosso <<a href="mailto:mrosso@uci.edu" target="_blank">mrosso@uci.edu</a>> wrote:
</blockquote>
<blockquote type="CITE">
<blockquote>
Barry,<br>
<br>
I tried the master branch of PETSc as you suggested and unfortunately the problem with KSP being set to GMRES on the coarse level when using "-mg_coarse_ksp_type preonly" is still there. I attached the output from ksp view and the options stack.<br>
Am I missing something?<br>
<br>
</blockquote>
</blockquote>
<blockquote type="CITE">
<br>
<br>
</blockquote>
<blockquote type="CITE">
If you show output from -log_summary we can make sure you are running the version we expect.
</blockquote>
<blockquote type="CITE">
<br>
<br>
</blockquote>
<blockquote type="CITE">
Thanks,
</blockquote>
<blockquote type="CITE">
<br>
<br>
</blockquote>
<blockquote type="CITE">
Matt
</blockquote>
<blockquote type="CITE">
</blockquote>
<blockquote type="CITE">
<blockquote>
Thanks,<br>
Michele<br>
<br>
<br>
On Thu, 2015-07-16 at 17:30 -0500, Barry Smith wrote:
<blockquote type="CITE">
<pre> Michel,
This is a very annoying feature that has been fixed in master <a href="http://www.mcs.anl.gov/petsc/developers/index.html" target="_blank">http://www.mcs.anl.gov/petsc/developers/index.html</a> I would like to have changed it in maint but Jed would have a shit-fit :-) since it changes behavior.
Barry
<font color="#737373">> On Jul 16, 2015, at 4:53 PM, Michele Rosso <<a href="mailto:mrosso@uci.edu" target="_blank">mrosso@uci.edu</a>> wrote:</font>
<font color="#737373">> </font>
<font color="#737373">> Hi,</font>
<font color="#737373">> </font>
<font color="#737373">> I am performing a series of solves inside a loop. The matrix for each solve changes but not enough to justify a rebuilt of the PC at each solve.</font>
<font color="#737373">> Therefore I am using KSPSetReusePreconditioner to avoid rebuilding unless necessary. The solver is CG + MG with a custom PC at the coarse level.</font>
<font color="#737373">> If KSP is not updated each time, everything works as it is supposed to. </font>
<font color="#737373">> When instead I allow the default PETSc behavior, i.e. updating PC every time the matrix changes, the coarse level KSP , initially set to PREONLY, is changed into GMRES </font>
<font color="#737373">> after the first solve. I am not sure where the problem lies (my PC or PETSc), so I would like to have your opinion on this.</font>
<font color="#737373">> I attached the ksp_view for the 2 successive solve and the options stack.</font>
<font color="#737373">> </font>
<font color="#737373">> Thanks for your help,</font>
<font color="#737373">> Michel</font>
<font color="#737373">> </font>
<font color="#737373">> </font>
<font color="#737373">> </font>
<font color="#737373">> <ksp_view.txt><petsc_options.txt></font>
</pre>
</blockquote>
<br>
<br>
</blockquote>
</blockquote>
<blockquote type="CITE">
<br>
<br>
</blockquote>
<blockquote type="CITE">
<br><span><font color="#888888">
<br>
</font></span></blockquote><span><font color="#888888">
<blockquote type="CITE">
--
</blockquote>
<blockquote type="CITE">
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
</blockquote>
<br>
</font></span></div></div></div>
</blockquote></div><div><div class="h5"><br><br clear="all"><div><br></div>-- <br><div>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</div>
</div></div></div></div>
</blockquote></div><br></div>