<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Wed, Jul 16, 2014 at 4:25 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"><div class="">On Wed, Jul 16, 2014 at 4:22 PM, Sun, Hui <span dir="ltr"><<a href="mailto:hus003@ucsd.edu" target="_blank">hus003@ucsd.edu</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div>
<div style="direction:ltr;font-family:Tahoma;color:#000000;font-size:10pt">Thank you Matt for answering, however even with that I don't think it works. For example, the command
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<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
./ex70 -nx 32 -ny 48 -fieldsplit_1_type jacobi</p></div></div></div></blockquote><div><br></div></div><div>You have mistyped. Look carefully at my last message:</div><div><br></div><div> -fieldsplit_1_pc_type jacobi</div>
</div></div></div></blockquote><div><br></div><div>I also want to note that you can see all the available options with -help. It does produce</div><div>a lot of output, but you can segregate it by prefix ("fieldsplit_1_"). You can also see the</div>
<div>prefix of each solver component using -ksp_view.</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 dir="ltr"><div class="gmail_extra">
<div class="gmail_quote"><div> Matt</div><div><div class="h5"><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div style="direction:ltr;font-family:Tahoma;color:#000000;font-size:10pt">
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<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
<span style="font-family:Tahoma;font-size:13px">gives me the following output</span></p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
<span style="font-family:Tahoma;font-size:13px"><br>
</span></p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
residual u = 2.6315e-05</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
residual p = 0.000229872</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
residual [u,p] = 0.000231373</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
discretization error u = 0.00633503</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
discretization error p = 0.121534</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
discretization error [u,p] = 0.121699</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
WARNING! There are options you set that were not used!</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
WARNING! could be spelling mistake, etc!</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
Option left: name:-fieldsplit_1_type value: jacobi</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
<br>
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<p style="margin-right:0px;margin-left:0px">Furthermore, if I look into the possible options with keyword fieldsplit involved by the command:</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
<br>
</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
./ex70 -help | grep -A5 fieldsplit</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
<span style="font-family:Tahoma;font-size:13px"><br>
</span></p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
<span style="font-family:Tahoma;font-size:13px">I get this output:</span></p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
<span style="font-family:Tahoma;font-size:13px"><br>
</span></p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
eisenstat ilu icc cholesky asm gasm ksp composite redundant nn mat fieldsplit galerkin exotic hmpi asa cp lsc redistribute svd gamg tfs (PCSetType)</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
-pc_use_amat: <FALSE> use Amat (instead of Pmat) to define preconditioner in nested inner solves (PCSetUseAmat)</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
Krylov Method (KSP) options -------------------------------------------------</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
-ksp_type <gmres>: Krylov method (one of) cg groppcg pipecg cgne nash stcg gltr richardson</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
chebyshev gmres tcqmr bcgs ibcgs fbcgs fbcgsr bcgsl cgs tfqmr cr pipecr lsqr preonly qcg bicg fgmres minres symmlq lgmres lcd gcr pgmres specest dgmres (KSPSetType)</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
-ksp_max_it <10000>: Maximum number of iterations (KSPSetTolerances)</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
<br>
</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
<span style="font-family:Tahoma;font-size:13px">So I don't see any option that's similar to -fieldsplit_1_type. </span></p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
<span style="font-family:Tahoma;font-size:13px"><br>
</span></p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
<span style="font-family:Tahoma;font-size:13px">Hui</span></p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
<span style="font-family:Tahoma;font-size:13px"><br>
</span></p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">
<br>
</p>
<div style="font-family:Times New Roman;color:#000000;font-size:16px">
<hr>
<div style="direction:ltr"><font face="Tahoma" color="#000000"><b>From:</b> Matthew Knepley [<a href="mailto:knepley@gmail.com" target="_blank">knepley@gmail.com</a>]<br>
<b>Sent:</b> Wednesday, July 16, 2014 2:16 PM<br>
<b>To:</b> Sun, Hui<br>
<b>Cc:</b> <a href="mailto:petsc-users@mcs.anl.gov" target="_blank">petsc-users@mcs.anl.gov</a><br>
<b>Subject:</b> Re: [petsc-users] why a certain option cannot be used<br>
</font><br>
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<div class="gmail_extra">
<div class="gmail_quote">On Wed, Jul 16, 2014 at 4:09 PM, Sun, Hui <span dir="ltr">
<<a href="mailto:hus003@ucsd.edu" target="_blank">hus003@ucsd.edu</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<div style="direction:ltr;font-family:Tahoma;color:#000000;font-size:10pt">I want to solve Stokes equation using user defined schur complement preconditioner. So I'm reading and testing snes/examples/tutorial/ex55.c, and ex70.c. In these examples, there
are comments about the usage, for example:
<div><span style="color:rgb(215,57,30);font-family:Menlo;font-size:11px"><br>
</span></div>
<div><span style="color:rgb(215,57,30);font-family:Menlo;font-size:11px">mpiexec -n 2 ./stokes -nx 32 -ny 48 -fieldsplit_1_user_pc. </span>
<div><span style="font-size:10pt"><br>
</span></div>
<div><span style="font-size:10pt">However the option </span><span style="color:rgb(215,57,30);font-family:Menlo;font-size:11px">-fieldsplit_1_user_pc</span><span style="font-size:10pt"> is not recognized by the executable. The output of the above command
is:</span></div>
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<div>This ("user_pc") is just a mnemonic. What it means is that you can use any PC in this slot. What he should have written is</div>
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<div> -fieldsplit_1_pc_type <user pc></div>
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<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">
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<div style="direction:ltr;font-family:Tahoma;color:#000000;font-size:10pt">
<div>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo"> residual u = 2.6315e-05</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo"> residual p = 0.000229872</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo"> residual [u,p] = 0.000231373</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo"> discretization error u = 0.00633503</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo"> discretization error p = 0.121534</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo"> discretization error [u,p] = 0.121699</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">WARNING! There are options you set that were not used!</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">WARNING! could be spelling mistake, etc!</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo">Option left: name:-fieldsplit_1_user_pc (no value)</p>
<p style="margin-right:0px;margin-left:0px;font-size:11px;font-family:Menlo"><br>
</p>
<p style="margin-right:0px;margin-left:0px">I'm wondering what's going on. Is that because I need some specific options during my configuring of the package? By the way, the version of PETSc I'm using is 3.4.4. </p>
<p style="margin-right:0px;margin-left:0px"><br>
</p>
<p style="margin-right:0px;margin-left:0px">Best,</p>
<p style="margin-right:0px;margin-left:0px">Hui</p><span><font color="#888888">
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</font></span></blockquote><span><font color="#888888">
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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 </font></span></div>
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</blockquote></div></div></div><div><div class="h5"><br><br clear="all"><div><br></div>-- <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
</div></div></div></div>
</blockquote></div><br><br clear="all"><div><br></div>-- <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
</div></div>