<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Fri, Mar 21, 2014 at 9:37 AM, Luc Berger-Vergiat <span dir="ltr"><<a href="mailto:lb2653@columbia.edu" target="_blank">lb2653@columbia.edu</a>></span> wrote:<br>
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<div>Is there a way to now what the new
numbering is?<br>
I am assuming that in y example since there are two fields only
the numbers associated with them are 0 and 1 hence I tried:<br>
<blockquote>-fieldsplit_0_fieldsplit_Field_2_fields 1<br>
-fieldsplit_0_fieldsplit_Field_3_fields 0<br></blockquote></div></div></blockquote><div><br></div><div>If its an inner fieldsplit, the numbering for options starts over again</div><div><br></div><div> -fieldsplit_0_fieldsplit_Field_0_fields 1<br>
</div><div> -fieldsplit_0_fieldsplit_Field_1_fields 0<br></div><div><br></div><div> Thanks,</div><div><br></div><div> Matt</div><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">
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which did not work. As mentioned earlier, the following does not
work either:<br>
<blockquote>-fieldsplit_0_fieldsplit_Field_2_fields 3<br>
-fieldsplit_0_fieldsplit_Field_3_fields 2<br>
</blockquote>
and without too much expectation I also passed the following<br>
<blockquote>-fieldsplit_0_fieldsplit_Field_2_fields Field_3<br>
-fieldsplit_0_fieldsplit_Field_3_fields Field_2</blockquote>
to no avail.<br>
<br>
By the way I attached the output from -ksp_view in case I might be
doing something wrong?<br>
<br>
<pre cols="72">Best,
Luc</pre>
On 03/20/2014 09:01 PM, Matthew Knepley wrote:<br>
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<div class="gmail_quote">On Thu, Mar 20, 2014 at 6:20 PM, Luc
Berger-Vergiat <span dir="ltr"><<a href="mailto:lb2653@columbia.edu" target="_blank">lb2653@columbia.edu</a>></span>
wrote:<br>
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<div bgcolor="#FFFFFF" text="#000000"> Hi all,<br>
I am solving a four field problem using two Schur
complements. Here are the arguments that I usually pass
to PETSc to do it:<br>
<blockquote>-ksp_type gmres -pc_type fieldsplit
-pc_fieldsplit_type schur
-pc_fieldsplit_schur_factorization_type full
-pc_fieldsplit_schur_precondition selfp
-pc_fieldsplit_0_fields 2,3 -pc_fieldsplit_1_fields
0,1 -fieldsplit_0_ksp_type preonly
-fieldsplit_0_pc_type fieldsplit
-fieldsplit_0_pc_fieldsplit_type schur
-fieldsplit_0_pc_fieldsplit_schur_factorization_type
full -fieldsplit_0_pc_fieldsplit_schur_precondition
selfp -fieldsplit_0_fieldsplit_Field_2_fields 2
-fieldsplit_0_fieldsplit_Field_3_fields 3
-fieldsplit_0_fieldsplit_Field_2_ksp_type preonly
-fieldsplit_0_fieldsplit_Field_2_pc_type ilu
-fieldsplit_0_fieldsplit_Field_3_ksp_type preonly
-fieldsplit_0_fieldsplit_Field_3_pc_type jacobi
-fieldsplit_1_ksp_type preonly -fieldsplit_1_pc_type
lu -malloc_log mlog -log_summary time.log<br>
</blockquote>
One issue with this is that when I change
-fieldsplit_0_fieldsplit_Field_2_fields 2 to
-fieldsplit_0_fieldsplit_Field_2_fields 3 it is
ineffective, as if PETSc automatically assign IS 2 to
Field 2 even though it is not what I want.<br>
Is there a way to pass the arguments correctly so that
PETSc goes about switching the IS set of
-fieldsplit_0_fieldsplit_Field_2 and
-fieldsplit_0_fieldsplit_Field_3?<br>
This is crucial to me since I am using the selfp option
and the matrix associated to IS 3 is diagonal. By
assigning the fields correctly I can get an exact Schur
preconditioner and hence very fast convergence. Right
now my convergence is not optimal because of this.<br>
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<div><br>
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<div>I believe the inner Schur field statements should not
be using the original numbering, but the inner numbering,
after they have been reordered.</div>
<div><br>
</div>
<div> Matt</div>
<div> </div>
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<div bgcolor="#FFFFFF" text="#000000">Thanks!<br>
<br>
Best,<br>
Luc<br>
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<br>
<br clear="all"><span class=""><font color="#888888">
<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
</font></span></div>
</div>
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<br>
</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
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