On Thu, Aug 9, 2012 at 9:21 AM, Sanjay Govindjee <span dir="ltr"><<a href="mailto:s_g@berkeley.edu" target="_blank">s_g@berkeley.edu</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Colin,<br>
I you block the equations in FEAP, then the restrained BCs are 'included' in assembled PETSc matrix (these dofs have rows that are zero modulo a value of unity on the diagonal and the restrained value on the right-hand side).<br>
</blockquote><div><br></div><div>However, this is not necessary with the DM interface.</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">
-sg<br>
<br>
On 8/9/12 8:41 AM, Colin McAuliffe wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
>From what I can gather from the petsc-dev source it looks like the commands in 4) will then generate the splits using strided blocks. The problem with that is the fortran code I am using (FEAP) uses petsc to assemble and solve the linear problem within its own nonlinear and time stepping schemes. The linear problem that petsc solves already has boundary conditions applied to it so petsc only sees the active (unrestrained) equations. So then in general fields can't be extracted from the active equations using strided blocks and I am stuck with generating the index sets defining the splits on my own. Will it still be possible to make use of the new DM functions in this case?<br>
<br>
FEAP website:<br>
<a href="http://www.ce.berkeley.edu/projects/feap/" target="_blank">http://www.ce.berkeley.edu/<u></u>projects/feap/</a><br>
<br>
Colin<br>
<br>
<br>
Quoting Matthew Knepley <<a href="mailto:knepley@gmail.com" target="_blank">knepley@gmail.com</a>>:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
On Wed, Aug 8, 2012 at 10:51 PM, Matthew Knepley <<a href="mailto:knepley@gmail.com" target="_blank">knepley@gmail.com</a>> wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
On Wed, Aug 8, 2012 at 10:23 PM, Colin McAuliffe <<a href="mailto:cjm2176@columbia.edu" target="_blank">cjm2176@columbia.edu</a>>wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Thanks all, regarding use of DM in 3.3, is the procedure now to create<br>
the fields with PCFieldSplitSetIS and then use DMCreateFieldDecompositionDM<br>
to create a new DM based from the new fields and the DM for the original<br>
problem?<br>
<br>
</blockquote>
<br>
1) Use petsc-dev<br>
<br>
2) PCFieldSplitSetIS() is independent. This allows you to define splits<br>
however you want, but then recursive gets harder<br>
<br>
3) In 3.3., it uses DMCreateFieldDecompositionDM() to split all fields<br>
apart at once<br>
<br>
4) In petsc-dev, it uses DMCreateSubDM() which can split off any<br>
combination of fields, which from the command line is something like<br>
<br>
-pc_fieldsplit_0_fields 2,0 -pc_fieldsplit_1_fields 1,3<br>
<br>
</blockquote>
<br>
I should have shown recursive:<br>
<br>
-fieldsplit_0_pc_type fieldsplit<br>
<br>
will split 2,0 into two blocks.<br>
<br>
Matt<br>
<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Matt<br>
<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Colin<br>
<br>
-- <br>
Colin McAuliffe<br>
PhD Candidate<br>
Columbia University<br>
Department of Civil Engineering and Engineering Mechanics<br>
<br>
</blockquote>
<br>
<br>
<br>
-- <br>
What most experimenters take for granted before they begin their<br>
experiments is infinitely more interesting than any results to which their<br>
experiments lead.<br>
-- Norbert Wiener<br>
<br>
</blockquote>
<br>
<br>
<br>
-- <br>
What most experimenters take for granted before they begin their<br>
experiments is infinitely more interesting than any results to which their<br>
experiments lead.<br>
-- Norbert Wiener<br>
<br>
</blockquote>
<br>
<br>
<br>
</blockquote>
<br>
-- <br>
------------------------------<u></u>-----------------<br>
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<br>
</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<br>