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<p>Matt,</p>
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<p>Yes. I would like to try. Where should I start? </p>
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<div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt" color="#000000" face="Calibri, sans-serif"><b>From:</b> Matthew Knepley <knepley@gmail.com><br>
<b>Sent:</b> Thursday, October 15, 2015 3:43 PM<br>
<b>To:</b> Barry Smith<br>
<b>Cc:</b> Xiao, Jianjun (IKET); petsc-users@mcs.anl.gov<br>
<b>Subject:</b> Re: [petsc-users] Load balancing problem with DMDA</font>
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<div class="gmail_quote">On Wed, Oct 14, 2015 at 3:32 PM, Barry Smith <span dir="ltr">
<<a href="mailto:bsmith@mcs.anl.gov" target="_blank">bsmith@mcs.anl.gov</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex; border-left:1px #ccc solid; padding-left:1ex">
<span class=""><br>
> On Oct 14, 2015, at 3:11 PM, Xiao, Jianjun (IKET) <<a href="mailto:jianjun.xiao@kit.edu">jianjun.xiao@kit.edu</a>> wrote:<br>
><br>
> Hello,<br>
><br>
> We have a finite volume code with structured grid. We use the DMDA data structure.<br>
><br>
> Now we have the load balancing problem as shown in the attached picture. The domain is decomposed into 4 partitions. The sub-domain in black (proc 2) is solid which is of no interest. We would like to calculate only the fluid part in proc 1, 3 and 4 which
means the resource in proc 2 is wasted. Does DMDA now support multi-block with communication between blocks? I mean I build block 1 and assign to proc1, block 2 to proc 3 and block 3 to proc 4. So the solid sub-domain does not exist. Any suggestion?<br>
<br>
</span>No<br>
<span class=""><br>
><br>
> Or I have to do it using DMPLEX? Since data structure of the whole code is based on DMDA, is there any "simple way" to switch from DMDA to DMPLEX without changing the loop structure in the code?<br>
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</span> No<br>
<br>
DMDA is for simple structured grids.</blockquote>
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<div>Using Plex would be some work since no one has ever used it to do FD. In fact, now I think the way to do this</div>
<div>is to only represent the vertices and edges. I would help you if you want to experiment with that.</div>
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<div> Thanks,</div>
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<div> Matt</div>
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<blockquote class="gmail_quote" style="margin:0 0 0 .8ex; border-left:1px #ccc solid; padding-left:1ex">
<span class=""><br>
><br>
> Thank you.<br>
><br>
> Best regards<br>
> Jianjun<br>
</span>> <pic.JPG><br>
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-- <br>
<div class="gmail_signature">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>
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