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<div class="moz-cite-prefix">Hi all,<br>
<br>
in my opinion, this correspondence should not be stored since it
can be deduced straightforwardly from the principal vertices. In
general, I think we should limit the data in the file without
incurring a huge cost to reconstruct missing information or even
risk ambiguities - both are applicable to periodic
transformations; storing only principal vertices then seems the
best compromise. The compacity of this section is important, since
periodicity information is very difficult to partition, which
means that this section should be as light as possible as it is
duplicated for all partitions in case we store one file per
partition - the latter option is important for very large meshes.<br>
<br>
The ho point correspondence is stored in gmsh internal
datastructures though, since it is required for ensuring continued
periodicity when optimizing a high order mesh - we guarantee that
the high order nodes also satisfy exactly the periodicity. In
principle, adding these points should therefore not require a big
effort.<br>
<br>
This being said, there is currently an issue with reading periodic
meshes : gmsh seems to displace the nodes by twice the periodicity
transformation.<br>
<br>
Best,<br>
<br>
Koen<br>
<br>
<br>
On 07/26/2018 07:34 PM, Christophe Geuzaine wrote:<br>
</div>
<blockquote type="cite"
cite="mid:79348EE0-6E6A-425F-B725-3FF31D9F3D8B@uliege.be">
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<br class="">
<div><br class="">
<blockquote type="cite" class="">
<div class="">On 26 Jul 2018, at 08:24, Nan Li <<a
href="mailto:linan88433189@gmail.com" class=""
moz-do-not-send="true">linan88433189@gmail.com</a>>
wrote:</div>
<br class="Apple-interchange-newline">
<div class="">
<div dir="ltr" class="">
Hello everyone,<br class="">
<br class="">
I am trying to mesh a cross-cavity with high order
tetrahedron element (tetrahedron 10) and apply periodic
boundary condition in x direction and y direction. As the
periodic boundary condition has nothing to do with the
cavity, you can consider the cross-cavity as a cube. <br
class="">
<br class="">
I have used 'periodic surfaces' and find the mesh of the
two opposite surface is identical. So far so good. Then
when I look into the .msh file and try to extract the
point pairs in $Periodic $EndPeriodic, I find that only
the nodes on the vertex of triangle are listed there. The
internal nodes for each edge are not listed. <br class="">
<br class="">
Does anyone have successfully extract the periodic pairs
of internal nodes of each edge ?<br class="">
<br class="">
</div>
</div>
</blockquote>
<div><br class="">
</div>
<div>Indeed we only keep track of the main vertices in the
Periodic section. Once you have those you can get the element
correspondance and match the high-order ones.</div>
<div><br class="">
</div>
<div>@Koen, Amaury - should we also add the high-order vertices
in the correspondance tables ?</div>
<div><br class="">
</div>
<div>Christophe</div>
<div><br class="">
</div>
<br class="">
<blockquote type="cite" class="">
<div class="">
<div dir="ltr" class="">Thanks. <br class="">
<br class="">
Nan LI</div>
<span id="cid:7D724FE4-5E28-4A11-AD81-921B01F1CF39@home"><cross_cavity.geo></span>_______________________________________________<br
class="">
gmsh mailing list<br class="">
<a href="mailto:gmsh@onelab.info" class=""
moz-do-not-send="true">gmsh@onelab.info</a><br class="">
<a class="moz-txt-link-freetext" href="http://onelab.info/mailman/listinfo/gmsh">http://onelab.info/mailman/listinfo/gmsh</a><br class="">
</div>
</blockquote>
</div>
<br class="">
<div class="">
<div dir="auto" style="word-wrap: break-word; -webkit-nbsp-mode:
space; line-break: after-white-space;" class="">
<div style="color: rgb(0, 0, 0); font-family: Helvetica;
font-size: 12px; font-style: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
text-align: start; text-indent: 0px; text-transform: none;
white-space: normal; word-spacing: 0px;
-webkit-text-stroke-width: 0px;">— </div>
<div style="color: rgb(0, 0, 0); font-family: Helvetica;
font-size: 12px; font-style: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
text-align: start; text-indent: 0px; text-transform: none;
white-space: normal; word-spacing: 0px;
-webkit-text-stroke-width: 0px;">Prof. Christophe Geuzaine<br
class="">
University of Liege, Electrical Engineering and Computer
Science <br class="">
<a href="http://www.montefiore.ulg.ac.be/%7Egeuzaine"
class="" moz-do-not-send="true">http://www.montefiore.ulg.ac.be/~geuzaine</a><br
class="">
<br class="">
Free
software: <a class="moz-txt-link-freetext" href="http://gmsh.info">http://gmsh.info</a> | <a class="moz-txt-link-freetext" href="http://getdp.info">http://getdp.info</a> | <a class="moz-txt-link-freetext" href="http://onelab.info">http://onelab.info</a></div>
</div>
</div>
<br class="">
</blockquote>
<p><br>
</p>
<pre class="moz-signature" cols="72">--
Koen Hillewaert
Fluid Dynamics Technology Leader
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