<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Wed, Aug 17, 2016 at 2:35 PM, Justin Chang <span dir="ltr"><<a href="mailto:jychang48@gmail.com" target="_blank">jychang48@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">Because the base mesh starts off with 6 elements and 8 vertices. This is enough data for one cell per MPI process. Refinement is done after DMPlexDistribute(...). If I use anymore than 6 cores, some of the MPI ranks will have an empty DM Object. For example:</div></blockquote><div><br></div><div>You could</div><div><br></div><div>1) Just stick an explicit call to uniform refinement in for the serial mesh</div><div><br></div><div>2) Use a cell volume that is 1/N, where N is the number of cells you want</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><p style="margin:0px;font-size:12px;line-height:normal;font-family:Courier;color:rgb(76,47,45);background-color:rgb(223,219,196)"><span>$ mpirun -n 8 --bind-to-core --bysocket ./ex12 -dim 3 -run_type full -interpolate 1 -petscspace_order 1 -bc_type dirichlet -ksp_rtol 1.0e-7 -pc_type ml -refinement_limit 1 -dm_refine 1 -dm_view</span></p>
<p style="margin:0px;font-size:12px;line-height:normal;font-family:Courier;color:rgb(76,47,45);background-color:rgb(223,219,196)"><span>DM Object: Parallel Mesh 8 MPI processes</span></p>
<p style="margin:0px;font-size:12px;line-height:normal;font-family:Courier;color:rgb(76,47,45);background-color:rgb(223,219,196)"><span> type: plex</span></p>
<p style="margin:0px;font-size:12px;line-height:normal;font-family:Courier;color:rgb(76,47,45);background-color:rgb(223,219,196)"><span>Parallel Mesh in 3 dimensions:</span></p>
<p style="margin:0px;font-size:12px;line-height:normal;font-family:Courier;color:rgb(76,47,45);background-color:rgb(223,219,196)"><span> 0-cells: 10 0 10 10 10 0 10 10</span></p>
<p style="margin:0px;font-size:12px;line-height:normal;font-family:Courier;color:rgb(76,47,45);background-color:rgb(223,219,196)"><span> 1-cells: 25 0 25 25 25 0 25 25</span></p>
<p style="margin:0px;font-size:12px;line-height:normal;font-family:Courier;color:rgb(76,47,45);background-color:rgb(223,219,196)"><span> 2-cells: 24 0 24 24 24 0 24 24</span></p>
<p style="margin:0px;font-size:12px;line-height:normal;font-family:Courier;color:rgb(76,47,45);background-color:rgb(223,219,196)"><span> 3-cells: 8 0 8 8 8 0 8 8</span></p>
<p style="margin:0px;font-size:12px;line-height:normal;font-family:Courier;color:rgb(76,47,45);background-color:rgb(223,219,196)"><span>Labels:</span></p>
<p style="margin:0px;font-size:12px;line-height:normal;font-family:Courier;color:rgb(76,47,45);background-color:rgb(223,219,196)"><span> marker: 1 strata of sizes (18)</span></p>
<p style="margin:0px;font-size:12px;line-height:normal;font-family:Courier;color:rgb(76,47,45);background-color:rgb(223,219,196)"><span> depth: 4 strata of sizes (10, 25, 24, 8)</span></p>
<p style="margin:0px;font-size:12px;line-height:normal;font-family:Courier;color:rgb(76,47,45);background-color:rgb(223,219,196)"><span>Number of SNES iterations = 1</span></p>
<p style="margin:0px;font-size:12px;line-height:normal;font-family:Courier;color:rgb(76,47,45);background-color:rgb(223,219,196)"><span>L_2 Error: 0.118178</span></p></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Aug 17, 2016 at 2:28 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"><span>On Wed, Aug 17, 2016 at 2:04 PM, Justin Chang <span dir="ltr"><<a href="mailto:jychang48@gmail.com" target="_blank">jychang48@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">When I enter values like 1/16, 1/12, 1/24, and so on, I was expecting to get roughly the same dm object as if I simply did -dm_refine <0/1/2/3>. Instead it seems I get highly unstructured grids, and the smaller the number gets, the fewer additional cells I get. Is there a way to make the refinement limit uniform?</div></blockquote><div><br></div></span><div>Why not just use -dm_refine ?</div><div><br></div><div> Matt</div><span><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="gmail_extra"><div class="gmail_quote">On Wed, Aug 17, 2016 at 9:38 AM, 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"><span>On Wed, Aug 17, 2016 at 5:23 AM, Justin Chang <span dir="ltr"><<a href="mailto:jychang48@gmail.com" target="_blank">jychang48@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">Hi all,<div><br></div><div>Playing around with SNES ex12.c and I am attempting to tinker around with 3D options. I am trying to understand what kind of values go into -refinement_limit for 3D simplices.</div></div></blockquote><div><br></div></span><div>The cell volume limits for any cells created out of the existing cells. This is how TetGen understands refinement. I think a</div><div>better way is to use a metric tensor field, and we now have an interface to pragmatic for this (I think currently I only hooked it up</div><div>to DMCoarsen() but it does both). Clearly the interface is immature, but this is the way we are headed.</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>Thanks,</div><div>Justin</div></div><span><font color="#888888">
</font></span></blockquote></div><span><font color="#888888"><br><br clear="all"><span class="HOEnZb"><font color="#888888"><span><font color="#888888"><div><br></div>-- <br><div data-smartmail="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>
</font></span></font></span></font></span></div></div><span class="HOEnZb"><font color="#888888">
</font></span></blockquote></div><span class="HOEnZb"><font color="#888888"><br></font></span></div><span class="HOEnZb"><font color="#888888">
</font></span></blockquote></span></div><span class="HOEnZb"><font color="#888888"><span><br><br clear="all"><div><br></div>-- <br><div data-smartmail="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>
</span></font></span></div></div>
</blockquote></div><br></div>
</blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature" data-smartmail="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>
</div></div>