<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><br><div><br><blockquote type="cite"><div>On 27 Feb 2023, at 3:59 PM, Matthew Knepley <knepley@gmail.com> wrote:</div><br class="Apple-interchange-newline"><div><meta charset="UTF-8"><div dir="ltr" style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;"><div dir="ltr">On Mon, Feb 27, 2023 at 9:53 AM Zongze Yang <<a href="mailto:yangzongze@gmail.com">yangzongze@gmail.com</a>> wrote:<br></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-style: solid; border-left-color: rgb(204, 204, 204); padding-left: 1ex;"><div dir="ltr"><div>Hi, Matt,</div><div><br></div>I tested coarsening a mesh by using ParMMg without firedrake, and found some issues:<div> see the code and results here: <a href="https://gitlab.com/petsc/petsc/-/issues/1331" target="_blank">https://gitlab.com/petsc/petsc/-/issues/1331</a></div><div><br></div><div>Could you have a look and give some comments or suggestions?</div></div></blockquote><div><br></div><div>I replied on the issue. More generally, the adaptive refinement software has not seen wide use</div></div></div></div></blockquote><div><br></div><div>:)</div><div>Matt probably meant “the _DMPlex interface_ to adaptive refinement software has not seen wide use”, Mmg has been rather widely used for 10+ years (here is a 13-year old presentation <a href="https://www.ljll.math.upmc.fr/hecht/ftp/ff++days/2010/exposes/Morice-MeshMetric.pdf">https://www.ljll.math.upmc.fr/hecht/ftp/ff++days/2010/exposes/Morice-MeshMetric.pdf</a>).</div><div><br></div><div>Thanks,</div><div>Pierre</div><br><blockquote type="cite"><div><div dir="ltr" style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;"><div class="gmail_quote"><div>, and I expect</div><div>more of these kinds of bugs until more people use it.</div><div><br></div><div> Thanks,</div><div><br></div><div> Matt</div><div> </div><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-style: solid; border-left-color: rgb(204, 204, 204); padding-left: 1ex;"><div dir="ltr"><div><div><div><div dir="ltr"><div dir="ltr">Best wishes,<div>Zongze</div></div></div></div><br></div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, 27 Feb 2023 at 20:19, Matthew Knepley <<a href="mailto:knepley@gmail.com" target="_blank">knepley@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-style: solid; border-left-color: rgb(204, 204, 204); padding-left: 1ex;"><div dir="ltr"><div dir="ltr">On Sat, Feb 18, 2023 at 6:41 AM Zongze Yang <<a href="mailto:yangzongze@gmail.com" target="_blank">yangzongze@gmail.com</a>> wrote:<br></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-style: solid; border-left-color: rgb(204, 204, 204); padding-left: 1ex;"><div dir="ltr">Another question on mesh coarsening is about `DMCoarsen` which will fail when running in parallel.<div><br></div><div>I generate a mesh in Firedrake, and then create function space and functions, after that, I get the dmplex and coarsen it.</div><div>When running in serials, I get the mesh coarsened correctly. But it failed with errors in ParMMG when running parallel.</div><div><br></div><div>However, If I did not create function space and functions on the original mesh, everything works fine too.</div><div><br></div><div>The code and the error logs are attached.</div></div></blockquote><div><br></div><div>I believe the problem is that Firedrake and PETSc currently have incompatible coordinate spaces. We are working</div><div>to fix this, and I expect it to work by this summer.</div><div><br></div><div> <span class="Apple-converted-space"> </span>Thanks,</div><div><br></div><div> Matt</div><div> </div><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-style: solid; border-left-color: rgb(204, 204, 204); padding-left: 1ex;"><div dir="ltr"><div>Thank you for your time and attention。<br></div><div><br clear="all"><div><div dir="ltr"><div dir="ltr">Best wishes,<div>Zongze</div></div></div></div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sat, 18 Feb 2023 at 15:24, Zongze Yang <<a href="mailto:yangzongze@gmail.com" target="_blank">yangzongze@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-style: solid; border-left-color: rgb(204, 204, 204); padding-left: 1ex;"><div dir="ltr"><div>Dear PETSc Group,</div><div><br></div><div>I am writing to inquire about the function DMAdaptLabel in PETSc. </div><div>I am trying to use it coarse a mesh, but the resulting mesh is refined.</div><div><br></div><div>In the following code, all of the `adpat` label values were set to 2 (DM_ADAPT_COARSEN).</div><div>There must be something wrong. Could you give some suggestions?</div><div> <br></div><div>```python</div><div>from firedrake import *<br>from firedrake.petsc import PETSc<br><br>def mark_all_cells(mesh):<br> <span class="Apple-converted-space"> </span>plex = mesh.topology_dm<br> <span class="Apple-converted-space"> </span>with PETSc.Log.Event("ADD_ADAPT_LABEL"):<br> <span class="Apple-converted-space"> </span>plex.createLabel('adapt')<br> <span class="Apple-converted-space"> </span>cs, ce = plex.getHeightStratum(0)<br> <span class="Apple-converted-space"> </span>for i in range(cs, ce):<br> <span class="Apple-converted-space"> </span>plex.setLabelValue('adapt', i, 2)<br> <span class="Apple-converted-space"> </span><br> <span class="Apple-converted-space"> </span>return plex<br><br>mesh = RectangleMesh(10, 10, 1, 1)<br><br>x = SpatialCoordinate(mesh)<br>V = FunctionSpace(mesh, 'CG', 1)<br>f = Function(V).interpolate(10 + 10*sin(x[0]))<br>triplot(mesh)<br><br>plex = mark_all_cells(mesh)<br>new_plex = plex.adaptLabel('adapt')<br>mesh = Mesh(new_plex)<br>triplot(mesh)<br></div><div>```</div><div><br>Thank you very much for your time.<br></div><br>Best wishes,<br><div><div dir="ltr"><div dir="ltr"><div>Zongze</div></div></div></div></div></blockquote></div></blockquote></div><br clear="all"><div><br></div>--<span class="Apple-converted-space"> </span><br><div dir="ltr"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div>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><br></div><div><a href="http://www.cse.buffalo.edu/~knepley/" target="_blank">https://www.cse.buffalo.edu/~knepley/</a><br></div></div></div></div></div></div></div></div></blockquote></div></blockquote></div><br clear="all"><div><br></div>--<span class="Apple-converted-space"> </span><br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div>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><br></div><div><a href="http://www.cse.buffalo.edu/~knepley/" target="_blank">https://www.cse.buffalo.edu/~knepley/</a></div></div></div></div></div></div></div></div></div></blockquote></div><br></body></html>