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<div class="moz-cite-prefix">Hello,<br>
<br>
I checked out the branch knepley/fix-plex-bc-multiple, but i now
have a strange problem.<br>
I splited my labels as in ex69.c of snes. It may be the right way
to do it.<br>
In petsc 3.8.2, i have the same behavior as before, the element
containing the face is called by PetscDSAddBoundary.<br>
In the git version, PetscDSAddBoundary does not call my boundary
function at all.<br>
The call :<br>
ierr = PetscDSAddBoundary(prob, DM_BC_ESSENTIAL, "wallL",
"markerLeft", 0, Ncomp, components, (void (*)(void)) uIn, 1,
&id, ctx);CHKERRQ(ierr);<br>
<br>
I checked that my labels are correct :<br>
markerLeft: 1 strata with value/size (1 (11))<br>
markerTop: 1 strata with value/size (1 (11))<br>
markerRight: 1 strata with value/size (1 (11))<br>
markerBottom: 1 strata with value/size (1 (11))<br>
<br>
What am i doing wrong ?<br>
<br>
Thanks,<br>
<br>
Regards,<br>
<br>
Yann<br>
<br>
Le 22/11/2017 à 18:51, Matthew Knepley a écrit :<br>
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<blockquote type="cite"
cite="mid:CAMYG4GnHrVg9FVEmM5qny4bRms8w97+fLcpmCBRGMk=jcKvL9A@mail.gmail.com">
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<div class="gmail_quote">On Wed, Nov 22, 2017 at 12:39 PM,
Yann Jobic <span dir="ltr"><<a
href="mailto:yann.jobic@univ-amu.fr" target="_blank"
moz-do-not-send="true">yann.jobic@univ-amu.fr</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">Hello,<br>
<br>
I've found a strange behavior when looking into a bug for
the pressure convergence of a simple Navier-Stokes problem
using PetscFE.<br>
<br>
I followed many examples for labeling boundary faces. I
first use DMPlexMarkBoundaryFaces, (label=1 to the faces).<br>
I find those faces using DMGetStratumIS and searching 1 as
it is the value of the marked boundary faces.<br>
Finally i use DMPlexLabelComplete over the new label.<br>
I then use :<br>
ierr = PetscDSAddBoundary(prob, DM_BC_ESSENTIAL, "in",
"Faces", 0, Ncomp, components, (void (*)(void)) uIn,
NWest, west, NULL);CHKERRQ(ierr);<br>
in order to impose a dirichlet condition for the faces
labeled by the correct value (west=1, south=3,...).<br>
<br>
However, the function "uIn()" is called in all the
Elements containing the boundary faces, and thus impose
the values at nodes that are not in the labeled faces.<br>
Is it a normal behavior ? I then have to test the position
of the node calling uIn, in order to impose the good
value.<br>
I have this problem for a Poiseuille flow, where at 2
corner Elements i have a zero velocity dirichlet condition
(wall) and a In flow velocity one.<br>
</blockquote>
<div><br>
</div>
<div>I believe I have fixed this in
knepley/fix-plex-bc-multiple which should be merged soon.
Do you know how to merge that branch and try?</div>
<div><br>
</div>
<div> Thanks,</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">
The pressure is then very high at the corner nodes of
those 2 Elements.<br>
Do you think my pressure problem comes from there ? (The
velocity field is correct)<br>
<br>
Many thanks,<br>
<br>
Regards,<br>
<br>
Yann<br>
<br>
PS : i'm using those runtime options :<br>
-vel_petscspace_order 2 -pres_petscspace_order 1 \<br>
-ksp_type fgmres -pc_type fieldsplit -pc_fieldsplit_type
schur -pc_fieldsplit_schur_fact_type full \<br>
-fieldsplit_velocity_pc_type lu
-fieldsplit_pressure_ksp_rtol 1.0e-10
-fieldsplit_pressure_pc_type jacobi<br>
<br>
<br>
---<br>
L'absence de virus dans ce courrier électronique a été
vérifiée par le logiciel antivirus Avast.<br>
<a href="https://www.avast.com/antivirus" rel="noreferrer"
target="_blank" moz-do-not-send="true">https://www.avast.com/antiviru<wbr>s</a><br>
<br>
</blockquote>
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-- <br>
<div class="gmail_signature" data-smartmail="gmail_signature">
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<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.caam.rice.edu/%7Emk51/"
target="_blank" moz-do-not-send="true">https://www.cse.buffalo.edu/~knepley/</a><br>
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