[petsc-users] Error in DMFieldComputeFaceData_DS with hex elements

[Matthew Knepley]

On Fri, Jan 18, 2019 at 7:54 AM rickcha--- via petsc-users <
petsc-users at mcs.anl.gov> wrote:

> Dear petsc-team,
>
> I ran into an error when using petscFE in combination with a hex mesh
> constructed with gmsh. The error message reads:
>

Yes, I am guessing that GMsh put some crazy crap in the mesh file. Can you
test it out on a hex mesh from DMPlexCreateBoxMesh()
just ot make sure your physics works? Then we can look at the GMsh file (I
hate that program).


> [0]PETSC ERROR: --------------------- Error Message
> --------------------------------------------------------------
> [0]PETSC ERROR: Petsc has generated inconsistent data
> [0]PETSC ERROR: Not implemented yet
>
> [0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for
> trouble shooting.
> [0]PETSC ERROR: Petsc Development GIT revision: v3.10.3-1227-gcd612eedf5
>  GIT Date: 2019-01-17 05:31:34 +0100
> [0]PETSC ERROR: ./standaloneFEM on a arch-linux2-intel-debug named
> iket127138 by hartig Fri Jan 18 10:49:52 2019
> [0]PETSC ERROR: Configure options PETSC_ARCH=arch-linux2-intel-debug
> --with-debugging=true --with-cc=/home/hartig/intel/bin/icc
> --with-cxx=/home/hartig/intel/bin/icpc
> --with-fc=/home/hartig/intel/bin/ifort --download-mpich --download-ml
> --download-parmetis --download-metis --download-hypre --download-mumps
> --download-scalapack --download-triangle --download-hdf5
> --download-ptscotch --download-chaco
> [0]PETSC ERROR: #1 DMFieldComputeFaceData_DS() line 943 in
> /home/hartig/petsc/src/dm/field/impls/ds/dmfieldds.c
> [0]PETSC ERROR: #2 DMFieldCreateFEGeom() line 537 in
> /home/hartig/petsc/src/dm/field/interface/dmfield.c
> [0]PETSC ERROR: #3 DMSNESGetFEGeom() line 2598 in
> /home/hartig/petsc/src/dm/impls/plex/plexfem.c
> [0]PETSC ERROR: #4 DMPlexComputeBdResidual_Single_Internal() line 1520 in
> /home/hartig/petsc/src/snes/utils/dmplexsnes.c
> [0]PETSC ERROR: #5 DMPlexComputeBdResidual_Internal() line 1649 in
> /home/hartig/petsc/src/snes/utils/dmplexsnes.c
> [0]PETSC ERROR: #6 DMPlexComputeResidual_Internal() line 1946 in
> /home/hartig/petsc/src/snes/utils/dmplexsnes.c
> [0]PETSC ERROR: #7 DMPlexTSComputeIFunctionFEM() line 206 in
> /home/hartig/petsc/src/ts/utils/dmplexts.c
> [0]PETSC ERROR: #8 ComputeI2FunctionWithInertia() line 1284 in
> /home/hartig/cimply/femanalysis.c
> [0]PETSC ERROR: #9 TSComputeI2Function() line 1707 in
> /home/hartig/petsc/src/ts/interface/ts.c
> [0]PETSC ERROR: #10 SNESTSFormFunction_Alpha() line 339 in
> /home/hartig/petsc/src/ts/impls/implicit/alpha/alpha2.c
> [0]PETSC ERROR: #11 SNESTSFormFunction() line 4694 in
> /home/hartig/petsc/src/ts/interface/ts.c
> [0]PETSC ERROR: #12 SNESComputeFunction() line 2301 in
> /home/hartig/petsc/src/snes/interface/snes.c
> [0]PETSC ERROR: #13 SNESSolve_NEWTONLS() line 175 in
> /home/hartig/petsc/src/snes/impls/ls/ls.c
> [0]PETSC ERROR: #14 SNESSolve() line 4454 in
> /home/hartig/petsc/src/snes/interface/snes.c
> [0]PETSC ERROR: #15 TSAlpha_SNESSolve() line 101 in
> /home/hartig/petsc/src/ts/impls/implicit/alpha/alpha2.c
> [0]PETSC ERROR: #16 TSAlpha_Restart() line 143 in
> /home/hartig/petsc/src/ts/impls/implicit/alpha/alpha2.c
> [0]PETSC ERROR: #17 TSStep_Alpha() line 217 in
> /home/hartig/petsc/src/ts/impls/implicit/alpha/alpha2.c
> [0]PETSC ERROR: #18 TSStep() line 3664 in
> /home/hartig/petsc/src/ts/interface/ts.c
> [0]PETSC ERROR: #19 TSSolve() line 3847 in
> /home/hartig/petsc/src/ts/interface/ts.c
>
> Upon investigation, I found that petsc throws the error message because
> coneSize has a value of six. This is the first thing that puzzles me. I
> would have expected a cone size of 4 since we are dealing with faces of hex
> elements. Is it possible that we are on the wrong “level” of the mesh graph
> somehow? Printing "numFaces“ in the debugger, I get the total number of
> elements (not 2D faces) I have in my mesh for the hex-case.
>
> I ran the same case with a simplex mesh and found another thing I don’t
> quite understand: Both times I ran with -petscspace-degree 2. Yet in case
> of the simplex mesh, I get a polynomial degree of 1 in
> DMFieldComputeFaceData_DS (“maxDegree”)
>

I think you are looking at the coordinate space. By default, simplex mesh
use affine coordinate spaces.


> and in case of the hex-mesh, I get a polynomial degree of 3.
>

That is strange. It should be 2.

  Thanks,

    Matt


> In both cases I would have expected the degree to be 2, corresponding to
> Tet10 and Hex20 elements. I might be confusing two different concepts here.
> But this was how I understood the documentation until now.
>
> Thanks,
> Max
>


-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener

https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>
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