[petsc-dev] integer divide by zero when using a two triangle DMPlex

Thu Nov 21 13:48:01 CST 2013

I'm getting the following crash trying to use a two triangle mesh with
DMPlex FEM.  The problem is that the PetscFEGetQuadrature call on line
546 of DMPlexComputeResidualFEM produces a quadrature object with
q.numPoints = 0, which we then use for division.

I'm using the default elements, which based on the "fe dofs" printout
are piecewise constant.

I imagine this is user error, but in addition to fixing it I'd like to
insert another error check into the petsc code so that similar errors
look nicer in future.

Extra data: if I use a slightly larger mesh, it bails with a negative
determinant error.  I don't quite understand how DMPlex determines
orientations, so that may or may be related to this crash.  I'm
building my own DMPlex rather than using one of the existing creation
routines, so it's quite possible my DMPlex is invalid.  An example
determinant error is reproduced below.  For completeness, the DMPlex
creation code is here:

    https://github.com/otherlab/hollow/blob/6fa039bcc2a3308532db45ccd350e201900bcf08/hollow/dm.cpp#L213

Thanks,
Geoffrey

---------------------------------------

(master) cayley:example% ./laplace --resolution 1
mesh counts = [4 5 2]
dm counts   = [4 5 2]
fe dofs = [0 0 1]
fe bd dofs = [0 0 1]
[0]PETSC ERROR:
------------------------------------------------------------------------
[0]PETSC ERROR: Caught signal number 8 FPE: Floating Point
Exception,probably divide by zero
[0]PETSC ERROR: Try option -start_in_debugger or -on_error_attach_debugger
[0]PETSC ERROR: or see
http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind[0]PETSC
ERROR: or try http://valgrind.org on GNU/linux and Apple Mac OS X to
find memory corruption errors
[0]PETSC ERROR: likely location of problem given in stack below
[0]PETSC ERROR: ---------------------  Stack Frames
------------------------------------
[0]PETSC ERROR: Note: The EXACT line numbers in the stack are not available,
[0]PETSC ERROR:       INSTEAD the line number of the start of the function
[0]PETSC ERROR:       is given.
[0]PETSC ERROR: [0] DMPlexComputeResidualFEM line 492
src/dm/impls/plex/plexfem.c
[0]PETSC ERROR: [0] SNESComputeFunction_DMLocal line 63
src/snes/utils/dmlocalsnes.c
[0]PETSC ERROR: [0] SNES user function line 2076 src/snes/interface/snes.c
[0]PETSC ERROR: [0] SNESComputeFunction line 2064 src/snes/interface/snes.c
[0]PETSC ERROR: [0] SNESSolve_NEWTONLS line 144 src/snes/impls/ls/ls.c
[0]PETSC ERROR: [0] SNESSolve line 3755 src/snes/interface/snes.c
[0]PETSC ERROR: --------------------- Error Message
------------------------------------
[0]PETSC ERROR: Signal received!
[0]PETSC ERROR:
------------------------------------------------------------------------
[0]PETSC ERROR: Petsc Development GIT revision:
352a19e720c6e388b1693cf6502c5f90a094459e  GIT Date: 2013-11-20
19:18:56 -0800
[0]PETSC ERROR: See docs/changes/index.html for recent updates.
[0]PETSC ERROR: See docs/faq.html for hints about trouble shooting.
[0]PETSC ERROR: See docs/index.html for manual pages.
[0]PETSC ERROR:
------------------------------------------------------------------------
[0]PETSC ERROR: Unknown Name on a debug named cayley by irving Thu Nov
21 11:34:18 2013
[0]PETSC ERROR: Libraries linked from /home/irving/petsc/debug/lib
[0]PETSC ERROR: Configure run at Wed Nov 20 19:39:25 2013
[0]PETSC ERROR: Configure options --download-ctetgen
--download-exodusii --download-generator --with-debugging=1
--with-fortran=1 --with-hdf5-dir=/usr --with-netcdf-dir=/usr
--with-triangle-dir=/usr PETSC_ARCH=debug
[0]PETSC ERROR:
------------------------------------------------------------------------
[0]PETSC ERROR: User provided function() line 0 in  unknown file
--------------------------------------------------------------------------
MPI_ABORT was invoked on rank 0 in communicator MPI_COMM_WORLD
with errorcode 59.

NOTE: invoking MPI_ABORT causes Open MPI to kill all MPI processes.
You may or may not see output from other processes, depending on
exactly when Open MPI kills them.
--------------------------------------------------------------------------

------------------------------------------------------------------------------

(master) cayley:example% ./laplace --resolution 2
mesh counts = [12 23 12]
dm counts   = [12 23 12]
fe dofs = [0 0 1]
fe bd dofs = [0 0 1]
[0]PETSC ERROR: --------------------- Error Message
------------------------------------
[0]PETSC ERROR: Argument out of range!
[0]PETSC ERROR: Invalid determinant -0.0416667 for element 4!
[0]PETSC ERROR:
------------------------------------------------------------------------
[0]PETSC ERROR: Petsc Development GIT revision:
352a19e720c6e388b1693cf6502c5f90a094459e  GIT Date: 2013-11-20
19:18:56 -0800
[0]PETSC ERROR: See docs/changes/index.html for recent updates.
[0]PETSC ERROR: See docs/faq.html for hints about trouble shooting.
[0]PETSC ERROR: See docs/index.html for manual pages.
[0]PETSC ERROR:
------------------------------------------------------------------------
[0]PETSC ERROR: Unknown Name on a debug named cayley by irving Thu Nov
21 11:42:24 2013
[0]PETSC ERROR: Libraries linked from /home/irving/petsc/debug/lib
[0]PETSC ERROR: Configure run at Wed Nov 20 19:39:25 2013
[0]PETSC ERROR: Configure options --download-ctetgen
--download-exodusii --download-generator --with-debugging=1
--with-fortran=1 --with-hdf5-dir=/usr --with-netcdf-dir=/usr
--with-triangle-dir=/usr PETSC_ARCH=debug
[0]PETSC ERROR:
------------------------------------------------------------------------
[0]PETSC ERROR: DMPlexComputeResidualFEM() line 530 in
src/dm/impls/plex/plexfem.c
[0]PETSC ERROR: SNESComputeFunction_DMLocal() line 75 in
src/snes/utils/dmlocalsnes.c
[0]PETSC ERROR: SNESComputeFunction() line 2077 in src/snes/interface/snes.c
[0]PETSC ERROR: SNESSolve_NEWTONLS() line 175 in src/snes/impls/ls/ls.c
[0]PETSC ERROR: SNESSolve() line 3809 in src/snes/interface/snes.c
[0]PETSC ERROR: --------------------- Error Message
------------------------------------
[0]PETSC ERROR: Argument out of range!
[0]PETSC ERROR:  !
[0]PETSC ERROR:
------------------------------------------------------------------------
[0]PETSC ERROR: Petsc Development GIT revision:
352a19e720c6e388b1693cf6502c5f90a094459e  GIT Date: 2013-11-20
19:18:56 -0800
[0]PETSC ERROR: See docs/changes/index.html for recent updates.
[0]PETSC ERROR: See docs/faq.html for hints about trouble shooting.
[0]PETSC ERROR: See docs/index.html for manual pages.
[0]PETSC ERROR:
------------------------------------------------------------------------
[0]PETSC ERROR: Unknown Name on a debug named cayley by irving Thu Nov
21 11:42:24 2013
[0]PETSC ERROR: Libraries linked from /home/irving/petsc/debug/lib
[0]PETSC ERROR: Configure run at Wed Nov 20 19:39:25 2013
[0]PETSC ERROR: Configure options --download-ctetgen
--download-exodusii --download-generator --with-debugging=1
--with-fortran=1 --with-hdf5-dir=/usr --with-netcdf-dir=/usr
--with-triangle-dir=/usr PETSC_ARCH=debug
[0]PETSC ERROR:
------------------------------------------------------------------------
[0]PETSC ERROR: solve() line 33 in hollow/snes.cpp
Traceback (most recent call last):
  File "./laplace", line 94, in <module>
    main()
  File "./laplace", line 89, in main
    snes.solve(None,u)
RuntimeError: hollow/config.cpp:void hollow::check_failed(const int,
const char *, const char *, const char *, const int):33: Fatal error