dolfin team mailing list archive

[Johan Hake <681415@xxxxxxxxxxxxxxxxxx>]

I suggest we make it impossible to create a Function from
dolfin.SubSpace. If a user want a sub function he should use one of:

  u.split(0)
  u.split(0, True)
  u[0]

Is a Subspace used for anything else than in the construction of
DirichletBC? Also is the class FunctionSpaceFromCpp used for anything
else that the construction of a SubSpace in the method
FunctionSpace.sub?

-- 
Problem using sub-spaces
https://bugs.launchpad.net/bugs/681415
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Status in DOLFIN: Confirmed

Bug description:
Hi,

I have trouble using MixedFunctionSpace. Basically I want to project a function to a subspace of a MixedFunctionSpace:

   from dolfin import *
   mesh=UnitInterval(10)
   U = FunctionSpace(mesh, "CG", 1)
   V = FunctionSpace(mesh, "CG", 1)
   W=U*V
   f1=Function(W.sub(0))
   f1.vector()[:]=1.0
   #f2=project(f1, V)   # This works!
   f2=project(f1, W.sub(1))  # This doesn't!


The output of that script is attached to the end of this question. Now, the confusing thing is that the projection works fine if one projects to V instead of W.sub(1), although they are mathematically the same spaces. 

I hope I haven't missed a similar question already reported. 

Best wishes,

Simon


[0]PETSC ERROR: ------------------------------------------------------------------------
[0]PETSC ERROR: Caught signal number 11 SEGV: Segmentation Violation, probably memory access out of range
[0]PETSC ERROR: Try option -start_in_debugger or -on_error_attach_debugger
[0]PETSC ERROR: or see http://www.mcs.anl.gov/petsc/petsc-as/documentation/troubleshooting.html#Signal[0]PETSC ERROR: or try http://valgrind.org on GNU/linux and Apple Mac OS X to find memory corruption errors
[0]PETSC ERROR: configure using --with-debugging=yes, recompile, link, and run 
[0]PETSC ERROR: to get more information on the crash.
[0]PETSC ERROR: --------------------- Error Message ------------------------------------
[0]PETSC ERROR: Signal received!
[0]PETSC ERROR: ------------------------------------------------------------------------
[0]PETSC ERROR: Petsc Release Version 3.1.0, Patch 3, Fri Jun  4 15:34:52 CDT 2010
[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 linux-gnu named doodson by sf1409 Thu Nov 25 13:17:44 2010
[0]PETSC ERROR: Libraries linked from /build/buildd/petsc-3.1.dfsg/linux-gnu-c-opt/lib
[0]PETSC ERROR: Configure run at Fri Sep 10 04:57:14 2010
[0]PETSC ERROR: Configure options --with-shared --with-debugging=0 --useThreads 0 --with-clanguage=C++ --with-c-support --with-fortran-interfaces=1 --with-mpi-dir=/usr/lib/openmpi --with-mpi-shared=1 --with-blas-lib=-lblas --with-lapack-lib=-llapack --with-umfpack=1 --with-umfpack-include=/usr/include/suitesparse --with-umfpack-lib="[/usr/lib/libumfpack.so,/usr/lib/libamd.so]" --with-spooles=1 --with-spooles-include=/usr/include/spooles --with-spooles-lib=/usr/lib/libspooles.so --with-hypre=1 --with-hypre-dir=/usr --with-scotch=1 --with-scotch-include=/usr/include/scotch --with-scotch-lib=/usr/lib/libscotch.so --with-hdf5=1 --with-hdf5-dir=/usr
[0]PETSC ERROR: ------------------------------------------------------------------------
[0]PETSC ERROR: User provided function() line 0 in unknown directory 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.
--------------------------------------------------------------------------