dolfin team mailing list archive

[Garth Wells <681415@xxxxxxxxxxxxxxxxxx>]

On 22/03/11 05:52, Johan Hake wrote:
> On Monday March 21 2011 13:50:54 Anders Logg wrote:
>> On Mon, Mar 21, 2011 at 07:42:21PM -0000, Garth Wells wrote:
>>> This is also a C++ issue, so should be addressed from that side. A
>>> solution that I thought of a while a ago is to introduce an abstract
>>> base class
>>>
>>>   GenericFunctionSpace
>>>
>>> and make FunctionSpace and SubSpace sub-classes of GenericFunctionSpace.
>>> We would the require a FunctionSpace when creating a Function. For
>>> boundary conditions, we can use a GenericFunctionSpace. At the moment,
>>> SubSpace is a sub-class of FunctionSpace, and this is a cause of
>>> difficulty. We can make it possible to create a FunctionSpace from a
>>> SubSpace, which would basically collapse the dofmap.
>>
>> I think that sounds very good. Similar issues as we had before when
>> the Function class tried to be many things at once (like we can't get
>> the vector of a subspace but we can for a function space).
> 
> Sure, but couldn't this be handled without creating a GenericFunctionSpace. 
> Just feels a bit overkill, when it might be handled with the present interface 
> with some added suger.
> 

sugar -> 'hack' ;)

I think that a GenericFunctionSpace would ultimately be the simplest and
most robust solution. As Anders wrote, we've gotten into trouble in the
past by having the function classes be 'more than one thing'.

Garth

> Johan
>

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https://bugs.launchpad.net/bugs/681415

Title:
  Problem using sub-spaces

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.
  --------------------------------------------------------------------------