dolfin team mailing list archive

[Mikael Mortensen <681415@xxxxxxxxxxxxxxxxxx>]

On 29 November 2010 17:06, Johan Hake <681415@xxxxxxxxxxxxxxxxxx> wrote:

> On Monday November 29 2010 00:35:27 Mikael Mortensen wrote:
> > Please don't.
> >
> > The subspace functionality is used for example to compute the
> > streamfunction, where the subspace of the velocity VectorFunctionSpace
> > is used. I also use the subspace functionality to assemble into parts of
> > the Navier-Stokes coefficient matrix componentwise. For example
> >
> > uc = TrialFunction(V.sub(0))
> > vc = TestFunction(V.sub(0))
> > a = assemble(inner(grad(uc), grad(vc))*dx)
> >
> > and then I can copy this 'small' matrix to the three diagonal slots of
> > the 3*3 Laplacian matrix that makes up for the whole velocity
> > vectorfield. I understand this is not the regular way of assembling, but
> > it is much faster than switching V.sub(0) above to V and assembling the
> > whole thing by itself.
>
> What hinders you to do:
>
>  Vs = FunctionSpace(mesh, "CG", 1)
>  V  = MixedFunctionSpace([Vs]*3)
>  ...
>  uc = TrialFunction(Vs)
>  vc = TestFunction(Vs)
>   a = assemble(inner(grad(uc), grad(vc))*dx)
>

Nothing really. I used to do that. However, I want to be able to grab the
velocity subpace when I'm computing the streamfunction as I want to use the
same functionspace for the streamfunction as a velocity-component to avoid
any interpolation. I understand that it's not strictly necessary, it's just
a nice functionality the way I see it and I can use the same
streamfunction-code for all velocity-functionspaces.

Mikael


>
> Johan
>
> --
> Problem using sub-spaces
> https://bugs.launchpad.net/bugs/681415
> You received this bug notification because you are a member of DOLFIN
> Team, which is subscribed to DOLFIN.
>
> 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]PETSCERROR: 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.
> --------------------------------------------------------------------------
>
>
>
>
>
>
>
>
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>

-- 
Problem using sub-spaces
https://bugs.launchpad.net/bugs/681415
You received this bug notification because you are a member of DOLFIN
Team, which is subscribed to DOLFIN.

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