ffc team mailing list archive

["Johannes Ring" <johannr@xxxxxxxxx>]

On Mon, March 30, 2009 20:19, Johan Hake wrote:
> On Monday 30 March 2009 20:06:04 Anders Logg wrote:
>> The buildbot is not responding at the moment so I can't check the
>> status.
>
> All is green except:
>
> The DOLFIN macbot how is complaining about the trilinos demo and the
> DOLFIN
> linux64-exp which complains about:
>
> Traceback (most recent call last):
>   File "./demo.py", line 8, in <module>
>     from dolfin import *
>
> File
> "/work/jhbuildbot/fenics/lib/python2.5/site-packages/dolfin/__init__.py",
> line 16, in <module>
>     from assemble import *
>
> File
> "/work/jhbuildbot/fenics/lib/python2.5/site-packages/dolfin/assemble.py",
> line 25, in <module>
>     import cpp
>   File
> "/work/jhbuildbot/fenics/lib/python2.5/site-packages/dolfin/cpp.py",
> line 25, in <module>
>     import _cpp
> ImportError: /work/jhbuildbot/local/lib/openmpi/mca_paffinity_linux.so:
> undefined symbol: mca_base_param_reg_int
>
> I know Johannes has tried to get into this but as far as I know with no
> success.

This is a problem with PyDOLFIN and Open MPI 1.3. We (me and Johan) had
success with a small hack this morning. By adding

  import ctypes
  ctypes.CDLL('libmpi.so', ctypes.RTLD_GLOBAL)

before loading the cpp module in site-packages/dolfin/__init__.py the
Python poisson demo ran just fine. Alternatively one should be able to use
this instead:

  import dl
  import sys
  flags = sys.getdlopenflags()
  sys.setdlopenflags(flags | dl.RTLD_GLOBAL)

but because of a bug in the python2.5 package in Hardy (missing dl module)
we couldn't test this.

It might also be possible to do this in C++ directly. Any suggestion on
the best way to fix this issue? See also:

http://fenics.org/pipermail/deb-dev/2009-March/000210.html
http://www.open-mpi.org/faq/?category=running#loading-libmpi-dynamically

Open MPI 1.3 is in Debian unstable so it would be great if we could fix
this before the release.

Johannes