dolfin team mailing list archive

["Garth N. Wells" <gnw20@xxxxxxxxx>]

Anders Logg wrote:
> On Wed, Aug 13, 2008 at 08:03:39PM +0100, Garth N. Wells wrote:
> > I'm experiencing a puzzling problem wth pyDOLFIN and MPI again.
> >
> > When I do
> >
> >      python file.py
> >
> > where file.py is just
> >
> >      from dolfin import *
> >
> >      object = Function("/tmp/fileKFnQpl.xml")
> >      plot(object)
> >      interactive()
> >
> > I see a plot as expected, and get
> >
> >      Plot active, press 'q' to continue.
> >
> > After pressing 'q', I get
> >
> >      *** An error occurred in MPI_Attr_get
> >      *** after MPI was finalized
> >      *** MPI_ERRORS_ARE_FATAL (goodbye)
> >      [gnw20pc:2277] Abort before MPI_INIT completed successfully; not 
> > able to guarantee that all other processes were killed!
> >      *** An error occurred in MPI_Comm_rank
> >      *** after MPI was finalized
> >      *** MPI_ERRORS_ARE_FATAL (goodbye)
> >      *** An error occurred in MPI_Type_free
> >      *** after MPI was finalized
> >      *** MPI_ERRORS_ARE_FATAL (goodbye)
> >      Segmentation fault
> >
> > Somehow, Python appears to be calling MPI_Finalize before DOLFIN gets a 
> > chance to finalise things correctly. Any ideas/experience on how Python 
> > interacts with MPI? I've commented out MPI_Finalize() in DOLFIN to be 
> > sure that DOLFIN is not calling it.
> >
> > Garth
>
> Would it help if we just call MPI_Finalized to check before
> finalizing? We can add a wrapper for it just like for MPI_Initialized.

I've added some annoying debug output to SubSystemsManager. Can you tell 
me what you see when running

    from dolfin import *
    x = PETScVector(10)

When I run it, the first line of output is

    MPI status in initPETSc() 1

which indicates that MPI_Initialize is saying that MPI has been 
initialised before PETSc is initialised, but we haven't initialise it. 
The same code in C++ gives

    MPI status in initPETSc() 0

which is the expected result.

Garth

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