Re: Patching Octave-MPI

[JD Cole]

Andy Jacobson wrote:

> > > > > > "Paul" == Paul Kienzle <address@hidden> writes:
> > > > > >            
>
>    Paul> There are a variety of approaches to parallelism which have
>    Paul> been done in matlab m-files and mex-files.  E.g.,
>
> Alex Verstak raised an interesting point last year: he said that the
> MPI standard requires that MPI_Init() be fed the *original* argv and
> argc.  (Yes, it is arguably a silly requirement.)  With at least MPICH
> apparently, MPI_Init() would not work from a .oct file.  See:
>
> http://www.octave.org/mailing-lists/help-octave/2001/141
>
> Later however, Alex apparently did get it running:
>
> http://www.octave.org/mailing-lists/help-octave/2001/218
>
> So perhaps a .oct solution will work.
>
> Note however that the parallelized Matlab solutions all are guided by
> two facts: (1) they cannot modify the source code so the
> parallelization has to work via .mex/.m files, and (2) due to the cost
> of multiple Matlab licenses, there may be implicit assumptions about
> how many instances are running in a given MPI application.  There may
> be hidden performance issues.
>
> It should a pretty trivial matter to determine whether or not the user
> wants a parallel or traditional application when she starts octave.
> Perhaps something as simple as "octave --mpi-server" or "octave
> --mpi-client".  Then we call MPI_Init() (and later MPI_Finalize()) as
> appropriate.  That is just about all that is required from the main
> code; the rest could naturally be moved to .oct.
>
>        Regards,
>
>               Andy
>
>  
I just created mpi_init.oct and mpi_finalize.oct, under LAM, mpi_init 
seems to initialize fine, however when I call the second function, 
mpi_finalize, I get a failure message telling me that a function has 
been called without a call to MPI_Init. This result is consistent with 
what Andy described above, however, in the LAM man page for MPI_Init it 
reads:

MPI mandates that the same thread must call MPI_Init or MPI_Init_thread 
and MPI_Finalize

This leads me to the question: Do all octave DLD functions execute in 
the same thread?

JD