The ABINIT Users Mailing List ( CLOSED )

[Marc Torrent <marc.torrent@cea.fr>]

Eric (and Masao Arai),

In fact you were right when you said:
"mpif.h should match whatever the MPI library was compiled with"
And my answer also was right when I said that Abinit assumes that 
MPI_COMM_WORLD is not 91.
After a discussion with Mireille Boulet, we decided to produce a patch 
in order to make Abinit work with all version of mpif.h.
So Mireille has written that patch and it will be soon available in the
- Abinit v4.3.4 release (coming soon)
- Abinit v4.4.3 release
and 4.5.x releases of course.

I hope it will help you,

Best wishes,

Marc


Eric Roman a écrit :
> Marc,
>
> I don't understand this advice.
>
> mpif.h should match whatever the MPI library was compiled with.  Nothing else.
> The MPI library was built expecting MPI_COMM_WORLD to be zero.  That's why
> it's defined to be zero in the header file that ships with the libraries.
>
> If the MPI library is compiled thinking MPI_COMM_WORLD is 0, and it gets
> 91, the MPI library will see an uninitialized communicator, and return
> MPI_ERR_COMM.
>
> Since the MPI library has been compiled already, MPI_COMM_WORLD is just a
> constant in the binary, (0 in his case)!  If the headers don't match the
> MPI libraries, there will be problems.  This is like copying say, math.h or
> unistd.h from a Solaris Sparc system to a Linux x86 ystem, and expecting it
> to work.  It might compile.  Things might even run in some cases.  But only
> by sheer coincidence.
>
> AFAIK, there is no part of the MPI specification that says MPI_COMM_WORLD
> is nonzero.  In fact, MPI_COMM_WORLD is zero in both LAM MPI, IBM's MPI,
> Hitachi's MPI, and perhaps some versions of MPICH.  This assumption breaks
> compatibility with those platforms.  I can't run the newer abinit versions
> in parallel on our local IBM SP because of this assumption.  abinit won't
> run in parallel with LAM MPI because of this assumption.  And now abinit
> won't run in parallel on this Hitachi machine.
>
> The assumption that MPI_COMM_WORLD is non-zero is a mistake.  There's
> nothing definitive about MPICH's version of mpif.h.  (In MPICH 2 they set
> MPI_COMM_WORLD to 114085068).  When compiling, you have to use the headers
> that match your binaries.  And when writing code, the only thing you can
> count on is what's inside the MPI specification.  Nowhere does the MPI spec
> say that MPI_COMM_WORLD is nonzero.
>
> This is a bug, and one that I'd like to fix.  Would you be able to put me in
> touch with Mireille Boulet?
>
> Best Wishes,
> Eric 
>
> On Thu, Oct 07, 2004 at 05:36:14PM +0200, Marc Torrent wrote:
>
> > Dear Arai Masao,
> >
> > I seems that you're using an "old" version of mpif...
> > Abinit's parallelization has been recently revised (by Mireille Boulet, 
> > here at the CEA-Bruyeres-le_Chatel, France) and these modifications are 
> > using the new version of the "mpif.h" where MPI_COMM_WOLRD is 91 and 
> > MPI_COMM_SELF is 92.
> > (In fact, in older version of mpif.h, MPI_COMM_WORLD=0 and MPI_COMM_SELF=1).
> >
> > If you want Abinit v433 to run on your Hitachi, you have to use a newer 
> > version of mpif.h (for ex. v1.2.5.2).
> >
> >
> > Regards,
> >
> > Marc Torrent
> > CEA-Bruyeres-le-Chatel
> > France
> >
> >
> > Arai Masao a écrit :
> >
> > > Dear all,
> > >
> > > I am a collaborator of Wang Yuan Xu who asked some questions
> > > about abinit on Hitachi SR-11000. Thank you for your kind replies.
> > >
> > > I found possible reason why the abinit-4.3.3 does not work on this machine
> > > in parallel mode.
> > >
> > > In SR11000, MPI_COMM_WORLD is defined to 0 in /usr/include/mpif.h.
> > > ---- mpif.h -----
> > >     integer*4 MPI_COMM_WORLD,MPI_COMM_SELF
> > >     parameter (MPI_COMM_WORLD=0,MPI_COMM_SELF=1)
> > > ------------------
> > >
> > > Unfortunately, the zero has special meaning in 
> > > Src_1managempi/xdef_comm.f and
> > > Src_1managempi/xfuncmpi.f.
> > >
> > > --- xdeff_comm.f ----
> > > subroutine xcomm_world(spaceComm)
> > >    [ lines deleted]
> > > integer  :: spaceComm
> > > #          if defined MPI
> > >               spaceComm = MPI_COMM_WORLD
> > > #          else
> > >               spaceComm = 0
> > > #          endif
> > > --------------------------------
> > >
> > > --- xfuncmpi.f  ----
> > > subroutine xsum_mpi_int(xval,spaceComm,ier)
> > >       [lines deleted]
> > > #          if defined MPI || defined MPI_FFT
> > >               integer , allocatable :: xsum(:)
> > >               if (spaceComm /= 0) then                   <<<<<<<<<<<<  #1
> > >         !Accumulate xval on all proc. in spaceComm
> > >       [lines deleted]
> > > end subroutine xsum_mpi_int
> > > -------
> > >
> > > With the  line indicated by "#1", if the spaceComm is set to 
> > > MPI_COMM_WORLD(=0),
> > > the mpi routines does not work properly.
> > > The version 4.2 does not have such checks. So, abinit-4.2 works properly
> > > even on SR11000.
> > >
> > > If we remove the  comparison between spaceComm and 0, the parallel mode
> > > seems to work properly. Is it safe to remove this comparison?
> > >
> > > --
> > > Masao ARAI
> > > National Institute for Materials Science (NIMS)
> > > Computational Materials Science Center
> > > First-Principles Simulation Group (II)
> > > mail: arai.masao@nims.go.jp