Re: PetSc

[Camm Maguire <camm@enhanced.com>]

Greetings!

Junichi Uekawa <dancer@netfort.gr.jp> writes:

> In Thu, 11 Jan 2001 12:14:02 -0500 Adam C Powell IV <hazelsct@mit.edu> cum veritate scripsit :
> 
> > Right.  The other problem is that mpirun takes different arguments for
> > mpich and lam, and
> > PETSc comes with a compatibility wrapper script "mpirun.lam" which takes
> > arguments in mpich
> > format.  
> 
> Hmmm.. that's very interesting. 
> 

My understanding is that the most recent lam's mpirun can take the
same syntax as mpich's, though it has additional options as well.
Could be mistaken on this, as am not too familiar with mpich.  Here is
the latest synopsis:

       mpirun [-fhvO] [-c <#> | -np <#>] [-D | -wd <dir>] [-ger |
              -nger] [-c2c | -lamd] [-nsigs] [-nw | -w] [-nx]
              [-pty] [-s <node>] [-t | -toff | -ton] [-x
              VAR1[=VALUE1][,VAR2[=VALUE2],...]]  [<nodes>]
              <program> [-- <args>]

       mpirun [-fhvO] [-D | -wd <dir>] [-ger | -nger] [-lamd |
              -c2c] [-nsigs] [-nw | -w] [-nx] [-pty] [-t | -toff
              | -ton] [-x VAR1[=VALUE1][,VAR2[=VALUE2],...]]
              <schema>


> > Oh- and mpich doesn't have shared libs, so when you link -mpi
> > and
> > /etc/alternatives points to mpich, there are dangling symlinks for
> > libmpi.so. :-(
> 
> Actually it is possible to build shared library for mpich, and
> I tried it. It was not very exciting. 
> 

Not too exciting?  Sounds like real progress to me!  Is the latest
mpich package equipped with these shared libs?=

> Hmmm.. I didn't know there was a dangling symlink. 
> Okay... please file a bug.
> 
> 
> 
> Ah, yes. This is a nightmare, trying to compile against mpich AND lam.
> 

Maybe its not so bad.  We have the scalapack package as an example.

Meanwhile, I've been discussing the binary compatibility issue with
the lam authors, and it may not be quite as difficult as we had
thought, (only if both implementations use shared libs, of course).
Even if this were achieved, we'd have a Debian problem:  with the
alternatives scheme, compiling against -lmpi will produce a binary
with ldd reporting linkage against liblam or libmpich -- the compiler
goes straight through the symbolic links.  Maybe this can be handled
with a compiler/linker flag, but otherwise, we'd have to fall back on
diversions (e.g. dpkg-divert) for libmpi.


> 
> regards,
> 	junichi
> 

Take care,

> --
> University: ti0113@mail4.doshisha.ac.jp    Netfort: dancer@netfort.gr.jp
> dancer, a.k.a. Junichi Uekawa   http://www.netfort.gr.jp/~dancer
>  Dept. of Knowledge Engineering and Computer Science, Doshisha University.
> ... Long Live Free Software, LIBERTAS OMNI VINCIT.
> 
> 
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> 

-- 
Camm Maguire			     			camm@enhanced.com
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"The earth is but one country, and mankind its citizens."  --  Baha'u'llah