MPI/Beowulf vs. SM Programming/OpenMP

Craig Tierney ctierney at
Fri Mar 30 12:47:55 PST 2001

I guess I am confused now.  Are you saying you want to be able
to startup a.out on 3 processors and b.out on 2 processors and
have them talk to each other over MPI (mpich)?

Mpich can do this (I think it is with the -p4pg option).  I use
gm over mpich and I do this as well.  I have to modify the mpirun
script (Myricom's verison doesn't support it) but I have users
that do this now on the system.


On Fri, Mar 30, 2001 at 11:44:57AM -0800, Mattson, Timothy G wrote:
> Rusty,
> I guess my post wasn't clear enough.  
> I am working with a software vendor.  They need to launch several different
> programs that interact through MPI.  You can do this in PVM, you can do this
> with LAM/MPI, but you can't do this with MPIch.  Or I should say, I don't
> think it can be done with MPIch.  The folks at this company looked into the
> matter and independently reached the same conclustion.
> As I see it, with MPIch, I must have everything in a single program.  Yes,
> the programs can execite readically different pathways so in most cases,
> this doesn't restrict the algorithms I can work with.  There are other
> engineering issues, however, that sometimes force  me to run completely
> different programs that cooperate through MPI.  This is the situation the
> un-named software vendor is faced with.
> So that is is what I meant by my general Multiple Program Multiple Data (or
> MPMD) comment.
> Does this make sense?  Did I get something wrong and it is indeed the case
> that MPIch can handle this situation?  I'd love to be wrong as it would make
> my life simpler if I could do everything with only one version of MPI.
> --Tim  
> -----Original Message-----
> From: Rusty Lusk [mailto:lusk at]
> Sent: Thursday, March 29, 2001 11:15 AM
> To: Mattson, Timothy G
> Cc: 'Chris Richard Adams'; Beowulf (E-mail)
> Subject: Re: MPI/Beowulf vs. SM Programming/OpenMP 
> | A general MPMD algorithm with lots of assynchronous events would be hard
> to
> | do with OpenMP.  (actually, it can be hard with MPIch as well, but then
> you
> | can go with MPI-LAM or PVM).
> Hi Tim,
> I am curious as to what you are referring to with regard to MPICH.  
> Rusty
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Craig Tierney (ctierney at
phone: 303-497-3112

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