Re: [boost] [Boost.MPI] How to use with processes on different machines?

From: Doug Gregor (dgregor_at_[hidden])
Date: 2007-08-31 12:07:22

Hi Manuel,

On Aug 31, 2007, at 9:34 AM, Manuel Jung wrote:
> I would like to know, how i can use Boost.MPI for IPC between  
> different PCs.
> It is described in the introduction:
> "Unlike communication in threaded environments or using a shared- 
> memory
> library, Boost.MPI processes can be spread across many different  
> machines,
> possibly with different operating systems and underlying  
> architectures."
>
> Is there an example, how its done? I cant find one. Or isn't  
> implemented
> yet?

It's implemented, but how it's done depends on the underlying MPI  
implementation and your specific configuration. Boost.MPI builds on  
top of the C MPI interface, for which there are many different  
implementations. Here are some open-source possibilities:

        - Open MPI: http://www.open-mpi.org/
        - MPICH2: http://www-unix.mcs.anl.gov/mpi/mpich2/

If you already have a cluster that you plan to use, there is probably  
an MPI available on that cluster. You would have to consult the  
documentation for that cluster or ask a system administrator how

The simplest way to launch MPI jobs on multiple computers is to  
create a machine file containing the names of all of the computers,  
one per line. You can then provide that machine file to either  
"mpiexec" or "mpirun" (again, depending on the MPI implementation you  
use!) to launch your program, e.g.,

        mpiexec -machinefile myhosts -n 4 ./hello_world

The "mpiexec" program launches jobs on multiple machines, the "- 
machinefile myhosts" tells mpiexec to retrieve the list of machines  
from the file "myhosts", the "-n 4" tells mpiexec to start 4  
different processes, and "./hello_world" is the program to execute on  
all of those processes.

        - Doug