[Boost-users] Boost.MPI --- boost::mpi::group class

Subject: [Boost-users] Boost.MPI --- boost::mpi::group class
From: Júlio Hoffimann (julio.hoffimann_at_[hidden])
Date: 2011-02-07 12:23:48

Hi,

It's my first time using Boost and is amazing. I'm trying to understand why
this simple example bellow don't works as expected:

#include <iostream>
#include <boost/mpi.hpp>

using namespace std;
namespace mpi = boost::mpi;

int main ( int argc, char *argv[] )
{
mpi::environment env( argc, argv );
mpi::communicator world;
mpi::group subgroup( MPI_Group( world.group() ), true );

cout  << "I'm process "                          <<   world.rank()       <<
endl;
cout  << "But in subgroup i'm process "  <<   subgroup.rank()  << endl;
cout  << "And the subgroup size is... "   <<   subgroup.size()   << endl;

return 0;
}  // ----------  end of function main  ----------

*1. Why every process has rank 1 in subgroup? I trying to figure out what
happens, but without success.*

The mpi::boost::group class has no copy constructor explicitly defined. That
is true for many other classes in Boost.MPI...

*2. It's safe to use the copy constructor generated by the compiler as
follows?*
*
*
mpi::group subgroup = world.group().exclude( discardedRanks.begin(),
discardedRanks.end() );

Thanks in advance for any help.

Regards,
Júlio.