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- // Copyright (C) 2013 Andreas Hehn <hehn@phys.ethz.ch>, ETH Zurich
- // based on
- // hellp-world_broadcast.cpp (C) 2006 Douglas Gregor <doug.gregor@gmail.com>
- // Use, modification and distribution is subject to the Boost Software
- // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
- // http://www.boost.org/LICENSE_1_0.txt)
- // A simple Hello world! example
- // using boost::mpi::group and boost::mpi::broadcast()
- #include <stdexcept>
- #include <boost/mpi/environment.hpp>
- #include <boost/mpi/communicator.hpp>
- #include <boost/mpi/group.hpp>
- #include <boost/mpi/collectives.hpp>
- #include <boost/serialization/string.hpp>
- namespace mpi = boost::mpi;
- int main(int argc, char* argv[])
- {
- mpi::environment env(argc, argv);
- mpi::communicator world;
- if(world.size() < 2)
- throw std::runtime_error("Please run with at least 2 MPI processes!");
- int group_a_ranks[2] = {0,1};
- mpi::group world_group = world.group();
- mpi::group group_a = world_group.include(group_a_ranks,group_a_ranks+2);
- mpi::communicator comm_a(world,group_a);
- std::string value("Hello world!");
- if(comm_a)
- {
- if(comm_a.rank() == 0) {
- value = "Hello group a!";
- }
- mpi::broadcast(comm_a, value, 0);
- }
- std::cout << "Process #" << world.rank() << " says " << value << std::endl;
- return 0;
- }
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