ceph/src/boost/libs/mpi/example/in_place_global_min.cpp

   1 // Copyright (C) 2013 Alain Miniussi <alain.miniussi@oca.eu>
   2
   3 // Use, modification and distribution is subject to the Boost Software
   4 // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   5 // http://www.boost.org/LICENSE_1_0.txt)
   6
   7 // An example using Boost.MPI's all_reduce() that compute the minimum
   8 // of each process's value and broadcast the result to all the processes.
   9 #include <boost/mpi.hpp>
  10 #include <iostream>
  11 #include <cstdlib>
  12 namespace mpi = boost::mpi;
  13
  14 int main(int argc, char* argv[])
  15 {
  16   mpi::environment env(argc, argv);
  17   mpi::communicator world;
  18
  19   std::srand(world.rank());
  20   int my_number = std::rand();
  21
  22   all_reduce(world, my_number, mpi::minimum<int>());
  23
  24   if (world.rank() == 0) {
  25       std::cout << "The minimum value is " << my_number << std::endl;
  26   }
  27
  28   return 0;
  29 }