#include <boost/mpi.hpp>
#include <boost/serialization/string.hpp>
#include <iostream>
#include <math.h>
#include <string>
int main(int argc, char * argv[]) {
/*Simple general Boost.MPI example*/

/*!MPI initialization*/
boost::mpi::environment env(argc,argv);
boost::mpi::communicator world;

/*Initialize "global" variables*/
int root=0; /*The process that will do the receiving and output*/

/*Do "the work" (by all processes)*/
/*Waste some time, so that the program takes a noticeable time to finish*/
int length=100000;
double atmp[length],btmp[length];
for (int i=0; i<length; i++) atmp[i]=(i-1)/((length-1)*1e0);
for (int i=0; i<100; i++) btmp[i]=acos(cos(atmp[i]*acos(-1e0)));
/*End of "the work"*/

/*Get the results from everybody*/
std::vector<std::string> proc_names; /*Where the names will go*/
std::vector<int> proc_ranks; /*Where the numbers will go*/
std::string name=boost::mpi::environment::processor_name();
if (world.rank()==root) { /*If root, must provide a place to store the data*/
  gather(world,world.rank(),proc_ranks,root);
  gather(world,name,proc_names,root);
} else { /*If not root, just send the data to the gather*/
  gather(world,world.rank(),root);
  gather(world,name,root);
}

/*Show the results (only the root process does this)*/
if (world.rank()==root) {
  std::cout<<"I am process number "<<world.rank()<<std::endl;
  std::cout<<"Running on processor "<<proc_names[world.rank()]<<std::endl;
  std::cout<<"Number of tasks is "<<world.size()<<std::endl;
  for (int i=0; i<world.size(); i++){
    std::cout<<"Process rank "<<proc_ranks[i]<<" ran on processor ";
    std::cout<<proc_names[i]<<std::endl;
  }
}
}