// ==================================================================
// Author: Jean-Michel Richer
// Date: 20 Aug 2016
// Purpose: Use of MPI::Scatter
// The master process creates its own local data and they are send
// to other process (of rank not equal to 0)
// ==================================================================
#include <unistd.h>
#include <unistd.h>  // for sleep

#include <cstdlib>
#include <iostream>
#include <numeric>
using namespace std;
#include "ezmpi.hpp"
using namespace ez::mpi;

/**
 * run master and slaves
 */
void run(int argc, char* argv[]) {
    Process process(argc, argv);

    // local vector
    int local_vec_size = 10;
    vector<int> local_vec(local_vec_size, 0);

    // big vector
    int big_vec_size = process.nbr_processes() * local_vec_size;
    vector<int> big_vec(big_vec_size);

    if (process.is_master()) {
        // master process will send data to others

        iota(big_vec.begin(), big_vec.end(), 1);

        process << "- big vector = " << big_vec << endl;
    }

    // Master sends data to all others
    process.scatter(big_vec, big_vec_size, local_vec);

    // Each process reports the data it has received
    process << "- local vector = " << local_vec << endl;

    process.logs(cout);
}

// ==================================================================
// C++ version
// ==================================================================
int main(int argc, char** argv) {
    // call a function that contains the code for the master and
    // the slaves in order to avoid problems of initialization and
    // finalization of processes
    run(argc, argv);

    exit(EXIT_SUCCESS);
}