// ==================================================================
// 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 <iostream>
#include <cstdlib>
#include <unistd.h> // for sleep
using namespace std;
#include "ezmpi.h"
using namespace ez::mpi;

/**
 * run master and slaves
 */
void run(int argc, char *argv[]) {
	
	Process p(argc, argv);
	
	const int local_data_size = 10;
	int *local_data;
	int global_data_size = p.max() * local_data_size;
	int *global_data = NULL;
	
	local_data = new int [ local_data_size ];
	for (int i=0; i<local_data_size; ++i) {
		local_data[i] = 0;
	}
		
	
	if (p.is_master()) {
	
		// master process will send data to others
		global_data = new int [ global_data_size ];
		for (int i=0; i<global_data_size; ++i) global_data[i] =  i+1;
		
		p << "global array = [";
		for (int i=0; i<global_data_size; ++i) p << global_data[i] << " ";
		p << "]" << endl;
	}
	
	// Master sends data to all others
	p.scatter(global_data, local_data_size, local_data);
	
	// Each process reports the data it has received			
	p << "local array=[";
	for (int i=0; i<local_data_size; ++i) {
		p << local_data[i] << " ";
	}
	p << "]" << endl;

	sleep(1);
   	
   	p.logs(cout);
}

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