#include <stdio.h>
#include <unistd.h>
#include <mpi.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>



//Example compilation
//mpicc scatter_starter.c -lm -o scatter_starter

//Example execution
//mpirun -np 1 -hostfile myhostfile.txt ./scatter_starter 10000



int main(int argc, char **argv) {

  int my_rank, nprocs;

  MPI_Init(&argc,&argv);
  MPI_Comm_rank(MPI_COMM_WORLD,&my_rank);
  MPI_Comm_size(MPI_COMM_WORLD,&nprocs);


  //Process command-line arguments
  unsigned int N;


  if (argc != 2) {

    if (my_rank==0)
    fprintf(stderr,"Please provide the following on the command line: N (total size of array)\n");  
    
    MPI_Finalize();
    exit(0);
  }

  sscanf(argv[1],"%d",&N);

  if (N%nprocs!=0)
  {
    if (my_rank==0)
    fprintf(stderr,"Please enter a new value of N. N mod p !=0\n");      
    
    MPI_Finalize();
    exit(0);
  }

  
  
  //Global array (rank 0 allocates this)
  unsigned int * data;

  //Local array for the rank
  unsigned int * localData=(unsigned int *)malloc(sizeof(unsigned int)*(N/nprocs));
  
  if (my_rank==0)
  {
    data=(unsigned int *)malloc(sizeof(unsigned int)*N);
    //generate data on rank 0
    for (int i=0; i<N; i++)
    {
      data[i]=i%5; //generate 0, 1, 2, 3, 4
    }
  }


  //Write code here






  if (my_rank==0)
  printf("\nGlobal sum should be: %u",N*2);

  if (my_rank==0)
  {
    free(data);
  }
  
  free(localData);



  MPI_Finalize();

  return 0;
}