#include "mpi.h"
#include "stdlib.h"
#define N 50000		/* N is the number of rounds */
#define B 250		/* B is the buffer size (1K) */
#define P 8             /* P is the number of players */
#define C 1             /* C indicates the amount of computation */

/* This is a ring program. */
/* It sends a message around N times among P entities. */

main(int argc, char *argv[])
{	int my_id, my_neighbor, prev_neighbor, rounds, values, comp;
	int ballarray[B];
	MPI_Status stat;

	if (MPI_Init(&argc, &argv)!=MPI_SUCCESS)
	{	printf("Sorry, that's an error.\n");
		exit(1);
	}

	MPI_Comm_rank(MPI_COMM_WORLD, &my_id);       /* Get rank */
	my_neighbor = (my_id+1)%P;
	prev_neighbor = (my_id+P-1)%P;
	
	/* First player starts the game */

	if (my_id==0)
	   MPI_Send(ballarray, B, MPI_INT, my_neighbor, 0, MPI_COMM_WORLD);

	/* Wait for the message then send it to next neighbor */

	for (rounds=0; rounds<N ;++rounds)
	{  MPI_Recv(ballarray, B,MPI_INT,prev_neighbor,0,MPI_COMM_WORLD,&stat);

	   /* Put random values into the array between 0-300 */

	   for (comp=0; comp<C; ++comp)
	         ballarray[comp] = (rand()%101) * ((rand()%3)+1);

	   /* printf("Player %d, Round %d.\n", my_id, rounds); */
	   MPI_Send(ballarray, B, MPI_INT, my_neighbor, 0, MPI_COMM_WORLD);
	}

	/* Game over -- don't return message */

	if (my_id==1)
	{  printf ("Game over after %d rounds, with %d players", N, P);
	   printf (" and a computation index of %d.\n", C);
	   MPI_Recv(ballarray, B,MPI_INT,prev_neighbor,0,MPI_COMM_WORLD,&stat);
	 }  
	MPI_Finalize();
}