/*
 *	This program has been tested with MPICH-1.2.5
 *	Run the program with BUFSIZE 31999,
 *	and 32000 to see the difference
 */
#include<stdio.h>			/*for input/output*/
#include<mpi.h>				/*for mpi routines*/

#define BUFSIZE 31999		/*The size of the messege being passed*/

main(int argc, char** argv)
{
	float *sendbuf, *recvbuf;
	int rank;				/*the rank of this process*/
	int tag = 0;
	MPI_Status status;		/*not important here*/

	sendbuf = (float *)malloc(sizeof(float)*BUFSIZE);
	recvbuf = (float *)malloc(sizeof(float)*BUFSIZE);

	MPI_Init(&argc, &argv);					/*Initializing mpi*/
	MPI_Comm_rank(MPI_COMM_WORLD, &rank);	/*Getting my rank*/

	if (rank == 0)
	{
		printf("Hello world! I am proc %d, sending to proc 1\n", rank);
		/*send to the proc 1*/
		MPI_Send(sendbuf, BUFSIZE, MPI_FLOAT, 1, tag, MPI_COMM_WORLD);

		/*recieve from proc 1*/
		MPI_Recv(recvbuf, BUFSIZE, MPI_FLOAT, 1, tag, MPI_COMM_WORLD, &status);
	}
	else if (rank == 1)
	{
		printf("Hello world! I am proc %d, sending to proc 0\n", rank);
		/*send to the proc 0*/
		MPI_Send(sendbuf, BUFSIZE, MPI_FLOAT, 0, tag, MPI_COMM_WORLD);

		/*recieve from the proc 0*/
		MPI_Recv(recvbuf, BUFSIZE, MPI_FLOAT, 0, tag, MPI_COMM_WORLD, &status);
	}
	printf("Proc %d finished!!\n", rank);
	free(sendbuf);
	free(recvbuf);
	MPI_Finalize();
	return 0;
}