#include <stdio.h>

#include <stdlib.h>

#include "mpi.h"

#include <math.h>



/*

** start of main

*/

int main(int argc, char *argv[])

{

	int niter = 100000000;

	double x, y;

	int i, j, count = 0, mycount;

	double z, pi, z1;



	int nproc, nrank, proc;

	MPI_Status status;

	int master = 0;

	int tag = 123;



	MPI_Init(&argc, &argv);

	MPI_Comm_size(MPI_COMM_WORLD, &nproc);

	MPI_Comm_rank(MPI_COMM_WORLD, &nrank);



	mycount = 0;



         srand(time(NULL)*nrank);



	for (i=0; i
	{

		x = (double)rand() / (double)(RAND_MAX);

		y = (double)rand() / (double)(RAND_MAX);



		z = x*x + y*y;



		if (z <= 1)	mycount++;

	}



	/*

	** master : nrank = 0

	*/

	if (nrank == 0)

	{

		count = mycount;



		for (proc=1; proc
		{

			MPI_Recv(&mycount, 1, MPI_REAL, proc, tag, MPI_COMM_WORLD, &status);

			count += mycount;

		}



		pi = (double)4*count/(niter*nproc);



		printf("Processor %d sending results = %d to master process\n", nrank, mycount);

		printf("\n # of trials (cpu#: %d, time#: %d) = %d, estimate of pi is %g\n .", nproc, niter, niter*nproc, pi);



	}

	else {

		printf("Processor %d sending results = %d to master process\n", nrank, mycount);

		MPI_Send(&mycount, 1, MPI_REAL, master, tag, MPI_COMM_WORLD);

	}



	MPI_Finalize();



	return 0;

}