Please could any one give me the output of this program and explain why: mpirub -np 2 ./prog.o
#include "mpi.h"
#include <math.h>
#include <stdio.h>
int main(int argc, char *argv[])
{
int done = 0, n, myid, numprocs, i, rc;
double PI25DT = 3.141592653589793238462643;
double mypi, pi, h, sum, x, a;
MPI_Init(&argc,&argv);
MPI_Comm_size(MPI_COMM_WORLD,&numprocs);
MPI_Comm_rank(MPI_COMM_WORLD,&myid);
printf("\n My Id is %d \n",myid);
while (!done)
{
if (myid == 0) { /* I am the boss */
printf("Enter the number of intervals: (0 quits) ");
scanf("%d",&n);
}
printf("Broadcasting\n");
MPI_Bcast(&n, 1, MPI_INT, 0, MPI_COMM_WORLD);
printf("Finish\n");
if (n == 0) break;
h= 1.0 / (double) n; sum = 0.0;
for (i = myid + 1; i <= n; i += numprocs) {
x = h * ((double)i - 0.5);
sum += 4.0 / (1.0 + x*x);
}
mypi = h * sum;
MPI_Reduce(&mypi, &pi, 1, MPI_DOUBLE, MPI_SUM,
0, MPI_COMM_WORLD);
if (myid == 0)
printf("pi is approximately %.16f, Error is .16f\n", pi, fabs(pi - PI25DT));
} MPI_Finalize(); return 0; }