maxmin

#include "mpi.h"
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <signal.h>

#define MYTAG 1
int rank, j;
double startwtime = 0.0, endwtime;

int main(int argc, char *argv[])
{
int total, n, size, i, dest;
double result;
MPI_Status status;

MPI_Init(&argc, &argv);
MPI_Comm_size(MPI_COMM_WORLD, &size);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);

double a[10][10];
total = 10;

if (rank == 0)
n = total / size + 1;
MPI_Bcast(&n, 1, MPI_INT, 0, MPI_COMM_WORLD);

//a = new double[total];


if (rank == 0) {
for (dest=1; dest < size; dest++) {
for (i = 0; i < n; i++) {
for(int j = 0; j < total;j++) {
a[i][j] = 5;
}

}
MPI_Send(a, n, MPI_DOUBLE, dest, MYTAG, MPI_COMM_WORLD);
}
n = total - n*(size-1);

} else {
MPI_Recv(a, n, MPI_DOUBLE, 0, MYTAG, MPI_COMM_WORLD, &status);
}

double max = a[0][0];
double min = a[0][0];
for (i = 0; i < n; i++) {
for(int j = 0; j < total;j++) {
if (a[i][j] < min)
min = a[i][j];
}
if (min > max)
max = min;
}

MPI_Reduce(&max, &result, 1, MPI_DOUBLE, MPI_MAX, 0, MPI_COMM_WORLD);

if (rank == 0) {
printf("Answer is %.4f\n", result);
}

MPI_Finalize();
return 0;
}