并行计算的pi的多种计算方法的实验

MPI_Bcast(&n, count, MPI_INT, source, MPI_COMM_WORLD); if (n == 0)

done = 1;

else {

} sum = 0.0; for(int j=0;j<=n;j++) mypi = 4.0*sum; // h是º?宽¨ª度¨¨。¡ê这a样¨´得Ì?到Ì?sum += f(j); // 计?算?长¡è条¬?的Ì?高?。¡ê 面?积y。¡ê MPI_Reduce(&mypi, &pi, count, MPI_DOUBLE, MPI_SUM, source, if (myid == source) { printf("pi is approximately %.16f, Error is %.16f\n", pi, fabs(pi - endwtime = MPI_Wtime(); // 主¡Â进?程¨¬计?时º¡À。¡ê MPI_COMM_WORLD); // 所¨´有®D进?程¨¬的Ì?工¡è作Á¡Â汇?总Á¨¹ PI25DT)); printf("wall clock time = %f\n", endwtime-startwtime); fflush(stdout ); }

}

MPI_Finalize();

return 0;

}

(3)第三种方法

#include"stdafx.h"

#include"mpi.h"

#include<iostream>

#include"windows.h"

#include<math.h>

double f(double);

double t(double);

double f(int a)

{

int b=(int)a; doublenum; double sum=0.0;