实验4 pi 的计算(5)

并行计算的pi的多种计算方法的实验

} printf("wall clock time = %f\n", endwtime-startwtime); fflush(stdout ); }

}

MPI_Finalize();

return 0;

}

(2)第二种方法

double f(double);

double f(double a)

{

}

int _tmain(intargc, char* argv[])

{

int done = 0, n, myid, numprocs, i,source=0,count=1; double PI25DT = 3.141592653589793238462643;

doublemypi, pi, h, sum, x;

doublestartwtime = 0.0, endwtime;

MPI_Init(&argc,&argv);

MPI_Comm_size(MPI_COMM_WORLD,&numprocs);

MPI_Comm_rank(MPI_COMM_WORLD,&myid);

while (!done)

{ { fflush(stdout); { } startwtime = MPI_Wtime(); fprintf(stdout, "No number entered; quitting\n" ); n = 0; if (myid == source) fprintf(stdout, "Enter the number of intervals: (0 quits) "); if (scanf("%d",&n) != 1) int b=(int)a; return (1.0 / (1.0 + 2*a)); else return (-1.0/(1.0+2*a)); if(b%2==0)