并行计算期末试题-理工(2)

MPI_Finalize(); return 0; }

2、请分别用OpenMP和MPI并行编程的方法求PI的近似值。

#include #include

static long num_steps = 100000; double step;

#define NUM_THREADS 2 int main ()

{ int i;

double x, pi, sum[NUM_THREADS]; step = 1.0/(double) num_steps;

omp_set_num_threads(NUM_THREADS); // #pragma omp parallel {

double x; int id;

id = omp_get_thread_num();

for (i=id, sum[id]=0.0;i< num_steps; i=i+NUM_THREADS){// x = (i+0.5)*step;

sum[id] += 1.0/(1.0+x*x); } }

for(i=0, pi=0.0;i

{

pi += sum[i] * step; }

printf(“pi=%f”,pi);

}