OpenMP求完数

源代码：

 #include "stdafx.h"  //必须写在首行，因为其前面的include都会被忽略

 #include "omp.h"

 #include <Windows.h>

 #include "time.h"

 #include <iostream>

 #include <set>

 using namespace std;

 
　　//串行方式

 set<int> FinishedNumber(int n)

 {

     set<int> s;

     for (int i = ; i <= n; i++)

     {

         int maxv = (int)(sqrt(double(i)) + );

         int sum = ;

         for (int j = ; j<maxv; j++)

         if (i%j == )

             sum += j + i / j;

         if (sum == i)

             s.insert(i);

     }

     return s;

 }

　　//并行方式

 set<int> FinishedNumber(int n, int p)

 {

     set<int> s;

     omp_set_num_threads(p);

 #pragma omp parallel

 #pragma omp for

     for (int i = ; i <= n; i++)

     {

         int maxv = (int)(sqrt(double(i)) + );

         int sum = ;

         for (int j = ; j<maxv; j++)

         if (i%j == )

             sum += j + i / j;

         if (sum == i)

             s.insert(i);

     }

     return s;

 }

 void Test(int step, int count)

 {

     /*int step=100000;

     int count=5;*/

     for (int i = ; i <= count; i++)

     {

         int n = i*step;

         clock_t start_Serial = clock();

         set<int> result = FinishedNumber(n);

         printf("n=%d以内的所有完数为：\n", n);

         for (set<int>::iterator it = result.begin(); it != result.end(); it++)

         {

             /*cout<<*it<<endl;*/

             printf("%d\n", *it);

         }

         clock_t end_Serial = clock();

         double timeCollapsedSerial = end_Serial - start_Serial;

         printf("n=%d, 串行方式运行耗时：%f\n", n, timeCollapsedSerial);

         int p = ;

         double timeCollapsedParallel = ;

         for (int power = ; power<; power++)

         {

             p = pow(, power);

             clock_t start_Parallel = clock();

             FinishedNumber(n, p);

             clock_t end_Parallel = clock();

             timeCollapsedParallel = end_Parallel - start_Parallel;

             float accelerationRate = timeCollapsedSerial / timeCollapsedParallel;

             printf("n=%d, p=%d, 并行方式运行耗时: %f,加速比: %.3f\n", n, p, timeCollapsedParallel, accelerationRate);

         }

         printf("\n");

     }

 }

 int _tmain(int argc, _TCHAR* argv[])

 {

     int step =  * ;

     int count = ;

     Test(step, count);

     system("pause");

 }

运行结果：