OpenMP求完数

源代码：
 1 #include "stdafx.h"  //必须写在首行，因为其前面的include都会被忽略
 2 #include "omp.h"  
 3 #include <Windows.h>  
 4 #include "time.h" 
 5 #include <iostream>
 6 #include <set>
 7 using namespace std;
 8 
　　//串行方式
 9 set<int> FinishedNumber(int n)
10 {
11     set<int> s;
12     for (int i = 2; i <= n; i++)
13     {
14         int maxv = (int)(sqrt(double(i)) + 1);
15         int sum = 1;
16         for (int j = 2; j<maxv; j++)
17         if (i%j == 0)
18             sum += j + i / j;
19         if (sum == i)
20             s.insert(i);
21     }
22     return s;
23 }
24 

　　//并行方式
25 set<int> FinishedNumber(int n, int p)
26 {
27     set<int> s;
28     omp_set_num_threads(p);
29 #pragma omp parallel  
30 #pragma omp for  
31     for (int i = 2; i <= n; i++)
32     {
33         int maxv = (int)(sqrt(double(i)) + 1);
34         int sum = 1;
35         for (int j = 2; j<maxv; j++)
36         if (i%j == 0)
37             sum += j + i / j;
38         if (sum == i)
39             s.insert(i);
40     }
41     return s;
42 }
43 
44 void Test(int step, int count)
45 {
46     /*int step=100000;
47     int count=5;*/
48     for (int i = 1; i <= count; i++)
49     {
50         int n = i*step;
51         clock_t start_Serial = clock();
52 
53         set<int> result = FinishedNumber(n);
54         printf("n=%d以内的所有完数为：
", n);
55         for (set<int>::iterator it = result.begin(); it != result.end(); it++)
56         {
57             /*cout<<*it<<endl;*/
58             printf("%d
", *it);
59         }
60 
61         clock_t end_Serial = clock();
62         double timeCollapsedSerial = end_Serial - start_Serial;
63         printf("n=%d, 串行方式运行耗时：%f
", n, timeCollapsedSerial);
64 
65         int p = 0;
66         double timeCollapsedParallel = 0;
67         for (int power = 0; power<6; power++)
68         {
69             p = pow(2, power);
70             clock_t start_Parallel = clock();
71             FinishedNumber(n, p);
72             clock_t end_Parallel = clock();
73             timeCollapsedParallel = end_Parallel - start_Parallel;
74             float accelerationRate = timeCollapsedSerial / timeCollapsedParallel;
75             printf("n=%d, p=%d, 并行方式运行耗时: %f,加速比: %.3f
", n, p, timeCollapsedParallel, accelerationRate);
76         }
77 
78         printf("
");
79     }
80 }
81 int _tmain(int argc, _TCHAR* argv[])
82 {
83     int step = 1000 * 1000;
84     int count = 5;
85     Test(step, count);
86     system("pause");
87 }
运行结果：