// GetWanShu.cpp : 定义控制台应用程序的入口点。
// #include "stdafx.h"
#include "omp.h"
#include <Windows.h>
#include "time.h"
//函数声明
void getWanShuBySection();
void getWanShu();
void getWanShuByReduction();
int _tmain(int argc, _TCHAR* argv[])
{
//串行实现求完数
clock_t start_LiXingLe=clock();
getWanShu();
clock_t end_LiXingLe=clock();
double chuanxingTime_LXL=end_LiXingLe-start_LiXingLe;
printf(" 串行时间为：%f\n",chuanxingTime_LXL);
//section 并行方法实现
getWanShuBySection();
//Reduction 并行方法实现
getWanShuByReduction(); //for 并行方法实现
omp_set_num_threads(4); start_LiXingLe=clock();
#pragma omp parallel
#pragma omp for for (int n = 1; n <= 10000; n++)
{
int sum = 0; for (int i = 1; i <= (n/2); i++) //除到原来一半就可以了
{
if (n % i == 0)
{
sum += i;
}
}
if (sum == n)
{
printf ("%d\n", sum);
}
} end_LiXingLe=clock();
double parallelTime_LXL=end_LiXingLe-start_LiXingLe;
printf(" for并行时间为 ：%f\n",parallelTime_LXL);
printf("for加速比为：%f\n",chuanxingTime_LXL/ parallelTime_LXL); return 0;
}
void getWanShuBySection(){ omp_set_num_threads(4); clock_t start_LiXingLe=clock();
#pragma omp parallel
{
#pragma omp sections
{ #pragma omp section
for (int n = 1; n < 2500; n++)
{
int sum = 0;
for (int i = 1; i <= (n/2); i++) //除到原来一半就可以了
{
if (n % i == 0)
{
sum += i;
}
}
if (sum == n)
{
printf ("%d\n", sum);
}
}
#pragma omp section
for (int n = 2500; n < 5000; n++)
{
int sum = 0;
for (int i = 1; i <= (n/2); i++) //除到原来一半就可以了
{
if (n % i == 0)
{
sum += i;
}
}
if (sum == n)
{
printf ("%d\n", sum);
}
}
#pragma omp section
for (int n = 5000; n <= 7500; n++)
{
int sum = 0;
for (int i = 1; i <= (n/2); i++) //除到原来一半就可以了
{
if (n % i == 0)
{
sum += i;
}
}
if (sum == n)
{
printf ("%d\n", sum);
}
}
#pragma omp section
for (int n = 7500; n <= 10000; n++)
{
int sum = 0;
for (int i = 1; i <= (n/2); i++) //除到原来一半就可以了
{
if (n % i == 0)
{
sum += i;
}
}
if (sum == n)
{
printf ("%d\n", sum);
}
} } } clock_t end_LiXingLe=clock();
printf(" section并行时间为 ：%d\n",end_LiXingLe-start_LiXingLe); }
void getWanShu(){ for (int n = 1; n <= 10000; n++)
{
int sum = 0;
for (int i = 1; i <= (n/2); i++) //除到原来一半就可以了
{
if (n % i == 0)
{
sum += i;
}
}
if (sum == n)
{
printf ("%d\n", sum);
}
} } void getWanShuByReduction(){ omp_set_num_threads(5); clock_t start_LiXingLe=clock();
for (int n = 1; n <= 10000; n++)
{
int sum = 0;
#pragma omp parallel for reduction(+:sum)
for (int i = 1; i <= (n/2); i++) //除到原来一半就可以了
{
if (n % i == 0)
{
sum += i;
}
}
if (sum == n)
{
printf ("%d\n", sum);
}
}
clock_t end_LiXingLe=clock();
printf(" reduction并行时间为 ：%d\n",end_LiXingLe-start_LiXingLe); }
运行结果：