OpenMP #pragma omp parallel for並行化小探究，

OpenMP #pragma omp parallel for並行化小探究，

今天用了一下openmp，本人表示非常喜歡openmp的傻瓜化模式，匯入一個標頭檔

直接parallel for

#include <iostream>#include <omp.h>using namespace std;int main(){    //cout<<"Thread num == "<<omp_get_thread_num()<<endl;    #pragma omp parallel for num_threads(4)    for (int i=0;i<4;i++)    {        for (int j=0;j<4;j++)        {            printf("(%d,%d)",i,j);            cout<<" Thread num == "<<omp_get_thread_num()<<endl;        }    }}

可以看出這個編譯指導語句中的for是只對這句下一個for有用

用大括弧

#include <iostream>#include <omp.h>using namespace std;int main(){    //cout<<"Thread num == "<<omp_get_thread_num()<<endl;    #pragma omp parallel num_threads(4)    {        for (int i=0;i<4;i++)        {            for (int j=0;j<4;j++)            {                printf("(%d,%d)",i,j);                cout<<" Thread num == "<<omp_get_thread_num()<<endl;            }        }    }}

可以看出是所有4*4的迴圈完全打亂的情況

over~~~~~~