Question

我正在尝试使用OpenMP进行线程化，因为它是跨平台的。但是，当循环运行时，我无法解决如何在并行继续后生成代码？它基本上只是并行执行第一个循环但从未进入第二个非并行循环？

int main() {
    #pragma omp parallel 
        while(1) {
            Sleep(4000);
            printf("doing work in thread %d, nthreads %d\n", omp_get_thread_num(), omp_get_num_threads());
        }


    while (1) {
        Sleep(4000);
        printf("Hello from main %d, nthreads %d\n", omp_get_thread_num(), omp_get_num_threads());
    }
}

Answer 1

我认为你可以在你的omp并行块中将其中一个线程作为特殊线程

int main() {
    #pragma omp parallel 
        if(omp_get_thread_num()==0){
             while(1) {
                Sleep(4000);
               printf("Hello from main %d, nthreads %d\n", omp_get_thread_num(), omp_get_num_threads());
             }
        }else{
             while(1) {
                Sleep(4000);
                printf("doing work in thread %d, nthreads %d\n", omp_get_thread_num(), omp_get_num_threads());
             }
         }
    }
}

如果没有更多详细信息，很难判断天气是否有意义。

您也可以使用sections。例如：http://bisqwit.iki.fi/story/howto/openmp/#Sections：

#pragma omp parallel // starts a new team
{
   //Work0(); // this function would be run by all threads.

   #pragma omp sections // divides the team into sections
   { 
     // everything herein is run only once.
     { Work1(); }
     #pragma omp section
     { Work2();
       Work3(); }
     #pragma omp section
     { Work4(); }
   }

   //Work5(); // this function would be run by all threads.
}

您可以执行嵌套重新授权：OpenMP: What is the benefit of nesting parallelizations?

OpenMP运行线程但继续main

1 个答案: