openmp

openmp编程报错：

error: work-sharing region may not be closely nested inside of work-sharing, ‘critical’, ‘order ’, ‘master’, explicit ‘task’ or ‘task loop’ region

stackoverflow:
A worksharing region may not be closely nested inside a worksharing, explicit TASK, CRITICAL, ORDERED, or MASTER region.
（工作共享区域可能不能紧密地嵌套在工作共享、显式任务、关键、有序或主区域中。）

错误用法：

#pragma omp parallel for [clase] 
{
   #pragma omp single 
   { 
    do_something 
    } 
   loop() 
} 

分析：并行化嵌套使用错误，par_for下已经建立共享区，不能类似嵌套使用共享区。

正确用法：

#pragma omp parallel 
{
   #pragma omp single 
    { 
    do_something 
    } 
  #pragma omp for 
    loop() 
}