OpenMP编程->同步机制

/* nowait用来取消栅障 */
void test12()
{
#pragma omp parallel
{
#pragma omp for nowait
for (int i = 0; i < 100; ++i)
{
std::cout << i << "+" << std::endl;
}
#pragma omp for
for (int j = 0; j < 100; ++j)
{
std::cout << j << "-" << std::endl;
}
}
}

/* 显式同步栅障  在barrier处进行了同步，然后执行后边的for循环。 */
void test13()
{
#pragma omp parallel
{
for (int i = 0; i < 100; ++i)
{
cout<<"ID "<<omp_get_thread_num()<<" ";
std::cout << i << "+" << std::endl;
}

#pragma omp barrier
for (int j = 0; j < 100; ++j)
{
cout<<"ID "<<omp_get_thread_num()<<" ";
std::cout << j << "-" << std::endl;
}
}
}

/* 声明对应的并行程序块只由主线程完成 */
void test14()
{
#pragma omp parallel
{
#pragma omp master
{
for (int j = 0; j < 10; ++j)
{
std::cout << j << "-" << std::endl;
}
}

std::cout << "This will printed twice." << std::endl;
}
}

/*  section用来指定不同的线程执行不同的部分  */
void test15()
{
#pragma omp parallel sections //声明该并行区域分为若干个section,section之间的运行顺序为并行的关系
{
#pragma omp section //第一个section,由某个线程单独完成
for (int i = 0; i < 5; ++i)
{
std::cout <<"i "<< i << "+" << std::endl;
cout<<"ID "<<omp_get_thread_num()<<" ";
}

#pragma omp section //第一个section,由某个线程单独完成
for (int j = 0; j < 5; ++j)
{
std::cout<<"j " << j << "-" << std::endl;
cout<<"ID "<<omp_get_thread_num()<<" ";
}
}
}