对于我正在编写的教程,我正在寻找一个"现实的"简单的例子,说明因无知SIMT/SIMD而造成的死锁.
我想出了这个片段,这似乎是一个很好的例子.
任何输入将不胜感激.
…
int x = threadID / 2;
if (threadID > x) {
value[threadID] = 42;
barrier();
}
else {
value2[threadID/2] = 13
barrier();
}
result = value[threadID/2] + value2[threadID/2];
我知道,既不是CUDA C也不是OpenCL C.
我试图以这种方式访问向量元素
struct point
{
unsigned int x;
unsigned int y;
};
...
thrust::device_vector<point> devPoints(hPoints.begin(), hPoints.end());
for(thrust::device_vector<point>::iterator iter = devPoints.begin(); iter != devPoints.end(); iter++)
{
std::cout << iter->x << " " << iter->y << " " << std::endl; (1)
}
device_vector已正确初始化.我收到以下错误:
error: expression must have pointer type (at 1)
error: no suitable user-defined conversion from "const thrust::detail::normal_iterator<thrust::device_ptr<point>>" to "thrust::device_ptr<point>" exists
detected during instantiation of "Pointer thrust::experimental::iterator_facade<Derived, Pointer, Value, Space, Traversal, Reference, Difference>::operator->() const [with Derived=thrust::detail::normal_iterator<thrust::device_ptr<point>>, Pointer=thrust::device_ptr<point>, Value=point, Space=thrust::detail::cuda_device_space_tag, Traversal=thrust::random_access_traversal_tag, Reference=thrust::device_reference<point>, Difference=ptrdiff_t]" …当我将一个对象作为const引用传递给另一个对象时,是否有副本？我总是假设,因为我通过引用传递了对象,成员对象本身实际上是我传入的对象而不是副本.我做了一个测试程序,导致传入的引用对象在范围的末尾被销毁,但它没有像我预期的那样崩溃.这是一个等待发生的错误还是被复制的对象？
#include <iostream>
#include <string>
class Something
{
public:
Something(const std::string& str) : mStr(str) {}
const std::string& str() const
{
return mStr;
}
private:
std::string mStr;
};
int main()
{
Something* something;
{
std::string temp = "Testing.";
something = new Something(temp);
}
std::cout<<something->str()<<"\n";
delete something;
return 0;
}
该std :: string是否仍然有效或被删除？(在对象本身)
我有一个名为A的基类,包含一个字符串类型参数.
B类派生自A.
我定义类C有参数A*a,并将其分配给B.
在main函数中,我无法获取基类的字符串值,因为它在b解构时变为空白.
我希望它输出:
"Hello!"
"Hello!"
end
但输出是:
"Hello!"
end
这是我的代码:
class A {
public:
string str;
};
class B : public A {
public:
B(string _str) {
str = _str;
}
};
class C {
public:
A *a;
public:
void printOut() {
B b("Hello!");
a = &b;
cout << a->str << endl;
}
};
int main() {
C c;
c.printOut();
cout << c.a->str << endl;
cout << "end" << endl;
return 0;
}
我怎么处理它？
以下bash脚本的结果是输出中的"空行"
ssh dev@my_service <<EOF
START_SERVICE_TIME_IS_UP=124
echo $START_SERVICE_TIME_IS_UP
exit
EOF
无法理解为什么.我希望在输出中看到"124".远程服务器正在运行Red Hat linux.