[英]Thrust sort_by_key using tiled_range - not re-ordered
我在CUDA中使用帶有sort_by_key()的tiled_range,並且在sort_by_key期間鍵沒有重新排序,只是值...
例如:我有一個代表鍵的向量:
Keys 0 1 2 3 4 5
稍后使用tiled_range,我得到了帶有重復值的新矢量。
Keys 0 1 2 3 4 5 0 1 2 3 4 5
另一個代表值的向量:
values 0 3382 1863 470 311 2017 3382 0 251 1394 5651 257
我期望使用sort_by_keys重新排序鍵,如下所示:
Keys 0 0 1 1 2 2 3 3 4 4 5 5
Values 0 3382 3382 0 1863 251 470 1394 311 5651 2017 257
我的代碼以這種方式對鍵進行重新排序...
Keys 3 3 4 4 5 5 3 3 4 4 5 5
Values 0 3382 3382 0 1863 251 470 1394 311 5651 2017 257
我想知道,以這種方式重新訂購的原因可能是什么,我該怎么做才能獲得正確的訂單?
這是代碼:
#include <iterator>
#include <thrust/device_vector.h>
#include <thrust/host_vector.h>
#include <thrust/sort.h>
using namespace thrust::placeholders;
template<typename Iterator>
class tiled_range
//Code of tiled_range....
//
int main(void)
{
thrust::device_vector<int> data(6);
data[0] = 0; data[1] = 1; data[2] = 2; data[3] = 3; data[4] = 4; data[5] = 5;
thrust::device_vector<float> values(12);
values[0] = 0; values[6] = 3382;
values[1] = 3382; values[7] = 0;
values[2] = 1863; values[8] = 251;
values[3] = 470; values[9] = 1394;
values[4] = 311; values[10] = 5651;
values[5] = 2017; values[11] = 257;
tiled_range<thrust::device_vector<int>::iterator> keys(data.begin(), data.end(), 2);
std::cout << "Keys: " << std::endl;
thrust::copy(keys.begin(), keys.end(), std::ostream_iterator<int>(std::cout, " "));
std::cout << std::endl;
thrust::sort_by_key(keys.begin(), keys.end(), values.begin());
std::cout << "Keys: " << std::endl;
thrust::copy(keys.begin(), keys.end(), std::ostream_iterator<int>(std::cout, " "));
std::cout << std::endl;
std::cout << "Values: " << std::endl;
thrust::copy(values.begin(), values.end(), std::ostream_iterator<int> (std::cout, " "));
std::cout << std::endl;
return 0;
}
問題解決了! 我正在從以下位置檢查一些代碼: https : //groups.google.com/forum/#!msg/thrust-users/GqufHKoaizc/qx9cv-6xCg4J
我注意到他們將tiled_range的值復制到另一個向量中,在復制了這個新向量並將其放入sort_by_keys中之后,它對鍵和值進行了完美排序。 我仍然不明白為什么通過將tiled_range的迭代器作為sort_by_keys的輸入來導致上面的混亂……
這是代碼:
#include <iterator>
#include <thrust/device_vector.h>
#include <thrust/host_vector.h>
#include <thrust/sort.h>
using namespace thrust::placeholders;
template<typename Iterator>
class tiled_range
//Code of tiled_range....
//
int main(void)
{
thrust::device_vector<int> data(6);
data[0] = 0; data[1] = 1; data[2] = 2; data[3] = 3; data[4] = 4; data[5] = 5;
thrust::device_vector<float> values(12);
values[0] = 0; values[6] = 3382;
values[1] = 3382; values[7] = 0;
values[2] = 1863; values[8] = 251;
values[3] = 470; values[9] = 1394;
values[4] = 311; values[10] = 5651;
values[5] = 2017; values[11] = 257;
tiled_range<thrust::device_vector<int>::iterator> keys(data.begin(), data.end(), 2);
thrust::device_vector<int> keysN(keys.begin(), keys.end());
std::cout << "Keys: " << std::endl;
thrust::copy(keysN.begin(), keysN.end(), std::ostream_iterator<int>(std::cout, " "));
std::cout << std::endl;
thrust::sort_by_key(keysN.begin(), keysN.end(), values.begin());
std::cout << "Keys: " << std::endl;
thrust::copy(keys.begin(), keys.end(), std::ostream_iterator<int>(std::cout, " "));
std::cout << std::endl;
std::cout << "Values: " << std::endl;
thrust::copy(values.begin(), values.end(), std::ostream_iterator<int> (std::cout, " "));
std::cout << std::endl;
return 0;
}
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