计算CUDA数组中数字的出现 [英] Counting occurrences of numbers in a CUDA array

问题描述

我使用CUDA（通常 1000000 个元素）在GPU上存储了一个无符号整数数组。我想计算数组中每个数字的出现。只有几个不同的数字（大约 10 ），但是这些数字的范围可以从1到 1000000 。大约 9/10 的数字是 0 ，我不需要计数。结果看起来像这样：

I have an array of unsigned integers stored on the GPU with CUDA (typically 1000000 elements). I would like to count the occurrence of every number in the array. There are only a few distinct numbers (about 10), but these numbers can span from 1 to 1000000. About 9/10th of the numbers are 0, I don't need the count of them. The result looks something like this:

58458 -> 1000 occurrences
15 -> 412 occurrences

我有一个使用 atomicAdd 的实现s，但是它太慢了（很多线程写入相同的地址）。有人知道快速/高效的方法吗？

I have an implementation using atomicAdds, but it is too slow (a lot of threads write to the same address). Does someone know of a fast/efficient method?

推荐答案

您可以先对数字进行排序，然后再进行

You can implement a histogram by first sorting the numbers, and then doing a keyed reduction.

最直接的方法是使用 thrust :: sort 然后使用 thrust :: reduce_by_key 。它通常也比基于原子的临时装箱要快得多。这是一个示例。

The most straightforward method would be to use thrust::sort and then thrust::reduce_by_key. It's also often much faster than ad hoc binning based on atomics. Here's an example.

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