计算CUDA数组中的数字的出现次数 [英] Counting occurences of numbers in a CUDA array

问题描述

我有一个无符号整数数组存储在GPU与CUDA（通常 1000000 元素）。我想计算数组中每个数字的出现。只有几个不同的数字（约 10 ），但这些数字可以从1到 1000000 。关于 9/10 的数字是 0 ，我不需要他们的计数。结果如下所示：

I have an array of unsigned integers stored on the GPU with CUDA (typically 1000000 elements). I would like to count the occurence 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 occurences
15 -> 412 occurences

我有一个实现使用 atomicAdd s，但是它太慢了（很多线程写入到同一个地址）。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

您可以通过首先对数字进行排序，

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 thrust :: reduce_by_key 。它也通常比基于原子的ad hoc binning快得多。以下是示例。

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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