topic Re: Any way to do array reduction ? in Intel® oneAPI DPC++/C++ Compiler

Any way to do array reduction ?

baranovsky — Wed, 06 Apr 2022 03:16:24 GMT

Single variable reduction seems to be possible with sycl::reduction interface.

According to "SYCL 2020 Specification (revision 4)", array reduction will be achieved via reduction interface with std::span, which does not exist in current oneAPI release.

template <typename T, typename Extent, typename BinaryOperation> __unspecified__ reduction(span<T, Extent> vars, const T& identity, BinaryOperation combiner, const property_list &propList = {});

Is there any way to do array reduction at this point?

Thank you in advance for your help!

Re: Any way to do array reduction ?

NoorjahanSk_Intel — Fri, 08 Apr 2022 09:36:18 GMT

Hi,

Thanks for reaching out to us.

Yes, you are correct array reduction will be achieved via reduction interface with std::span, and is not supported in current oneAPI release. We will discuss with the Developer team and come back with an update soon.

Thanks & Regards,

Noorjahan

Re:Any way to do array reduction ?

cw_intel — Mon, 11 Apr 2022 06:50:05 GMT

Hi,

DPC++ supports built-in reduction operations, for more information, please refer to this guide https://www.intel.com/content/www/us/en/develop/documentation/oneapi-gpu-optimization-guide/top/kernels/reduction.html

Thanks

Re: Any way to do array reduction ?

baranovsky — Wed, 20 Apr 2022 00:02:12 GMT

Thank you everyone!
I'm going to implement array reduction by using the built-in reduction operation multiple time.
I will move to the std::span interface, once it is supported!

Re:Any way to do array reduction ?

cw_intel — Fri, 29 Apr 2022 03:10:36 GMT

Thanks for accepting our solution. If you need any additional information, please post a new question as this thread will no longer be monitored by Intel.

Re: Any way to do array reduction ?

baranovsky — Wed, 13 Jul 2022 12:27:48 GMT

I found that ruduction of sycl::float2/3/4/8/16 and sycl::double2/3/4/8/16 does the trick for me.

I hope arbitrary-size array reduction will be supported soon!