FFT Kernels

[Lui_S_]

Hi everybody,

quick question:

https://software.intel.com/en-us/articles/fft-length-and-layout-advisor

states: "The Intel® MKL FFT implementation employs radix 2, 3, 4, 5, 7, 8, 11, 13, 16 kernels, and several other larger size kernels."

https://software.intel.com/en-us/articles/mkl-ipp-choosing-an-fft

states: "2,3,5,7,11 and 13 kernels (**) ** - Both libraries support arbitrary radix in optimized manner, that is O(N log N), but these specific radixes are better optimized than others. 

So are only the radixes 2,3,5,7,11 and 13 optimized or 2, 3, 4, 5, 7, 8, 11, 13, 16 and several other? I do not find the answer to that anywhere. And before I start optimizing and get a suboptimal result (because I didn't know better) - I thought I'd ask.

Thanks!

Lui

[Gennady_F_Intel]

FFT with radixes 2, 4, 8, 16 ..... (power of 2) are most well optimized for both of  MKL and IPP libs ..

[Lui_S_]

Thanks! This is really helpful!

Is IPP generally faster than MKL on the same "task"? So if I can use IPP - should I use IPP versus MKL? I am talking about FFTs. 

Have a nice weekend!

[Gennady_F_Intel]

we expected the same performance for IPP and MKL.

[Lui_S_]

Thanks a lot! This was really helpful!