MKL FFT bin zero real and imaginary parts

[pedro-erencia]

Sometimes I get bins with zero on real and imaginary parts. I,.e I'm doing an FFT of floats of 20480 samples of a 16K tone sampled at 1.024 Msps, thus 50 Hz resolution per bin. The bin 9920, which corresponds to 496K is 0+0i.

The rest of the 10240 bins seem correct. 

I've done the FFT on Octave and that bin should fit without problems on a float. 

What can cause this?

NOTE:

Curiosly enough, the failing bin is the symmetric with regards to the 16K tone, that is, the 16K tone is at bin 320, and the 9920 is the 320th bin starting from the right.

[MRajesh_intel]

Hi,

Thanks for posting your query.

Can you please share a minimal reproducer code along with OS, MKL version used, so that we can try to reproduce the scenario from our end?

Regards

Rajesh.

[pedro-erencia]

Hi,

I've made another post this morning with the information to reproduce the case.

Best Regards.

[MRajesh_intel · Accepted solution]

Hi,

Since this is a duplicate thread of https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/MKL-FFT-bin-zero-real-and-imaginary-parts-part-II/m-p/1296917#M31708.

Closing this thread for now and continuing the discussion in the above thread. We will no longer respond to this thread. If you require any additional assistance from Intel, please start a new thread. Any further interaction in this thread will be considered community only.

Have a Good day.

Regards

Rajesh