07-14-2015 12:16 PM
can someone hepl me in simple question:
when i use traditional fft.vi there is a button that place DC component to the center of FFT, is there some "button" or simple solution to do it in cuFFT?
07-21-2015 01:20 AM
Is there any live person?
I think that all 85 views of this discussion was done by me:))
07-21-2015 07:41 AM
Not that I'm aware of but I haven't specifically hunted for this.
I believe the output of the cuFFT from the gpu toolkit starts at DC, goes to your highest frequency (sample rate/2), then goes back to DC.
I think it would be fairly trivial to write a VI that rearranges your array so that it flips the first half and second half of the array seperattely then puts them back to gether to accomplish your goal. Keep in mind that (I believe this is correct) there will be two values that represent the DC, the first and last value in you FFT output, thought I think simply added those togther would double the DC component for a normalized FFT.
07-21-2015 09:55 AM
thank you very much for your answer,
you are right that it could be done like you said, but I want to do it in the GPU memory. I have to do FFT spatial filtration that is: step1.FFT-->step2. spatial filtration in frequency domain -->step3. inverse FFT. If i should get out of GPU memory for the step number 2 i will lose all the time that I win with help of GPU (it's long procedure to transfer data in/out GPU memory)