FFT using GPU Toolkit

[meteorite_man]

Hello Everyone ,

I am quite new to CUDA and FFT and as a first step I began with LabVIEW GPU toolkit. I have to use this toolkit due to batch processing of signals.

My issue concerns inverse FFT . To test FFT and inverse FFT I am simply generating a sine wave and passing it to the FFT function and then the FFT to inverse FFT . My setup is as follows :

FFT :

Data is originally in double , it is prepared into complex single.
Array is 1024*1024 where each row is a sine wave with a specific frequency.

FFT type : CUFFT_C2C
Batch Size : 1024
FFT size : 1024

Inverse FFT :

Spectrums is in Complex Single.
Array is 1024*1024 where each row is a sine wave with a specific frequency.

IFFT type : CUFFT_C2R
Batch Size : 1024
FFT size : 1024

Output spectrum from the FFT function is then passed onto inverse FFT , expecting to observe the same sine wave.

But I see something different , the first row of original sinewave and inverse FFT correspond . Rest of the signals don’t , they look weird.

PF images highlighting the issue :

Signal 0 :

Signal 13 : 

I have attached a snippet of my code . Hopefully , somebody can help me with this issue.

Have a nice day !