ifft on gpu returns wrong values
显示 更早的评论
I wanted to calculate a 2D FFT on a 3D array and then get the 2D IFFT back. I wanted to use the gpuArray to accelerate the implementation, and I am not sure why I am getting the wrong answer when I have the 3D array on the gpu. For example:
A = fft2(gpuArray(rand(10,10,5)));
A1 = ifft2(A);
A2 = ifft(ifft(A,[],2),[],1);
all(A1==A2,'all')
gpuArray logical
0
A1 = ifft2(gather(A));
A2 = ifft(ifft(gather(A),[],2),[],1);
all(A1==A2,'all')
logical
1
The reason that I used ifft(ifft(A,[],2),[],1) is that I am going to extend the code for a 4D array, and I could not use FFTn to perform a 3D FFT on the first three dimensions! But, when I wanted to get a 3D FFT and then a 3D IFFT using 1d FFT/IFFT, I noticed different GPU and CPU results. Would you please explain what I am doing wrong here?
采纳的回答
Your criterion for agreement is too strong:
A = fft2(gpuArray(rand(10,10,5)));
A1 = ifft2(A);
A2 = ifft(ifft(A,[],2),[],1);
>> max(abs(A1-A2),[],'all')
ans =
3.3529e-16
6 个评论
Mojtaba Zarei
2021-3-30
Matt J
2021-3-30
No, I think that is the fastest.
Walter Roberson
2021-3-30
there is ifft2() but it ends up doing multiple ifft. I seem to recall some transposes, so hypothetically it could be faster to transpose/permute to be ifft along the first dimension each time, might allow more efficient vectorization potentially.
Mojtaba Zarei
2021-3-30
Mojtaba Zarei
2021-3-30
更多回答（0 个）
类别
在 帮助中心 和 File Exchange 中查找有关 Transforms 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
