# Fourier on chosen dimensions

I have a data set DATA in 4 dimensions $$A \times B \times C \times D$$ and I want to use the Fourier function net only on the 2 and the 4 dimensions, $$B$$ and $$D$$. When i'm applying Fourier[DATA], it applies fft on all dimensions, which I don't want. How can I use the Fourier function to do fft only on my chosen dimensions?

• Do you mean that you want to apply a 2D Fourier transformation to the 2D slice corresponding to a[[1]] and d[[1]], then apply another 2D transform to the 2D slice with a[[1]] and d[[2]], etc? – bill s Mar 7 '19 at 14:57
• No, i want to do 1D FFT in the B dimension and oin the D dimension – david Mar 7 '19 at 17:01
• What are the dimensions of A, B, C, and D? – bill s Mar 7 '19 at 17:07
• A=2,B=8,C=32,D=1024 – david Mar 8 '19 at 15:20
• Hi david - I'm confused. Take the D dimension with 1024 points. If your data is 4-dimensional, then for each of the other dimensions, there is a different set of 1024 points: when considering a[[1]], b[[1]], c[[1]] there is one set of Ds, when a[[2]], b[[1]], c[[1], there is another set of Ds etc. So are you trying to take 2*8*32 different 1D FFTs of the D-data? – bill s Mar 8 '19 at 20:49