Difference between FFT(FFT(X)) ,FFT2(X) and FFT(X,[ ],2)

What is the difference between FFT(FFT(X)) ,FFT2(X) and FFT(X,[ ],2) ?

Answer 1

[dpb]

As the doc for fft2 shows

fft2(X) == fft(fft(X).')

or the 2D FFT is computed sequentially by 1D and then transposing and 1D the other way.

fft(X,[],2)

is just 1D FFT but by row (2nd dimension) instead of the default by column if X is 2D array.