What is the difference between the following two things:
make a 2-D Discrete Fourier Transform of a certain matrix A[p,p],
first reshape this matrix into a 1-D vector a[p^2,1], and compute the 1-D DFT of this vector?
Matlab shows the result is completely different, but I don't understand why, and is there a way to say how this two things can be equivalent? The second question is more important.