Shift zero-frequency component to center of spectrum

`Y = fftshift(`

rearranges
a Fourier transform `X`

)`X`

by shifting the zero-frequency
component to the center of the array.

If

`X`

is a vector, then`fftshift`

swaps the left and right halves of`X`

.If

`X`

is a matrix, then`fftshift`

swaps the first quadrant of`X`

with the third, and the second quadrant with the fourth.If

`X`

is a multidimensional array, then`fftshift`

swaps half-spaces of`X`

along each dimension.