Inverse fast Fourier transform

`X = ifft(`

computes
the inverse discrete Fourier transform of `Y`

)`Y`

using
a fast Fourier transform algorithm. `X`

is the same
size as `Y`

.

If

`Y`

is a vector, then`ifft(Y)`

returns the inverse transform of the vector.If

`Y`

is a matrix, then`ifft(Y)`

returns the inverse transform of each column of the matrix.If

`Y`

is a multidimensional array, then`ifft(Y)`

treats the values along the first dimension whose size does not equal 1 as vectors and returns the inverse transform of each vector.

The

`ifft`

function tests whether the vectors in`Y`

are conjugate symmetric. A vector`v`

is conjugate symmetric when it equals`conj(v([1,end:-1:2]))`

. If the vectors in`Y`

are conjugate symmetric, then the inverse transform computation is faster and the output is real.