Note: This page has been translated by MathWorks. Click here to see

To view all translated materials including this page, select Country from the country navigator on the bottom of this page.

To view all translated materials including this page, select Country from the country navigator on the bottom of this page.

Multidimensional inverse fast Fourier transform

`X = ifftn(Y)`

`X = ifftn(Y,sz)`

`X = ifftn(___,symflag)`

`X = ifftn(`

returns
the multidimensional
discrete inverse Fourier transform of an N-D array using a
fast Fourier transform algorithm. The N-D inverse transform is equivalent
to computing the 1-D inverse transform along each dimension of `Y`

)`Y`

.
The output `X`

is the same size as `Y`

.

`X = ifftn(`

truncates `Y`

,`sz`

)`Y`

or
pads `Y`

with trailing zeros before taking the inverse
transform according to the elements of the vector `sz`

.
Each element of `sz`

defines the length of the corresponding
transform dimension. For example, if `Y`

is a 5-by-5-by-5
array, then `X = ifftn(Y,[8 8 8])`

pads each dimension
with zeros, resulting in an 8-by-8-by-8 inverse transform `X`

.

The

`ifftn`

function tests whether the vectors in an array`Y`

are conjugate symmetric in all dimensions. A vector`v`

is conjugate symmetric when the*i*th element satisfies`v(i) = conj(v([1,end:-1:2]))`

. If the vectors in`Y`

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