[ILNumerics Computing Engine]

**Namespace:**ILNumerics

**Assembly:**ILNumerics.Computing (in ILNumerics.Computing.dll) Version: 5.5.0.0 (5.5.7503.3146)

#### Parameters

- A
- Type: ILNumericsInArraycomplex

Complex hermitian input array (frequency domain)

#### Return Value

Type: RetArrayDoubleReal array with the inverse transformation of complex, hermitian A.

Since a transform of complex hermitian input data results in the output having the imaginary part equal to zero, only the real part is returned for efficiency reasons.

One way to create a hermitian array is to (forward) transform a real array.

No check is made for A being hermitian! If A is not hermitian (within round-off errors), the result will be incorrect!

The transformation is computed for the first 2 dimensions, regardless of those dimensions being singleton or non-singleton. If A is an n-d array, the transformation is repeated for trailing dimensions of A respectively.

The two dimensional transformation is equivalent to repeatedly transforming the columns and after that transforming the rows of A. However, using this function may be of magnitudes faster than using 1D transformations. This depends on the algorithm and API provided by the underlying native library.

The forward fourier transform and the inverse fourier transform of a given data array A are mathematically equivalent. It's only a scaling factor which is needed to make sure, A equals ifft(fft(A)). That scaling is introduced in the inverse transform.

The transformation is computed by use of the native library which currently is set up for your processor and OS version. The underlying library is automatically choosen at ILNumerics startup and accessed via the static member ILMath.FFT. See the online documentation for more details on how to tune/configure and select dedicated native libraries.

[ILNumerics Computing Engine]