﻿ILMath.ifftnsym Method (InArray(complex)) ILMathifftnsym Method (InArraycomplex) ILNumerics Ultimate VS Documentation
ILNumerics - Technical Application Development
Inverse fast fourier transform (n-D)

[ILNumerics Computing Engine]

Namespace: ILNumerics
Assembly: ILNumerics.Computing (in ILNumerics.Computing.dll) Version: 5.3.0.0 (5.3.7131.2749)
Syntax

```public static RetArray<double> ifftnsym(
InArray<complex> A
)```

#### Parameters

A
Type: ILNumericsInArraycomplex
Input array, n-D, complex hermitian (frequency domain)

#### Return Value

Type: RetArrayDouble
Transformation result
Remarks

The n-dimensional inverse transformation is computed for the n-dimensional array A. This is equivalent to repeatedly (inplace) computing one dimensional transformations along all dimensions 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.

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

No check is made for A being hermitian! If A is not hermitian (by means of round-off errors), the result will be wrong!

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 in how to tune/configure and select dedicated native libraries.

[ILNumerics Computing Engine]