# InvFFT

Advanced Analysis Library Only

AnalysisLibErrType InvFFT (double arrayXReal[], double arrayXImg[], int numberOfElements);

## Purpose

| Note This function is obsolete. National Instruments recommends that you use CxInvFFTEx instead.

Calculates the inverse Fast Fourier Transform (FFT) of the complex data.

Let X = x + jy be the complex array:

Y = FFT–1(X)

InvFFT performs the operation in place and overwrites the input arrays.

### Example

/* Generate two arrays with random numbers and calculate the inverse Fast Fourier Transform. */
double x[256], y[256];
int n;
n = 256;
Uniform (n, 17, x);
Uniform (n, 17, y);
InvFFT (x, y, n);

## Parameters

Input
Name | Type | Description
numberOfElements | integer | Number of elements in the input arrays.
Output
Name | Type | Description
arrayXReal | double-precision array | On input, the real part of the complex array used to compute the inverse FFT. On output, the real part of inverse FFT. This operation is performed in place, meaning the values in this array are overwritten.
arrayXImg | double-precision array | On input, the imaginary part of the complex array used to compute the inverse FFT. On output, the imaginary part of inverse FFT. This operation is performed in place, meaning the values in this array are overwritten.

## Return Value

Name | Type | Description
status | AnalysisLibErrType | A value that specifies the type of error that occurred. Refer to analysis.h for definitions of these constants.