# 2.1.22.2.1.21 fft_fft_2d_complex

## Description

computes the two-dimensional discrete Fourier transform or inverse Fourier transform of a bivariate sequence of complex data values.

## Syntax

int fft_fft_2d_complex( int iSizeX, int iSizeY, double * vSigReal, double * vSigImag, FFT_SIGN iSign = FFT_FORWARD )

## Parameters

iSizeX
[input] the number of rows of the bivariate data sequence.
iSizeY
[input] the number of columns of the bivariate data sequence.
vSigReal
[modify] the real parts of the original signal to be transformed for input, and the real part of the corresponding elements of the computed transform for output.
vSigImag
[modify] the imaginary parts of the original signal to be transformed for input, and the imaginary part of the corresponding elements of the computed transform for output.
iSign
[input] the transformation to carry out
= FFT_FORWARD: FFT (by default)
= FFT_BACKWARD: IFFT.

## Return

Returns 0 for success or error codes for failure.

## Examples

EX1

//Assume the current Worksheet has 7 columns, the first two columns contain 7*8 data each.
//The first column is the real part of the original 2d complex data and the second column
//is the imaginary part. This piece of code reads in a sequence of these 7*8 complex
//data values and put the result of the two-dimensional discrete Fourier transform of
//the original data into the third and fourth columns. The third column is the real part
//and the fourth column is the imaginary part. Then inverse Fourier transform is performed,
//and the result is output into the fifth and the sixth columns.

#include <..\originlab\fft.h>
void TEST_fft_fft_2d_complex()
{
int n=7, m=8, k=n*m, success;
//Attach two Datasets to these 2 columns
Worksheet wks = Project.ActiveLayer();
if(wks)
{
Dataset xx(wks, 0);
Dataset yy(wks, 1);
Dataset aa(wks, 2);
aa.SetSize(k);
Dataset bb(wks, 3);
bb.SetSize(k);
Dataset cc(wks, 4);
cc.SetSize(k);
Dataset dd(wks, 5);
dd.SetSize(k);

vector x = xx, y = yy;

///FT
success = fft_fft_2d_complex(n, m, x, y);
//put the result back to the current worksheet, the third and the fourth column.
aa = x;
bb = y;

///IFT
success = fft_fft_2d_complex(n, m, x, y, FFT_BACKWARD);
//put the result back to the current worksheet, the fifth and the sixth column.
cc = x;
dd = y;
}
}