2.1.22.2.1.11 fftw_fft_multiple_complex

1 Description
2 Syntax
3 Parameters
4 Return
5 Examples
6 Remark
7 See Also
8 Header to Include
9 Reference

Description

Computes the discrete Fourier transforms of iSequences sequences of iSize complex data values

Syntax

int fftw_fft_multiple_complex( int iSequences, int iSize, d_complex * vSig, FFT_SIGN iSign = FFT_FORWARD )

Parameters

iSequences: [input] the number of sequences
iSize: [input] the number of data values in each sequence.
vSig: [modify] the complex data sequences for input and the result data after fourier transformation 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 3 sequences of complex data values stored in the first
//two columns. The first column contains the real part, and the second column imaginary
//part. This piece of code computers the discrete Fourier transform. The result is
//output into the third and the fourth columns. An inverse transform is performed,
//and the result is output into the fifth and the sixth columns.

#include <..\originlab\fft.h>

void TEST_fftw_fft_multiple_complex()
{
	int iSeq=3, iL=7, success;
	int n = iSeq*iL;
	Worksheet wks = Project.ActiveLayer();
	if(wks)
	{
	    Dataset xx(wks, 0);
	    Dataset yy(wks, 1);
	    Dataset aa(wks, 2);
	    aa.SetSize(n);
	    Dataset bb(wks, 3);
	    bb.SetSize(n);
	    Dataset cc(wks, 4);
	    cc.SetSize(n);  
	    Dataset dd(wks, 5);
	    dd.SetSize(n);          
	                
	    vector x = xx, y = yy;
	            
	    //make a complex vector by x and y
	    vector<complex> vc;
	    vc.MakeComplex(x, y);
	    
	    ///FT
	    success = fftw_fft_multiple_complex(iSeq, iL, vc);
	    vc.GetReal(x);
	    vc.GetImaginary(y);
	    aa = x;
	    bb = y;
	                
	    ///IFT
	    success = fftw_fft_multiple_complex(iSeq, iL, vc, FFT_BACKWARD);
	    vc.GetReal(x);
	    vc.GetImaginary(y);
	    cc = x;
	    dd = y;
    }
}