2.1.22.2.1.31 fft_fft_multiple_real

Description

computes the discrete Fourier transforms of iSequences sequences of iSize real data values. For forward FT, each output sequence is in Hermitian form; For backward FT, each input sequence is in Hermitian form.

Syntax

int fft_fft_multiple_real( int iSequences, int iSize, double * 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 input data sequences to be transformed, and the result of the Fourier transforms.

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 real data values stored in the first
//column successively. This piece of code computers the discrete Fourier transform.
//The result is output into the second column. An inverse transform is performed,
//and the result is output into the third column.

#include <..\originlab\fft.h>    
void TEST_fft_fft_multiple_real()
{
    int iSeq=3, iL=7, success;
    int n = iSeq*iL;
    Worksheet wks = Project.ActiveLayer();
    if(wks)
    {
        Dataset xx(wks, 0);
        Dataset aa(wks, 1);
        aa.SetSize(n);
        Dataset bb(wks, 2);
        bb.SetSize(n);
        
        vector x = xx;
        
        ///FT
        success = fft_fft_multiple_real(iSeq, iL, x);
        aa = x;
        
        ///IFT
        success = fft_fft_multiple_real(iSeq, iL, x, FFT_BACKWARD);
        bb = x;
    }
}

Remark

See Also

fft_fft_multiple_complex

Header to Include

fft.h

Reference