dspl/dft__cmplx_8c_source.html

/*

* Copyright (c) 2015-2024 Sergey Bakhurin

* Digital Signal Processing Library [http://dsplib.org]

*

* This file is part of libdspl-2.0.

*

* is free software: you can redistribute it and/or modify

* it under the terms of the GNU Lesser    General Public License as published by

* the Free Software Foundation, either version 3 of the License, or

* (at your option) any later version.

*

* DSPL is distributed in the hope that it will be useful,

* but WITHOUT ANY WARRANTY; without even the implied warranty of

* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.    See the

* GNU General Public License for more details.

*

* You should have received a copy of the GNU Lesser General Public License

* along with Foobar.    If not, see <http://www.gnu.org/licenses/>.

*/


#include <stdlib.h>

#include <math.h>

#include "dspl.h"


#ifdef DOXYGEN_ENGLISH


#endif

#ifdef DOXYGEN_RUSSIAN


#endif

int DSPL_API dft_cmplx(complex_t* x, int n, complex_t* y)

{

    int k;

    int m;

    double divn;

    double phi;

    complex_t e;


    if(!x || !y)

        return ERROR_PTR;


    if(n<1)

        return ERROR_SIZE;


    divn = 1.0 / (double)n;


    for(k = 0; k < n; k++)

    {

        RE(y[k]) = IM(y[k]) = 0.0;

        for(m = 0; m < n; m++)

        {

            phi    = -M_2PI * divn * (double)k * (double)m;

            RE(e) = cos(phi);

            IM(e) = sin(phi);

            RE(y[k]) += CMRE(x[m], e);

            IM(y[k]) += CMIM(x[m], e);

        }

    }

    return RES_OK;

}