dspl/ifft__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 <stdio.h>

#include <string.h>

#include <float.h>


#include "dspl.h"


#ifdef DOXYGEN_ENGLISH


#endif

#ifdef DOXYGEN_RUSSIAN


#endif

int DSPL_API ifft_cmplx(complex_t *x, int n, fft_t* pfft, complex_t* y)

{

    int err, k;

    double norm;


    if(!x || !pfft || !y)

        return ERROR_PTR;

    if(n<1)

        return ERROR_SIZE;


    err = fft_create(pfft, n);

    if(err != RES_OK)

        return err;


    memcpy(pfft->t1, x, n*sizeof(complex_t));

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

        IM(pfft->t1[k]) = -IM(pfft->t1[k]);


    err = fft_krn(pfft->t1, pfft->t0, pfft, n, 0);


    if(err!=RES_OK)

        return err;


    norm = 1.0 / (double)n;

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

    {

         RE(y[k]) =  RE(pfft->t0[k])*norm;

         IM(y[k]) = -IM(pfft->t0[k])*norm;

    }

    return RES_OK;

}