dspl/fft__create_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"

#include "dft.h"


#ifdef DOXYGEN_ENGLISH


#endif

#ifdef DOXYGEN_RUSSIAN


#endif

int DSPL_API fft_create(fft_t* pfft, int n)

{


    int n1, n2, addr, s, k, m, nw, err;

    double phi;

    s = n;

    nw = addr = 0;


    if(pfft->n == n)

        return RES_OK;


    while(s > 1)

    {

        n2 = 1;

        if(s%4096 == 0)  { n2 = 4096; goto label_size; }

        if(s%2048 == 0)  { n2 = 2048; goto label_size; }

        if(s%1024 == 0)  { n2 = 1024; goto label_size; }

        if(s%512  == 0)  { n2 =  512; goto label_size; }

        if(s%256  == 0)  { n2 =  256; goto label_size; }

        if(s%128  == 0)  { n2 =  128; goto label_size; }

        if(s% 64  == 0)  { n2 =   64; goto label_size; }

        if(s% 32  == 0)  { n2 =   32; goto label_size; }

        if(s% 16  == 0)  { n2 =   16; goto label_size; }

        if(s%  7  == 0)  { n2 =    7; goto label_size; }

        if(s%  8  == 0)  { n2 =    8; goto label_size; }

        if(s%  5  == 0)  { n2 =    5; goto label_size; }

        if(s%  4  == 0)  { n2 =    4; goto label_size; }

        if(s%  3  == 0)  { n2 =    3; goto label_size; }

        if(s%  2  == 0)  { n2 =    2; goto label_size; }


label_size:

        if(n2 == 1)

        {

            if(s > FFT_COMPOSITE_MAX)

            {

                err = ERROR_FFT_SIZE;

                goto error_proc;

            }


            nw += s;

            pfft->w = pfft->w ?

                      (complex_t*) realloc(pfft->w,  nw*sizeof(complex_t)):

                      (complex_t*) malloc(           nw*sizeof(complex_t));

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

            {

                phi = - M_2PI * (double)k / (double)s;

                RE(pfft->w[addr]) = cos(phi);

                IM(pfft->w[addr]) = sin(phi);

                addr++;

            }

            s = 1;

        }

        else

        {

            n1 = s / n2;

            nw += s;

            pfft->w = pfft->w ?

                      (complex_t*) realloc(pfft->w,    nw*sizeof(complex_t)):

                      (complex_t*) malloc(             nw*sizeof(complex_t));


            for(k = 0; k < n1; k++)

            {

                for(m = 0; m < n2; m++)

                {

                    phi = - M_2PI * (double)(k*m) / (double)s;

                    RE(pfft->w[addr]) = cos(phi);

                    IM(pfft->w[addr]) = sin(phi);

                    addr++;

                }

            }

        }

        s /= n2;

    }


    pfft->t0 = pfft->t0 ? (complex_t*) realloc(pfft->t0, n*sizeof(complex_t)):

                          (complex_t*) malloc(           n*sizeof(complex_t));


    pfft->t1 = pfft->t1 ? (complex_t*) realloc(pfft->t1, n*sizeof(complex_t)):

                          (complex_t*) malloc(           n*sizeof(complex_t));

    pfft->n = n;


    /* w32 fill */

    addr = 0;

    for(k = 0; k < 4; k++)

    {

        for(m = 0; m < 8; m++)

        {

            phi = - M_2PI * (double)(k*m) / 32.0;

            RE(pfft->w32[addr]) = cos(phi);

            IM(pfft->w32[addr]) = sin(phi);

            addr++;

        }

    }


    /* w64 fill */

    addr = 0;

    for(k = 0; k < 8; k++)

    {

        for(m = 0; m < 8; m++)

        {

            phi = - M_2PI * (double)(k*m) / 64.0;

            RE(pfft->w64[addr]) = cos(phi);

            IM(pfft->w64[addr]) = sin(phi);

            addr++;

        }

    }


    /* w128 fill */

    addr = 0;

    for(k = 0; k < 8; k++)

    {

        for(m = 0; m < 16; m++)

        {

            phi = - M_2PI * (double)(k*m) / 128.0;

            RE(pfft->w128[addr]) = cos(phi);

            IM(pfft->w128[addr]) = sin(phi);

            addr++;

        }

    }


    /* w256 fill */

    addr = 0;

    for(k = 0; k < 16; k++)

    {

        for(m = 0; m < 16; m++)

        {

            phi = - M_2PI * (double)(k*m) / 256.0;

            RE(pfft->w256[addr]) = cos(phi);

            IM(pfft->w256[addr]) = sin(phi);

            addr++;

        }

    }


    /* w512 fill */

    addr = 0;

    for(k = 0; k < 16; k++)

    {

        for(m = 0; m < 32; m++)

        {

            phi = - M_2PI * (double)(k*m) / 512.0;

            RE(pfft->w512[addr]) = cos(phi);

            IM(pfft->w512[addr]) = sin(phi);

            addr++;

        }

    }


    /* w1024 fill */

    if(pfft->w1024 == NULL)

    {

        pfft->w1024 = (complex_t*) malloc(1024 * sizeof(complex_t));

        addr = 0;

        for(k = 0; k < 32; k++)

        {

            for(m = 0; m < 32; m++)

            {

                phi = - M_2PI * (double)(k*m) / 1024.0;

                RE(pfft->w1024[addr]) = cos(phi);

                IM(pfft->w1024[addr]) = sin(phi);

                addr++;

            }

        }

    }


    /* w2048 fill */

    if(pfft->w2048 == NULL)

    {

        pfft->w2048= (complex_t*) malloc(2048 * sizeof(complex_t));

        addr = 0;

        for(k = 0; k < 32; k++)

        {

            for(m = 0; m < 64; m++)

            {

                phi = - M_2PI * (double)(k*m) / 2048.0;

                RE(pfft->w2048[addr]) = cos(phi);

                IM(pfft->w2048[addr]) = sin(phi);

                addr++;

            }

        }

    }


    /* w4096 fill */

    if(pfft->w4096 == NULL)

    {

        pfft->w4096= (complex_t*) malloc(4096 * sizeof(complex_t));

        addr = 0;

        for(k = 0; k < 16; k++)

        {

            for(m = 0; m < 256; m++)

            {

                phi = - M_2PI * (double)(k*m) / 4096.0;

                RE(pfft->w4096[addr]) = cos(phi);

                IM(pfft->w4096[addr]) = sin(phi);

                addr++;

            }

        }

    }


    return RES_OK;

error_proc:

    if(pfft->t0) free(pfft->t0);

    if(pfft->t1) free(pfft->t1);

    if(pfft->w)    free(pfft->w);

    pfft->n = 0;

    return err;

}