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libdspl-2.0/dspl/src/fft.c

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8.6 KiB
C
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/*
* Copyright (c) 2015-2019 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 "dspl.h"
#include "dspl_internal.h"
/*******************************************************************************
COMPLEX vector IFFT
*******************************************************************************/
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;
}
/*******************************************************************************
Real vector FFT
*******************************************************************************/
int DSPL_API fft(double *x, int n, fft_t* pfft, complex_t* y)
{
int err;
if(!x || !pfft || !y)
return ERROR_PTR;
if(n<1)
return ERROR_SIZE;
err = fft_create(pfft, n);
if(err != RES_OK)
return err;
re2cmplx(x, n, pfft->t1);
return fft_krn(pfft->t1, y, pfft, n, 0);
}
/*******************************************************************************
COMPLEX vector FFT
*******************************************************************************/
int DSPL_API fft_cmplx(complex_t *x, int n, fft_t* pfft, complex_t* y)
{
int err;
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));
return fft_krn(pfft->t1, y, pfft, n, 0);
}
/*******************************************************************************
composite FFT kernel
*******************************************************************************/
int fft_krn(complex_t* t0, complex_t* t1, fft_t* p, int n, int addr)
{
int n1, n2, k, m, i;
complex_t *pw = p->w+addr;
complex_t tmp;
n1 = 1;
if(n%16== 0) { n1 = 16; goto label_size; }
if(n%7 == 0) { n1 = 7; goto label_size; }
if(n%5 == 0) { n1 = 5; goto label_size; }
if(n%4 == 0) { n1 = 4; goto label_size; }
if(n%3 == 0) { n1 = 3; goto label_size; }
if(n%2 == 0) { n1 = 2; goto label_size; }
label_size:
if(n1 == 1)
{
for(k = 0; k < n; k++)
{
RE(t1[k]) = IM(t1[k]) = 0.0;
for(m = 0; m < n; m++)
{
i = (k*m) % n;
RE(tmp) = CMRE(t0[m], pw[i]);
IM(tmp) = CMIM(t0[m], pw[i]);
RE(t1[k]) += RE(tmp);
IM(t1[k]) += IM(tmp);
}
}
}
else
{
n2 = n / n1;
if(n2>1)
{
memcpy(t1, t0, n*sizeof(complex_t));
transpose_cmplx(t1, n2, n1, t0);
}
if(n1 == 16)
for(k = 0; k < n2; k++)
dft16(t0+16*k, t1+16*k);
if(n1 == 7)
for(k = 0; k < n2; k++)
dft7(t0+7*k, t1+7*k);
if(n1 == 5)
for(k = 0; k < n2; k++)
dft5(t0+5*k, t1+5*k);
if(n1 == 4)
for(k = 0; k < n2; k++)
dft4(t0+4*k, t1+4*k);
if(n1 == 3)
for(k = 0; k < n2; k++)
dft3(t0+3*k, t1+3*k);
if(n1 == 2)
for(k = 0; k < n2; k++)
dft2(t0+2*k, t1+2*k);
if(n2 > 1)
{
for(k =0; k < n; k++)
{
RE(t0[k]) = CMRE(t1[k], pw[k]);
IM(t0[k]) = CMIM(t1[k], pw[k]);
}
transpose_cmplx(t0, n1, n2, t1);
for(k = 0; k < n1; k++)
{
fft_krn(t1+k*n2, t0+k*n2, p, n2, addr+n);
}
transpose_cmplx(t0, n2, n1, t1);
}
}
return RES_OK;
}
/*******************************************************************************
FFT create for composite N
*******************************************************************************/
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%16== 0) { n2 = 16; goto label_size; }
if(s%7 == 0) { n2 = 7; 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;
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;
}
/*******************************************************************************
FFT free
*******************************************************************************/
void DSPL_API fft_free(fft_t *pfft)
{
if(!pfft)
return;
if(pfft->w)
free(pfft->w);
if(pfft->t0)
free(pfft->t0);
if(pfft->t1)
free(pfft->t1);
memset(pfft, 0, sizeof(fft_t));
}
/*******************************************************************************
FFT shifting
*******************************************************************************/
int DSPL_API fft_shift(double* x, int n, double* y)
{
int n2, r;
int k;
double tmp;
double *buf;
if(!x || !y)
return ERROR_PTR;
if(n<1)
return ERROR_SIZE;
r = n%2;
if(!r)
{
n2 = n>>1;
for(k = 0; k < n2; k++)
{
tmp = x[k];
y[k] = x[k+n2];
y[k+n2] = tmp;
}
}
else
{
n2 = (n-1) >> 1;
buf = (double*) malloc(n2*sizeof(double));
memcpy(buf, x, n2*sizeof(double));
memcpy(y, x+n2, (n2+1)*sizeof(double));
memcpy(y+n2+1, buf, n2*sizeof(double));
free(buf);
}
return RES_OK;
}
/*******************************************************************************
FFT shifting for complex vector
*******************************************************************************/
int DSPL_API fft_shift_cmplx(complex_t* x, int n, complex_t* y)
{
int n2, r;
int k;
complex_t tmp;
complex_t *buf;
if(!x || !y)
return ERROR_PTR;
if(n<1)
return ERROR_SIZE;
r = n%2;
if(!r)
{
n2 = n>>1;
for(k = 0; k < n2; k++)
{
RE(tmp) = RE(x[k]);
IM(tmp) = IM(x[k]);
RE(y[k]) = RE(x[k+n2]);
IM(y[k]) = IM(x[k+n2]);
RE(y[k+n2]) = RE(tmp);
IM(y[k+n2]) = IM(tmp);
}
}
else
{
n2 = (n-1) >> 1;
buf = (complex_t*) malloc(n2*sizeof(complex_t));
memcpy(buf, x, n2*sizeof(complex_t));
memcpy(y, x+n2, (n2+1)*sizeof(complex_t));
memcpy(y+n2+1, buf, n2*sizeof(complex_t));
free(buf);
}
return RES_OK;
}
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