kopia lustrzana https://github.com/Dsplib/libdspl-2.0
136 wiersze
2.8 KiB
C
136 wiersze
2.8 KiB
C
/*
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* Copyright (c) 2015-2019 Sergey Bakhurin
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* Digital Signal Processing Library [http://dsplib.org]
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*
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* This file is part of libdspl-2.0.
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*
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* is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* DSPL is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with Foobar. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <stdlib.h>
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#include <math.h>
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#include "dspl.h"
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/******************************************************************************
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Real vector DFT
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*******************************************************************************/
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int DSPL_API dft(double* x, int n, complex_t *y)
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{
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int k;
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int m;
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double divn;
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double phi;
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if(!x || !y)
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return ERROR_PTR;
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if(n<1)
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return ERROR_SIZE;
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divn = 1.0 / (double)n;
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for(k = 0; k < n; k++)
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{
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RE(y[k]) = IM(y[k]) = 0.0;
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for(m = 0; m < n; m++)
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{
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phi = -M_2PI * divn * (double)k * (double)m;
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RE(y[k]) += x[m] * cos(phi);
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IM(y[k]) += x[m] * sin(phi);
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}
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}
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return RES_OK;
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}
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/******************************************************************************
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Complex vector DFT
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*******************************************************************************/
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int DSPL_API dft_cmplx(complex_t* x, int n, complex_t *y)
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{
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int k;
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int m;
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double divn;
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double phi;
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complex_t e;
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if(!x || !y)
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return ERROR_PTR;
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if(n<1)
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return ERROR_SIZE;
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divn = 1.0 / (double)n;
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for(k = 0; k < n; k++)
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{
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RE(y[k]) = IM(y[k]) = 0.0;
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for(m = 0; m < n; m++)
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{
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phi = -M_2PI * divn * (double)k * (double)m;
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RE(e) = cos(phi);
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IM(e) = sin(phi);
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RE(y[k]) += CMRE(x[m], e);
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IM(y[k]) += CMIM(x[m], e);
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}
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}
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return RES_OK;
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}
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/******************************************************************************
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Complex vector DFT
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*******************************************************************************/
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int DSPL_API idft_cmplx(complex_t* x, int n, complex_t *y)
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{
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int k;
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int m;
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double divn;
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double phi;
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complex_t e;
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if(!x || !y)
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return ERROR_PTR;
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if(n<1)
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return ERROR_SIZE;
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divn = 1.0 / (double)n;
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for(k = 0; k < n; k++)
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{
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RE(y[k]) = IM(y[k]) = 0.0;
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for(m = 0; m < n; m++)
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{
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phi = M_2PI * divn * (double)k * (double)m;
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RE(e) = cos(phi);
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IM(e) = sin(phi);
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RE(y[k]) += CMRE(x[m], e);
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IM(y[k]) += CMIM(x[m], e);
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}
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RE(y[k]) /= (double)n;
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IM(y[k]) /= (double)n;
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}
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return RES_OK;
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}
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