kopia lustrzana https://github.com/Dsplib/libdspl-2.0
200 wiersze
5.1 KiB
C
200 wiersze
5.1 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 <string.h>
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#include <math.h>
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#include "dspl.h"
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/*******************************************************************************
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Fourier Series Decomposition
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*******************************************************************************/
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int DSPL_API fourier_series_dec(double* t, double* s, int nt, double period,
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int nw, double* w, complex_t* y)
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{
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int k, m;
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double dw = M_2PI / period;
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complex_t e[2];
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if(!t || !s || !w || !y)
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return ERROR_PTR;
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if(nt<1 || nw < 1)
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return ERROR_SIZE;
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if(period <= 0.0)
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return ERROR_NEGATIVE;
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memset(y, 0 , nw*sizeof(complex_t));
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for(k = 0; k < nw; k++)
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{
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w[k] = (k - nw/2) * dw;
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RE(e[1]) = s[0] * cos(w[k] * t[0]);
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IM(e[1]) = -s[0] * sin(w[k] * t[0]);
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for(m = 1; m < nt; m++)
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{
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RE(e[0]) = RE(e[1]);
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IM(e[0]) = IM(e[1]);
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RE(e[1]) = s[m] * cos(w[k] * t[m]);
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IM(e[1]) = - s[m] * sin(w[k] * t[m]);
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RE(y[k]) += 0.5 * (RE(e[0]) + RE(e[1]))*(t[m] - t[m-1]);
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IM(y[k]) += 0.5 * (IM(e[0]) + IM(e[1]))*(t[m] - t[m-1]);
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}
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RE(y[k]) /= period;
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IM(y[k]) /= period;
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}
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if(!(nw%2))
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RE(y[0]) = RE(y[1]) = 0.0;
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return RES_OK;
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}
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/*******************************************************************************
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Fourier Series Decomposition for complex input signal
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*******************************************************************************/
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int DSPL_API fourier_series_dec_cmplx(double* t, complex_t* s, int nt,
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double period, int nw, double* w, complex_t* y)
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{
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int k, m;
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double dw = M_2PI / period;
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complex_t e[2];
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if(!t || !s || !w || !y)
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return ERROR_PTR;
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if(nt<1 || nw < 1)
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return ERROR_SIZE;
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if(period <= 0.0)
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return ERROR_NEGATIVE;
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memset(y, 0 , nw*sizeof(complex_t));
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for(k = 0; k < nw; k++)
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{
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w[k] = (k - nw/2) * dw;
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RE(e[1]) = RE(s[0]) * cos(w[k] * t[0]) +
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IM(s[0]) * sin(w[k] * t[0]);
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IM(e[1]) = -RE(s[0]) * sin(w[k] * t[0]) +
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IM(s[0]) * cos(w[k] * t[0]);
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for(m = 1; m < nt; m++)
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{
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RE(e[0]) = RE(e[1]);
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IM(e[0]) = IM(e[1]);
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RE(e[1]) = RE(s[m]) * cos(w[k] * t[m]) +
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IM(s[m]) * sin(w[k] * t[m]);
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IM(e[1]) = -RE(s[m]) * sin(w[k] * t[m]) +
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IM(s[m]) * cos(w[k] * t[m]);
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RE(y[k]) += 0.5 * (RE(e[0]) + RE(e[1]))*(t[m] - t[m-1]);
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IM(y[k]) += 0.5 * (IM(e[0]) + IM(e[1]))*(t[m] - t[m-1]);
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}
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RE(y[k]) /= period;
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IM(y[k]) /= period;
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}
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if(!(nw%2))
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RE(y[0]) = RE(y[1]) = 0.0;
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return RES_OK;
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}
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/*******************************************************************************
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Fourier Transform
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*******************************************************************************/
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int DSPL_API fourier_integral_cmplx(double* t, complex_t* s, int nt,
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int nw, double* w, complex_t* y)
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{
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int k, m;
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complex_t e[2];
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if(!t || !s || !w || !y)
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return ERROR_PTR;
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if(nt<1 || nw < 1)
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return ERROR_SIZE;
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memset(y, 0 , nw*sizeof(complex_t));
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for(k = 0; k < nw; k++)
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{
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RE(e[1]) = RE(s[0]) * cos(w[k] * t[0]) +
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IM(s[0]) * sin(w[k] * t[0]);
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IM(e[1]) = -RE(s[0]) * sin(w[k] * t[0]) +
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IM(s[0]) * cos(w[k] * t[0]);
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for(m = 1; m < nt; m++)
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{
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RE(e[0]) = RE(e[1]);
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IM(e[0]) = IM(e[1]);
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RE(e[1]) = RE(s[m]) * cos(w[k] * t[m]) +
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IM(s[m]) * sin(w[k] * t[m]);
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IM(e[1]) = -RE(s[m]) * sin(w[k] * t[m]) +
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IM(s[m]) * cos(w[k] * t[m]);
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RE(y[k]) += 0.5 * (RE(e[0]) + RE(e[1]))*(t[m] - t[m-1]);
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IM(y[k]) += 0.5 * (IM(e[0]) + IM(e[1]))*(t[m] - t[m-1]);
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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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Fourier Series Reconstruction
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*******************************************************************************/
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int DSPL_API fourier_series_rec(double* w, complex_t* s, int nw,
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double *t, int nt, complex_t* y)
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{
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int k, m;
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complex_t e;
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if(!t || !s || !w || !y)
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return ERROR_PTR;
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if(nt<1 || nw < 1)
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return ERROR_SIZE;
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memset(y, 0, nt*sizeof(complex_t));
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for(k = 0; k < nw; k++)
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{
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for(m = 0; m < nt; m++)
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{
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RE(e) = cos(w[k] * t[m]);
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IM(e) = sin(w[k] * t[m]);
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RE(y[m]) += CMRE(s[k], e);
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IM(y[m]) += CMIM(s[k], e);
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}
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}
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return RES_OK;
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}
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