kopia lustrzana https://github.com/Dsplib/libdspl-2.0
123 wiersze
2.5 KiB
C
123 wiersze
2.5 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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Chebyshev polynomials of the first kind
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*******************************************************************************/
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int DSPL_API cheby_poly1(double* x, int n, int ord, double* y)
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{
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int k, m;
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double t[2];
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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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if(ord<0)
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return ERROR_POLY_ORD;
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if(ord==0)
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{
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for(k = 0; k < n; k++)
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{
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y[k] = 1.0;
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}
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return RES_OK;
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}
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if(ord==1)
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{
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memcpy(y, x, n*sizeof(double));
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return RES_OK;
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}
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for(k = 0; k < n; k++)
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{
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m = 2;
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t[1] = x[k];
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t[0] = 1.0;
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while(m <= ord)
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{
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y[k] = 2.0 * x[k] *t[1] - t[0];
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t[0] = t[1];
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t[1] = y[k];
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m++;
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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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Chebyshev polynomials of the second kind
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*******************************************************************************/
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int DSPL_API cheby_poly2(double* x, int n, int ord, double* y)
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{
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int k, m;
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double t[2];
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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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if(ord<0)
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return ERROR_POLY_ORD;
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if(ord==0)
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{
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for(k = 0; k < n; k++)
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{
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y[k] = 1.0;
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}
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return RES_OK;
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}
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if(ord==1)
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{
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for(k = 0; k < n; k++)
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{
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y[k] = 2.0*x[n];
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};
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return RES_OK;
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}
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for(k = 0; k < n; k++)
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{
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m = 2;
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t[1] = 2.0*x[n];
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t[0] = 1.0;
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while(m <= ord)
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{
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y[k] = 2.0 * x[k] *t[1] - t[0];
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t[0] = t[1];
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t[1] = y[k];
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m++;
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}
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}
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return RES_OK;
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}
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