kopia lustrzana https://github.com/Dsplib/libdspl-2.0
76 wiersze
1.7 KiB
C
76 wiersze
1.7 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 DSPL.
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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 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 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 <stdio.h>
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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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#ifdef DOXYGEN_ENGLISH
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#endif
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#ifdef DOXYGEN_RUSSIAN
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#endif
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int DSPL_API ellip_modulareq(double rp, double rs, int ord, double *k)
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{
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double ep, es, ke, kp, t, sn = 0.0;
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int i, L, r;
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if(rp < 0 || rp == 0)
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return ERROR_FILTER_RP;
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if(rs < 0 || rs == 0)
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return ERROR_FILTER_RS;
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if(ord < 1)
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return ERROR_FILTER_ORD;
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if(!k)
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return ERROR_PTR;
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ep = sqrt(pow(10.0, rp*0.1)-1.0);
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es = sqrt(pow(10.0, rs*0.1)-1.0);
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ke = ep/es;
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ke = sqrt(1.0 - ke*ke);
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r = ord % 2;
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L = (ord-r)/2;
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kp = 1.0;
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for(i = 0; i < L; i++)
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{
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t = (double)(2*i+1) / (double)ord;
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ellip_sn(&t, 1, ke, &sn);
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sn*=sn;
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kp *= sn*sn;
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}
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kp *= pow(ke, (double)ord);
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*k = sqrt(1.0 - kp*kp);
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return RES_OK;
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}
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