kopia lustrzana https://github.com/Dsplib/libdspl-2.0
287 wiersze
8.3 KiB
C
287 wiersze
8.3 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 <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "dspl.h"
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#ifdef DOXYGEN_ENGLISH
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/*! ****************************************************************************
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\ingroup IIR_FILTER_DESIGN_GROUP
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\fn int ratcompos( double* b, double* a, int n,
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double* c, double* d, int p,
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double* beta, double* alpha)
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\brief Rational composition
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Function calcultes composition \f$Y(s) = (H \circ F)(s) = H(F(s))\f$, here
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\f[
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H(s) = \frac{\sum\limits_{m = 0}^{n} b_m s^m}
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{\sum\limits_{k = 0}^{n} a_k s^k}, \quad
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F(s) = \frac{\sum\limits_{m = 0}^{p} d_m s^m}
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{\sum\limits_{k = 0}^{p} c_k s^k}, \quad
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Y(s) = \frac{\sum\limits_{m = 0}^{n p} \beta_m s^m}
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{\sum\limits_{k = 0}^{n p} \alpha_k s^k}
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\f]
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This function is using for filter frequency transform.
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\param[in] b
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Pointer to the \f$H(s)\f$ polynomial function
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numerator coefficients vector. \n
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Vector size is `[n+1 x 1]`. \n
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\n
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\param[in] a
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Pointer to the \f$H(s)\f$ polynomial function
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denominator coefficients vector. \n
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Vector size is `[n+1 x 1]`. \n
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\n
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\param[in] n
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Order of \f$H(s)\f$ numerator and denominator polynomials. \n
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\n
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\param[in] c
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Pointer to the \f$F(s)\f$ polynomial function
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numerator coefficients vector. \n
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Vector size is `[p+1 x 1]`. \n
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\n
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\param[in] d
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Pointer to the \f$F(s)\f$ polynomial function
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denominator coefficients vector. \n
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Vector size is `[p+1 x 1]`. \n
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\n
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\param[in] p
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Order of \f$F(s)\f$ numerator and denominator polynomials. \n
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\n
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\param[in,out] beta
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Pointer to the numerator coefficients vector of
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\f$Y(s) = (H \circ F)(s)\f$. \n
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Vector size is `[n*p+1 x 1]`. \n
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Memory must be allocated. \n
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\n
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\param[in,out] alpha
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Pointer to the denominator coefficients vector of
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\f$Y(s) = (H \circ F)(s)\f$. \n
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Vector size is `[n*p+1 x 1]`. \n
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Memory must be allocated. \n
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\n
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\return
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`RES_OK` if rational composition is calculated successfully. \n
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Else \ref ERROR_CODE_GROUP "code error".
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\author Sergey Bakhurin www.dsplib.org
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***************************************************************************** */
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#endif
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#ifdef DOXYGEN_RUSSIAN
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/*! ****************************************************************************
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\ingroup IIR_FILTER_DESIGN_GROUP
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\fn int ratcompos( double* b, double* a, int n,
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double* c, double* d, int p,
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double* beta, double* alpha)
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\brief Рациональная композиця
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Функция рассчитывает композицию вида \f$Y(s) = (H \circ F)(s) = H(F(s))\f$, где
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\f[
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H(s) = \frac{\sum\limits_{m = 0}^{n} b_m s^m}
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{\sum\limits_{k = 0}^{n} a_k s^k}, \quad
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F(s) = \frac{\sum\limits_{m = 0}^{p} d_m s^m}
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{\sum\limits_{k = 0}^{p} c_k s^k}, \quad
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Y(s) = \frac{\sum\limits_{m = 0}^{n p} \beta_m s^m}
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{\sum\limits_{k = 0}^{n p} \alpha_k s^k}
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\f]
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Функция рациональной композиции необходима для произведения частотных
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преобразований передаточных характеристик аналоговых и цифровых фильтров,
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а также для билинейного преобразования передаточных характеристик аналоговых
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фильтров в соответствующие передаточные характеристики цифровых фильтров.
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\param[in] b
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Указатель на вектор коэффициентов числителя функции \f$H(s)\f$. \n
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Размер вектора `[n+1 x 1]`. \n
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Память должна быть выделена. \n
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\n
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\param[in] a
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Указатель на вектор коэффициентов знаменателя функции \f$H(s)\f$. \n
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Размер вектора `[n+1 x 1]`. \n
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Память должна быть выделена. \n
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\n
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\param[in] n
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Порядок полиномов рациональной функции \f$H(s)\f$. \n
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\n
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\param[in] c
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Указатель на вектор коэффициентов числителя функции \f$F(s)\f$. \n
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Размер вектора `[p+1 x 1]`. \n
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Память должна быть выделена. \n
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\n
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\param[in] d
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Указатель на вектор коэффициентов знаменателя функции \f$F(s)\f$. \n
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Размер вектора `[p+1 x 1]`. \n
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Память должна быть выделена. \n
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\n
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\param[in] p
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Порядок полиномов рациональной
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функции \f$F(s)\f$. \n
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\n
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\param[in,out] beta
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Указатель на вектор коэффициентов
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числителя функции \f$Y(s) = (H \circ F)(s)\f$. \n
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Размер вектора `[n*p+1 x 1]`. \n
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Память должна быть выделена. \n
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\n
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\param[in,out] alpha
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Указатель на вектор коэффициентов знаменателя
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функции \f$Y(s) = (H \circ F)(s)\f$. \n
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Размер вектора `[n*p+1 x 1]`. \n
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Память должна быть выделена. \n
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\n
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\return
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`RES_OK` --- Рациональная композиция рассчитана успешно. \n
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В противном случае \ref ERROR_CODE_GROUP "код ошибки". \n
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\author Бахурин Сергей www.dsplib.org
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***************************************************************************** */
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#endif
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int DSPL_API ratcompos(double* b, double* a, int n,
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double* c, double* d, int p,
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double* beta, double* alpha)
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{
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int k2, i, k, pn, pd, ln, ld, k2s, nk2s;
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double *num = NULL, *den = NULL, *ndn = NULL, *ndd = NULL;
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int res;
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if (!a || !b || !c || !d || !beta || !alpha)
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{
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res = ERROR_PTR;
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goto exit_label;
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}
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if(n < 1 || p < 1)
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{
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res = ERROR_SIZE;
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goto exit_label;
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}
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k2 = (n*p)+1;
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k2s = k2*sizeof(double); /* alpha and beta size */
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nk2s = (n+1)*k2*sizeof(double); /* num, den, ndn and ndd size */
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num = (double*)malloc(nk2s);
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den = (double*)malloc(nk2s);
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ndn = (double*)malloc(nk2s);
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ndd = (double*)malloc(nk2s);
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memset(num, 0, nk2s);
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memset(den, 0, nk2s);
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memset(ndn, 0, nk2s);
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memset(ndd, 0, nk2s);
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num[0] = den[0] = 1.0;
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pn = 0;
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ln = 1;
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for(i = 1; i < n+1; i++)
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{
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res = conv(num+pn, ln, c, p+1, num+pn+k2);
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if(res!=RES_OK)
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goto exit_label;
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res = conv(den+pn, ln, d, p+1, den+pn+k2);
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if(res!=RES_OK)
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goto exit_label;
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pn += k2;
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ln += p;
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}
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pn = 0;
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pd = n*k2;
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ln = 1;
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ld = k2;
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for (i = 0; i < n+1; i++)
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{
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res = conv(num + pn, ln, den + pd, ld, ndn + i*k2);
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if(res!=RES_OK)
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goto exit_label;
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ln += p;
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ld -= p;
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pn += k2;
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pd -= k2;
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}
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for (i = 0; i < n+1; i++)
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{
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for (k = 0; k < k2; k++)
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{
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ndd[i*k2 + k] = ndn[i*k2 + k] * a[i];
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ndn[i*k2 + k] *= b[i];
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}
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}
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memset(alpha, 0, k2s);
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memset(beta, 0, k2s);
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for (k = 0; k < k2; k++)
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{
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for (i = 0; i < n+1; i++)
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{
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beta[k] += ndn[i*k2 + k];
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alpha[k] += ndd[i*k2 + k];
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}
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}
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res = RES_OK;
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exit_label:
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if(num)
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free(num);
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if(den)
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free(den);
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if(ndn)
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free(ndn);
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if(ndd)
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free(ndd);
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return res;
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}
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