kopia lustrzana https://github.com/Dsplib/libdspl-2.0
192 wiersze
5.0 KiB
C
192 wiersze
5.0 KiB
C
/*
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* Copyright (c) 2015-2024 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 "dspl.h"
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#ifdef DOXYGEN_ENGLISH
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/*! ****************************************************************************
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\ingroup FILTER_CONV_GROUP
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\brief Real vectors linear convolution.
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Function convolves two real vectors \f$ c = a * b\f$ length `na` and `nb`.
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The output convolution is a vector `c` with length equal to `na + nb - 1`.
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\param[in] a
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Pointer to the first vector `a`. \n
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Vector size is `[na x 1]`. \n \n
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\param[in] na
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Size of the first vector `a`. \n \n
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\param[in] b
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Pointer to the second vector `b`. \n
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Vector size is `[nb x 1]`. \n \n
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\param[in] nb
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Size of the second vector `b`. \n \n
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\param[out] c
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Pointer to the convolution output vector \f$ c = a * b\f$. \n
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Vector size is `[na + nb - 1 x 1]`. \n
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Memory must be allocated. \n \n
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\return `RES_OK` if convolution is calculated successfully. \n
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Else \ref ERROR_CODE_GROUP "code error".
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\note If vectors `a` and `b` are coefficients of two polynomials,
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then convolution of the vectors `a` and `b` returns polynomial product
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coefficients.
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Example:
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\code{.cpp}
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double ar[3] = {1.0, 2.0, 3.0};
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double br[4] = {3.0, -1.0, 2.0, 4.0};
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double cr[6];
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int n;
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conv(ar, 3, br, 4, cr);
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for(n = 0; n < 6; n++)
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printf("cr[%d] = %5.1f\n", n, cr[n]);
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\endcode
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\n
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Output:
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\verbatim
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cr[0] = 3.0
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cr[1] = 5.0
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cr[2] = 9.0
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cr[3] = 5.0
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cr[4] = 14.0
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cr[5] = 12.0
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\endverbatim
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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 FILTER_CONV_GROUP
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\brief Линейная свертка двух вещественных векторов
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Функция рассчитывает линейную свертку двух векторов \f$ c = a * b\f$.
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\param[in] a
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Указатель на первый вектор \f$a\f$. \n
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Размер вектора `[na x 1]`. \n \n
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\param[in] na
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Размер первого вектора. \n \n
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\param[in] b
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Указатель на второй вектор \f$b\f$. \n
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Размер вектора `[nb x 1]`. \n \n
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\param[in] nb
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Размер второго вектора. \n \n
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\param[out] c
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Указатель на вектор свертки \f$ c = a * b\f$. \n
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Размер вектора `[na + nb - 1 x 1]`. \n
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Память должна быть выделена. \n \n
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\return
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`RES_OK` если свертка расчитана успешно. \n
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В противном случае \ref ERROR_CODE_GROUP "код ошибки".
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\note
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Если вектора `a` и `b` представляют собой коэффициенты двух полиномов,
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то результат линейной свертки представляет собой коэффициенты произведения
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исходных полиномов.
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Пример использования функции:
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\code{.cpp}
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double ar[3] = {1.0, 2.0, 3.0};
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double br[4] = {3.0, -1.0, 2.0, 4.0};
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double cr[6];
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int n;
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conv(ar, 3, br, 4, cr);
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for(n = 0; n < 6; n++)
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printf("cr[%d] = %5.1f \n ", n, cr[n]);
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\endcode
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\n
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Результат работы:
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\verbatim
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cr[0] = 3.0
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cr[1] = 5.0
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cr[2] = 9.0
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cr[3] = 5.0
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cr[4] = 14.0
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cr[5] = 12.0
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\endverbatim
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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 conv(double* a, int na, double* b, int nb, double* c)
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{
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int k;
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int n;
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double *t;
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size_t bufsize;
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if(!a || !b || !c)
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return ERROR_PTR;
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if(na < 1 || nb < 1)
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return ERROR_SIZE;
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bufsize = (na + nb - 1) * sizeof(double);
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if((a != c) && (b != c))
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t = c;
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else
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t = (double*)malloc(bufsize);
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memset(t, 0, bufsize);
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for(k = 0; k < na; k++)
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for(n = 0; n < nb; n++)
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t[k+n] += a[k]*b[n];
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if(t!=c)
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{
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memcpy(c, t, bufsize);
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free(t);
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}
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return RES_OK;
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}
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