kopia lustrzana https://github.com/Dsplib/libdspl-2.0
156 wiersze
4.4 KiB
C
156 wiersze
4.4 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 "dspl.h"
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#ifdef DOXYGEN_ENGLISH
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/*! ****************************************************************************
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\ingroup SPEC_MATH_COMMON_GROUP
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\brief The logarithm function the complex vector argument `x`.
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Function calculates the logarithm function as: \n
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\f[
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\textrm{Ln}(x) = j \varphi + \ln(|x|),
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\f]
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here \f$\varphi\f$ - the complex number phase.
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\param[in] x
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Pointer to the argument vector `x`. \n
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Vector size is `[n x 1]`. \n \n
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\param[in] n
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Input vector `x` and the logarithm vector `y` size. \n \n
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\param[out] y
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Pointer to the output complex vector `y`,
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corresponds to the input vector `x`. \n
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Vector size is `[n x 1]`. \n
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Memory must be allocated. \n \n
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\return
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`RES_OK` if function calculated successfully. \n
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Else \ref ERROR_CODE_GROUP "code error". \n
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Example: \n
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\code{.cpp}
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complex_t x[3] = {{1.0, 2.0}, {3.0, 4.0}, {5.0, 6.0}};
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complex_t y[3];
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int k;
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log_cmplx(x, 3, y);
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for(k = 0; k < 3; k++)
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printf("log_cmplx(%.1f%+.1fj) = %.3f%+.3fj\n",
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RE(x[k]), IM(x[k]), RE(y[k]), IM(y[k]));
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\endcode
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\n
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Output is: \n
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\verbatim
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log_cmplx(1.0+2.0j) = 0.805+1.107j
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log_cmplx(3.0+4.0j) = 1.609+0.927j
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log_cmplx(5.0+6.0j) = 2.055+0.876j
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\endverbatim
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\author
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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 SPEC_MATH_COMMON_GROUP
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\brief Натуральный логарифм комплексного аргумента `x`.
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Функция рассчитывает значения натурального логарифма комплексного аргумента,
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заданного вектором `x` длины `n`: \n
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\f[
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\textrm{Ln}(x) = j \varphi + \ln(|x|),
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\f]
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где \f$\varphi\f$ --- фаза комплексного числа.
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\param[in] x
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Указатель на комплексный вектор аргумента логарифма. \n
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Размер вектора `[n x 1]`. \n \n
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\param[in] n
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Размер входного и выходного векторов `x` и `y`. \n \n
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\param[out] y
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Указатель на вектор значений комплексного логарифма,
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соответствующего входному вектору `x`. \n
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Размер массива `[n 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 значение функции рассчитано успешно. \n
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В противном случае \ref ERROR_CODE_GROUP "код ошибки": \n
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Например при выполнении следующего кода
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\code{.cpp}
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complex_t x[3] = {{1.0, 2.0}, {3.0, 4.0}, {5.0, 6.0}};
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complex_t y[3];
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int k;
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log_cmplx(x, 3, y);
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for(k = 0; k < 3; k++)
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printf("log_cmplx(%.1f%+.1fj) = %.3f%+.3fj\n",
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RE(x[k]), IM(x[k]), RE(y[k]), IM(y[k]));
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\endcode
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\n
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Результатом работы будет
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\verbatim
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log_cmplx(1.0+2.0j) = 0.805+1.107j
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log_cmplx(3.0+4.0j) = 1.609+0.927j
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log_cmplx(5.0+6.0j) = 2.055+0.876j
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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 log_cmplx(complex_t* x, int n, complex_t *y)
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{
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int k;
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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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for(k = 0; k < n; k++)
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{
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RE(y[k]) = 0.5 * log(ABSSQR(x[k]));
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IM(y[k]) = atan2(IM(x[k]), RE(x[k]));
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}
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return RES_OK;
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}
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