kopia lustrzana https://github.com/Dsplib/libdspl-2.0
200 wiersze
6.0 KiB
C
200 wiersze
6.0 KiB
C
/*
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* Copyright (c) 2015-2020 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 ARRAY_GROUP
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\fn int linspace(double x0, double x1, int n, int type, double* x)
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\brief Function fills a vector with `n` linearly spaced elements
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between `x0` and `x1`.
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Function supports two kinds of filling according to `type` parameter: \n
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Symmetric fill (parameter `type=DSPL_SYMMETRIC`): \n
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\f$x(k) = x_0 + k \cdot dx\f$,
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\f$dx = \frac{x_1 - x_0}{n-1}\f$, \f$k = 0 \ldots n-1.\f$
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Periodic fill (parameter `type=DSPL_PERIODIC`): \n
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\f$x(k) = x_0 + k \cdot dx\f$,
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\f$dx = \frac{x_1 - x_0}{n}\f$, \f$k = 0 \ldots n-1.\f$
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\param[in] x0
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Start point \f$x_0\f$. \n \n
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\param[in] x1
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End point \f$x_1\f$. \n \n
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\param[in] n
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Number of points `x` (size of vector `x`). \n \n
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\param[in] type
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Fill type: \n
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`DSPL_SYMMETRIC` --- symmetric, \n
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`DSPL_PERIODIC` --- periodic. \n \n
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\param[in,out] x
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Pointer to the output linearly spaced 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 returns successfully. \n
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Else \ref ERROR_CODE_GROUP "error code".
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\note
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Difference between symmetric and periodic filling we can
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understand from the follow examples. \n
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Example 1. Periodic fill.
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double x[5];
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linspace(0, 5, 5, DSPL_PERIODIC, x);
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\endcode
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Values in the vector `x` are:
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\verbatim
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0, 1, 2, 3, 4
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\endverbatim
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\n \n
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Example 2. Symmetric fill.
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\code{.cpp}
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double x[5];
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linspace(0, 5, 5, DSPL_SYMMETRIC, x);
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\endcode
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Values in the vector `x` are:
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\verbatim
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0, 1.25, 2.5, 3.75, 5
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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 ARRAY_GROUP
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\fn int linspace(double x0, double x1, int n, int type, double* x)
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\brief Функция заполняет массив линейно-нарастающими, равноотстоящими
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значениями от `x0` до `x1`
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Заполняет массив `x` длиной `n` значениями в диапазоне
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от \f$x_0\f$ до \f$x_1\f$. Функция поддерживает два типа заполнения
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в соответствии с параметром `type`: \n
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Симметричное заполнение согласно выражению (параметр `type=DSPL_SYMMETRIC`): \n
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\f$x(k) = x_0 + k \cdot dx\f$,
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\f$dx = \frac{x_1 - x_0}{n-1}\f$, \f$k = 0 \ldots n-1.\f$
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Периодическое заполнение (параметр `type=DSPL_PERIODIC`) согласно выражению: \n
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\f$x(k) = x_0 + k \cdot dx\f$,
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\f$dx = \frac{x_1 - x_0}{n}\f$, \f$k = 0 \ldots n-1.\f$
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\param[in] x0
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Начальное показателя \f$x_0\f$. \n \n
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\param[in] x1
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Конечное значение \f$x_1\f$. \n \n
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\param[in] n
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Количество точек массива `x`. \n \n
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\param[in] type
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Тип заполнения: \n
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`DSPL_SYMMETRIC` --- симметричное заполнение, \n
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`DSPL_PERIODIC` --- периодическое заполнение. \n \n
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\param[in,out] x
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Указатель на вектор равноотстоящих значений . \n
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Размер вектора `[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` --- функция выполнена успешно. \n
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В противном случае \ref ERROR_CODE_GROUP "код ошибки". \n \n
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\note
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Отличие периодического и симметричного заполнения можно
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понять из следующих примеров. \n
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Пример 1. Периодическое заполнение.
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\code{.cpp}
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double x[5];
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linspace(0, 5, 5, DSPL_PERIODIC, x);
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\endcode
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В массиве `x` будут лежать значения:
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\verbatim
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0, 1, 2, 3, 4
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\endverbatim
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\n \n
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Пример 2. Симметричное заполнение.
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\code{.cpp}
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double x[5];
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linspace(0, 5, 5, DSPL_SYMMETRIC, x);
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\endcode
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В массиве `x` будут лежать значения:
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\verbatim
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0, 1.25, 2.5, 3.75, 5
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\endverbatim
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\author
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Бахурин Сергей
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www.dsplib.org
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***************************************************************************** */
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#endif
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int DSPL_API linspace(double x0, double x1, int n, int type, double* x)
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{
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double dx;
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int k;
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if(n < 2)
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return ERROR_SIZE;
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if(!x)
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return ERROR_PTR;
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switch (type)
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{
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case DSPL_SYMMETRIC:
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dx = (x1 - x0)/(double)(n-1);
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x[0] = x0;
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for(k = 1; k < n; k++)
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x[k] = x[k-1] + dx;
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break;
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case DSPL_PERIODIC:
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dx = (x1 - x0)/(double)n;
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x[0] = x0;
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for(k = 1; k < n; k++)
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x[k] = x[k-1] + dx;
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break;
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default:
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return ERROR_SYM_TYPE;
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}
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return RES_OK;
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}
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