libdspl-2.0/dspl/src/math_stat/mean.c

123 wiersze
3.4 KiB
C
Czysty Wina Historia

This file contains ambiguous Unicode characters!

This file contains ambiguous Unicode characters that may be confused with others in your current locale. If your use case is intentional and legitimate, you can safely ignore this warning. Use the Escape button to highlight these characters.

/*
* Copyright (c) 2015-2024 Sergey Bakhurin
* Digital Signal Processing Library [http://dsplib.org]
*
* This file is part of DSPL.
*
* is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* DSPL is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Foobar. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "dspl.h"
#ifdef DOXYGEN_ENGLISH
/*! ****************************************************************************
\ingroup SPEC_MATH_STAT_GROUP
\brief Calculates the mean of the input vector `x`
Function calculates the mean value
\f[
m = \frac{1}{n}\sum_{i = 0}^{n-1} x(i)
\f]
\param[in] x
Pointer to the real input vector `x`. \n
Vector size is `[n x 1]`. \n \n
\param[in] n
Size of input vector `x`. \n \n
\param[out] m
Pointer to the variable which keeps vector `x` mean value.\n
Memory must be allocated. \n \n
`RES_OK` if function calculates successfully,
else \ref ERROR_CODE_GROUP "code error".
Example:
\code{.cpp}
double a[5] = {0.0, 1.0, 2.0, 3.0, 4.0};
double m;
mean(a, 5, &m);
printf("\n\n Mean value: %8.1f\n", m);
\endcode
As result the variable `m` will keep value `2`.
\author Sergey Bakhurin www.dsplib.org
***************************************************************************** */
#endif
#ifdef DOXYGEN_RUSSIAN
/*! ****************************************************************************
\ingroup SPEC_MATH_STAT_GROUP
\brief Выборочная оценка математического ожидания вещественного вектора `x`
Функция рассчитывает оценку математического ожидания
\f[
m = \frac{1}{n} \sum_{i = 0}^{n-1} x(i)
\f]
\param[in] x
Указатель на вещественный вектор `x`. \n
Размер вектора `[n x 1]`. \n \n
\param[in] n
Размер входного вектора `x`. \n \n
\param[out] m
Указатель на адрес памяти, в который сохранить
рассчитанное значение математического ожидания вектора `x`. \n
Память должна быть выделена. \n \n
\return
`RES_OK` если функция выполнена успешно. \n
В противном случае \ref ERROR_CODE_GROUP "код ошибки".
Пример:
\code{.cpp}
double a[5] = {0.0, 1.0, 2.0, 3.0, 4.0};
double m;
mean(a, 5, &m);
printf("\n\n Mean value: %8.1f\n", m);
\endcode
В результате в переменную `m` будет записано значение `2`.
\author Бахурин Сергей. www.dsplib.org
***************************************************************************** */
#endif
int DSPL_API mean(double* x, int n, double* m)
{
int k;
double sum;
if(!x || !m)
return ERROR_PTR;
if(n<1)
return ERROR_SIZE;
sum = x[0];
for(k = 1; k < n; k++)
sum += x[k];
(*m) = sum / (double)n;
return RES_OK;
}