gctl_examples/examples/dynamic_stddev_ex.cpp
2024-09-10 20:19:20 +08:00

81 lines
2.8 KiB
C++

/********************************************************
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* ╚██████╔╝╚██████╗ ██║ ███████╗
* ╚═════╝ ╚═════╝ ╚═╝ ╚══════╝
* Geophysical Computational Tools & Library (GCTL)
*
* Copyright (c) 2022 Yi Zhang (yizhang-geo@zju.edu.cn)
*
* GCTL is distributed under a dual licensing scheme. You can redistribute
* it and/or modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation, either version 2
* of the License, or (at your option) any later version. You should have
* received a copy of the GNU Lesser General Public License along with this
* program. If not, see <http://www.gnu.org/licenses/>.
*
* If the terms and conditions of the LGPL v.2. would prevent you from using
* the GCTL, please consider the option to obtain a commercial license for a
* fee. These licenses are offered by the GCTL's original author. As a rule,
* licenses are provided "as-is", unlimited in time for a one time fee. Please
* send corresponding requests to: yizhang-geo@zju.edu.cn. Please do not forget
* to include some description of your company and the realm of its activities.
* Also add information on how to contact you by electronic and paper mail.
******************************************************/
#include "gctl/core.h"
#include "gctl/algorithm.h"
int main(int argc, char const *argv[])
{
gctl::array<double> all_data(1000);
gctl::random(all_data, 0.0, 2.0);
// 计算均值和方差
double mean = 0, stddev = 0;
for (int i = 0; i < all_data.size(); i++)
{
mean += all_data[i];
}
mean /= all_data.size();
for (int i = 0; i < all_data.size(); i++)
{
stddev += pow(all_data[i] - mean, 2.0);
}
stddev = sqrt(stddev/all_data.size());
std::cout << "mean = " << mean << ", stddev = " << stddev << std::endl;
// 计算前900个的均值和方差 然后动态计算最后100次
mean = 0;
stddev = 0;
for (int i = 0; i < 900; i++)
{
mean += all_data[i];
}
mean /= 900;
for (int i = 0; i < 900; i++)
{
stddev += pow(all_data[i] - mean, 2.0);
}
stddev = sqrt(stddev/900);
std::cout << "mean = " << mean << ", stddev = " << stddev << std::endl;
double new_mean;
int count = 900;
for (int i = 0; i < 100; i++)
{
stddev = gctl::dynamic_stddev(stddev, count, mean, all_data[900 + i], new_mean);
mean = new_mean;
std::cout << i << " mean = " << mean << ", stddev = " << stddev << std::endl;
count++;
}
return 0;
}