meanvar.hh
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/* -*- mia-c++ -*-
*
* This file is part of MIA - a toolbox for medical image analysis
* Copyright (c) Leipzig, Madrid 1999-2017 Gert Wollny
*
* MIA 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.
*
* This program 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 MIA; if not, see <http://www.gnu.org/licenses/>.
*
*/
#ifndef mia_core_meanvar_hh
#define mia_core_meanvar_hh
#include <map>
#include <cmath>
#include <mia/core/defines.hh>
NS_MIA_BEGIN
template <typename ForwardIterator>
std::pair<double, double> mean_var(ForwardIterator begin, ForwardIterator end)
{
std::pair<double, double> result;
result.first = 0.0;
result.second = 0.0;
size_t n = 0;
while (begin != end) {
const double help = *begin;
result.first += help;
result.second += help * help;
++n;
++begin;
}
if (n > 0)
result.first /= n;
if (n > 1)
result.second = sqrt((result.second - n * result.first * result.first) / (n - 1));
else
result.second = 0.0;
return result;
}
NS_MIA_END
#endif
defines.hh
NS_MIA_BEGIN
#define NS_MIA_BEGIN
conveniance define to start the mia namespace
Definition defines.hh:33
NS_MIA_END
#define NS_MIA_END
conveniance define to end the mia namespace
Definition defines.hh:36
mean_var
std::pair< double, double > mean_var(ForwardIterator begin, ForwardIterator end)
Definition meanvar.hh:42