MathUtil.h File Reference

#include <algorithm>
#include <iterator>
#include <numeric>
#include <vector>

Go to the source code of this file.

Functions
template<typename Container , typename T = typename std::decay<decltype(*std::begin(std::declval<Container>()))>::type>
T	standard_deviation (Container &&c)
template<typename Container , typename T = typename std::decay<decltype(*std::begin(std::declval<Container>()))>::type>
T	mean (Container &&c)
template<typename T >
T	median (std::vector< T > a)

Function Documentation

mean()

template<typename Container , typename T = typename std::decay<decltype(*std::begin(std::declval<Container>()))>::type>

T mean ( Container &&  c )

inline

{
    auto b = std::begin(c), e = std::end(c);
    auto size = std::distance(b, e);
    auto sum = std::accumulate(b, e, T());
    return sum / size;
}

Referenced by WorldSession::ComputeNewClockDelta(), and standard_deviation().

median()

template<typename T >

T median ( std::vector< T >  a )

inline

{
    size_t n = a.size();
    // If size of the arr[] is even
    if (n % 2 == 0)
    {
 
        // Applying nth_element
        // on n/2th index
        std::nth_element(a.begin(),
            a.begin() + n / 2,
            a.end());
 
        // Applying nth_element
        // on (n-1)/2 th index
        std::nth_element(a.begin(),
            a.begin() + (n - 1) / 2,
            a.end());
 
        // Find the average of value at
        // index N/2 and (N-1)/2
        return (T)(a[(n - 1) / 2]
            + a[n / 2])
            / 2.0;
    }
 
    // If size of the arr[] is odd
    else
    {
 
        // Applying nth_element
        // on n/2
        std::nth_element(a.begin(),
            a.begin() + n / 2,
            a.end());
 
        // Value at index (N/2)th
        // is the median
        return (T)a[n / 2];
    }
}

Referenced by WorldSession::ComputeNewClockDelta().

standard_deviation()

template<typename Container , typename T = typename std::decay<decltype(*std::begin(std::declval<Container>()))>::type>

T standard_deviation ( Container &&  c )

inline

{
    auto b = std::begin(c), e = std::end(c);
    auto size = std::distance(b, e);
    auto sum = std::accumulate(b, e, T());
    auto mean = sum / size;
 
    if (size == 1)
    {
        return (T) 0;
    }
 
    T accum = T();
    for (const auto d : c)
    {
        accum += (d - mean) * (d - mean);
    }
    return std::sqrt(accum / (size - 1));
}

References mean().

Referenced by WorldSession::ComputeNewClockDelta().