statistics::stats_computer1< T > Class Template Reference

Public Member Functions
void	new_val (T x)
double	mean () const
double	variance () const
double	std () const

Private Attributes
unsigned int	n = 0
double	Ex
double	Ex2
T	K

Friends
std::istream &	operator>> (std::istream &input, stats_computer1 &stat)

Detailed Description

template<typename T>
class statistics::stats_computer1< T >

continuous mean and variance computance using first value as an approximation for the mean. If the first number is much far form the mean, the algorithm becomes very inaccurate to compute variance and standard deviation.

Member Function Documentation

mean()

template<typename T >

double statistics::stats_computer1< T >::mean ( ) const

inline

return sample mean computed till last sample

{ return K + Ex / n; }

new_val()

template<typename T >

void statistics::stats_computer1< T >::new_val ( T  x )

inline

Constructor

Parameters

[in]

x

new data sample

                      {
        if (n == 0)
            K = x;
        n++;
        T tmp = x - K;
        Ex += tmp;
        Ex2 += static_cast<double>(tmp) * tmp;
    }

std()

template<typename T >

double statistics::stats_computer1< T >::std ( ) const

inline

return sample standard deviation computed till last sample

{ return std::sqrt(this->variance()); }

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variance()

template<typename T >

double statistics::stats_computer1< T >::variance ( ) const

inline

return data variance computed till last sample

{ return (Ex2 - (Ex * Ex) / n) / (n - 1); }

Friends And Related Function Documentation

operator>>

template<typename T >

std::istream & operator>> ( std::istream &  input, stats_computer1< T > &  stat  )

friend

short-hand operator to read new sample from input stream
e.g.: std::cin >> stats1;

                                                           {
        T val;
        input >> val;
        stat.new_val(val);
        return input;
    }

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The documentation for this class was generated from the following file:

• math/realtime_stats.cpp