statistics.cxx

#include "statistics.h"
 
#include <iostream>
#include <cmath>
 
namespace cgv {
    namespace utils {
 
statistics::statistics()
{
    init(); 
}
statistics::statistics(const double& v) { init(v); }
statistics::statistics(const double& v, unsigned int n) { init(v,n); }
void statistics::init() { cnt = 0; }
void statistics::init(const double& v) { min = max = sum = v; sms = v*v; cnt = 1; }
void statistics::init(const double& v, unsigned int n) { min = max = v; sum = n*v; sms = n*v*v; cnt = n; }
void statistics::update(const double& v) {
    if (cnt) {
        if (v > max) max = v;
        if (v < min) min = v;
        sum += v;
        sms += v*v;
        ++cnt;
    }
    else
        init(v);
}
void statistics::update(const double& v, unsigned int n) {
    if (cnt) {
        if (v > max) max = v;
        if (v < min) min = v;
        sum += n*v;
        sms += n*v*v;
        cnt += n;
    }
    else
        init(v,n);
}
double statistics::get_average() const { return sum/cnt; }
double statistics::get_variance() const {
    double E = get_average();
    double E2 = sms / cnt;
    return E2 - E*E;
}
double statistics::get_standard_deviation() const {
    return sqrt(get_variance());
}
double statistics::get_sum() const { return sum; }
double statistics::get_sum_of_squares() const { return sms; }
double statistics::get_min() const { return min; }
double statistics::get_max() const { return max; }
unsigned int statistics::get_count() const { return cnt; }
 
std::ostream& operator << (std::ostream& os, const statistics& s)
{
    return os <<  s.get_min() << ".." << s.get_max() 
                 << ":<" << s.get_sum() << "/" << s.get_count() 
                 << "=" << s.get_average() << "+-" << s.get_standard_deviation() << ">";
}
 
    }
}