std_dev_calc.h

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#pragma once
 
#include <windows.h>
#include <iostream>
#include <map>
 
namespace pesieve {
    namespace stats {
 
        class StdDeviationCalc
        {
        public:
            StdDeviationCalc(const std::map<BYTE, size_t>& _population, size_t _max)
                : mean(0), population(_population)
            {
                max = _max;
                mean = calcMean();
            }
 
            double getSum() { return sum; }
 
            double getMean() { return mean; }
 
            double calcSampleVariance()
            {
                if (max == 0) return 0;
                return _calcVariance(max - 1);
            }
 
            double calcPopulationVariance()
            {
                return _calcVariance(max);
            }
            
            double calcSampleStandardDeviation()
            {
                return sqrt(calcSampleVariance());
            }
 
            double calcPopulationStandardDeviation()
            {
                return sqrt(calcPopulationVariance());
            }
            
            void printAll()
            {
                std::cout << "Counts Sum:\t\t\t: " << calcSum() << "\n";
                std::cout << "Total Numbers\t\t\t: " << max << "\n";
                std::cout << "Mean\t\t\t\t: " << mean << "\n";
                std::cout << "Population Variance\t\t: " << calcPopulationVariance() << "\n";
                std::cout << "Sample variance\t\t\t: " << calcSampleVariance() << "\n";
                std::cout << "Population Standard Deviation\t: " << calcPopulationStandardDeviation() << "\n";
                std::cout << "Sample Standard Deviation\t: " << calcSampleStandardDeviation() << "\n";
            }
 
        private:
 
            double _calcVariance(ULONG _max)
            {
                if (_max == 0) return 0;
 
                double temp = 0;
                for (auto itr = population.begin(); itr != population.end(); ++itr)
                {
                    const double val = itr->second;
                    temp += (val - mean) * (val - mean);
                }
                return temp / _max;
            }
 
            double calcSum()
            {
                double sum = 0;
                for (auto itr = population.begin(); itr != population.end(); ++itr) {
                    const double val = itr->second;
                    sum += val;
                }
                return sum;
            }
 
            double calcMean()
            {
                if (max == 0) return 0;
 
                double sum = calcSum();
                return (sum / max);
            }
 
            size_t max;
            const std::map<BYTE, size_t>& population;
            double mean;
            double sum;
 
        }; // namespace stats
    }; // namespace pesieve
};