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package ru.pm.dashboard.helper;
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 import lombok.Getter;
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 import lombok.RequiredArgsConstructor;
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 import java.io.Serializable;
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 import java.util.Comparator;
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 /**
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  * Класс предназначен для расчёта статистических показателей "на лету" без необходимости сохранять значения в списке.
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  */
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 @RequiredArgsConstructor
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 @Getter
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 public class Stats implements Serializable, Comparable<Stats> {
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     private static final long serialVersionUID = 5189576175560182641L;
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     private final String x1;
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     private final String x2;
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     private long mN = 0L;
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     private double mM = 0.0;
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     private double mS = 0.0;
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     private double min = Double.POSITIVE_INFINITY;
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     private double max = Double.NEGATIVE_INFINITY;
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     private double sum = 0.0;
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     /**
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      * Добавить очередное значение из исходных данных
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      *
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      * @param s Значение
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      */
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     public void push(String s) {
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         ++mN;
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         double x;
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         try {
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             x = Double.parseDouble(s);
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         } catch (Exception e) {
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             return;
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         }
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         double nextM = mM + (x - mM) / mN;
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         mS += (x - mM) * (x - nextM);
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         mM = nextM;
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         sum += x;
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         if (x < min) {
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             min = x;
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         }
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         if (x > max) {
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             max = x;
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         }
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     }
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     public long numSamples() {
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         return mN;
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     }
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     public double mean() {
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         return mM;
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     }
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     public double variance() {
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         return mN > 1 ? mS / mN : 0.0;
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     }
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     public double varianceUnbiased() {
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         return mN > 1 ? mS / (mN - 1) : 0.0;
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     }
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     public double standardDeviation() {
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         return Math.sqrt(variance());
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     }
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     public double standardDeviationUnbiased() {
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         return Math.sqrt(varianceUnbiased());
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     }
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     public double min() {
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         return min == Double.POSITIVE_INFINITY ? 0 : min;
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     }
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     public double max() {
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         return max == Double.NEGATIVE_INFINITY ? 0 : max;
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     }
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     public double sum() {
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         return sum;
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     }
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     private static final Comparator<String> NULL_SAFE_STRING_COMPARATOR = Comparator.nullsFirst(String::compareTo);
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     @Override
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     public int compareTo(Stats stats) {
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         return Comparator.comparing(Stats::getX2, NULL_SAFE_STRING_COMPARATOR)
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                 .thenComparing(Stats::getX1)
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                 .compare(this, stats);
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     }
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 }