CorrelationCoefficient: Separate class

common/CorrelationCoefficient.cpp

@@ -0,0 +1,33 @@
+//
+// Created by leonarski_f on 18.05.2026.
+//
+
+#include <cmath>
+
+#include "CorrelationCoefficient.h"
+
+void CorrelationCoefficient::Add(double x, double y) {
+        sum_x += x;
+        sum_y += y;
+        sum_x2 += x * x;
+        sum_y2 += y * y;
+        sum_xy += x * y;
+        n_cc++;
+}
+
+double CorrelationCoefficient::GetCC() const {
+         if (n_cc < 2)
+            return NAN;
+        const double n = static_cast<double>(n_cc);
+        const double mean_x = sum_x / n;
+        const double mean_y = sum_y / n;
+
+        const double cov = sum_xy / n - mean_x * mean_y;
+        const double var_x = sum_x2 / n - mean_x * mean_x;
+        const double var_y = sum_y2 / n - mean_y * mean_y;
+
+        if (!(var_x > 0.0 && var_y > 0.0))
+            return NAN;
+
+        return cov / std::sqrt(var_x * var_y);
+}