Numeric::relativeDifference exact, w/o epsilon

Base/Math/Numeric.cpp

@@ -27,12 +27,7 @@ void check_scalar(double a, double b, int ulp)
 
 double Numeric::relativeDifference(double a, double b)
 {
-    constexpr double eps = std::numeric_limits<double>::epsilon();
-    const double avg_abs = (std::abs(a) + std::abs(b)) / 2.0;
-    // return 0.0 if relative error smaller than epsilon
-    if (std::abs(a - b) <= eps * avg_abs)
-        return 0.0;
-    return std::abs(a - b) / avg_abs;
+    return 2 * std::abs(a - b) / (std::abs(a) + std::abs(b));
 }
 
 bool Numeric::almostEqual(double a, double b, int ulp)