math Functions: replace float with T

src/lib/mathlib/math/Functions.hpp

@@ -146,8 +146,8 @@ const T gradual(const T &value, const T &x_low, const T &x_high, const T &y_low,
 
 	} else {
 		/* linear function between the two points */
-		float a = (y_high - y_low) / (x_high - x_low);
-		float b = y_low - a * x_low;
+		T a = (y_high - y_low) / (x_high - x_low);
+		T b = y_low - a * x_low;
 		return  a * value + b;
 	}
 }