This function is the 2nd order derivative of BuildingSystems.Utilities.Math.Functions.BaseClasses.smoothTransition.
For efficiency, the polynomial coefficients
a, b, c, d, e, f
and
the inverse of the smoothing parameter deltaInv
are exposed as arguments to this function.
function der_2_smoothTransition extends Modelica.Icons.Function; input Real x "Abscissa value"; input Real delta(min = Modelica.Constants.eps) "Abscissa value below which approximation occurs"; input Real deltaInv "Inverse value of delta"; input Real a "Polynomial coefficient"; input Real b "Polynomial coefficient"; input Real c "Polynomial coefficient"; input Real d "Polynomial coefficient"; input Real e "Polynomial coefficient"; input Real f "Polynomial coefficient"; input Real x_der "Derivative of x"; input Real x_der2 "Second order derivative of x"; output Real y_der2 "Second order derivative of function value"; end der_2_smoothTransition;