CFD Online Discussion Forums - RANS - Calculate k&epsilon if there are not present

Hello,

I try to write an unverisal function for an challange and has no idea for the universal part.
If in the RANS simulation is
k := turbulent kinetic energy
or/and
epsilon := energy dissipation rate
are not present (e.g. k-omega turb. model), how can I calculate the values/fields. The formula are present (k, epsilon)

Please tell me an way to calculate the values in a function that are written to system/controlDict

Code:

...

functions

{

    calcSomething

    {

        libs        ("libutilityFunctionObjects.so");

        type coded;

        name abc;

        codeWrite

        #{

            // if epsilon is not present

               // do calc

            // if k is not present

               // do calc

            // ...

        #};

    }

}