hello everyone

please how i can add a function to the differential equation in openfoam, especially the scale function,

like here

: fvm::ddt(T) - (1/(1+dfra(T)*Lat/(CP*eT)))*fvm::laplacian(DT, T) == fvOptions(T)

i can't difinde (dfra(T))

the function what i want add it is this:

int fraction(int n);

using namespace std;

double dfra (double a)

{

double r;

if(a>-0.5 && a<+0.5)

r=1;

else r=0;

return r;

}

Thank you