module FUNCTION_TEST
use MY_STUFF
contains

   function f(koord)
   implicit none
                                                                                
          real(KIND=dbl), intent(in) :: koord(2) 
          real(KIND=dbl) :: f

   f = 10.0*(koord(1) - 1.0)**(2.0) + 20.0*(koord(2) - 2.0)**2
   end function f

end module FUNCTION_TEST