anchor.diff:      
   end subroutine sigmaz_func
   
  +! calculates the horizontal distance from the wake center to the hub of the turbine making
  +! the wake
   subroutine wake_offset_func(rotor_diameter, theta_c_0, x0, yaw, ky, kz, Ct, sigmay, &
                               & sigmaz, wake_offset)
                               
  
positive.code:     
  end subroutine sigmay_func
      
  subroutine sigmaz_func(kz, deltax0, rotor_diameter, sigmaz)
      
      implicit none
  
negative.code: 	theta_c_0 = 0.3_dp * yaw * (1.0_dp - sqrt(1.0_dp - Ct * cos(yaw))) / cos(yaw)
  
  end subroutine theta_c_0_func
  
  ! calculates the horizontal spread of the wake at a given distance from the onset of far 
  ! wake condition
  subroutine sigmay_func(ky, deltax0, rotor_diameter, yaw, sigmay)
      
      implicit none
  