anchor.diff:     
       
       if ( EqualRealNos(phi, 0.0_ReKi) ) then
  -      fzero =  0.0
  -      a     =  0.0
  -      ap    =  0.0
  +      fzero =  0.0_ReKi
  +      a     =  0.0_ReKi
  +      ap    =  0.0_ReKi
  +      chi   =  0.0_ReKi
         return
       end if
       
  
positive.code: 
     F = Ftip * Fhub
  
        ! bem parameters
     k  = sigma_p*Cx/4.0_DbKi/F/sphi/sphi  ! checked GJH
      
  
negative.code:       yawCorr = (15.0_ReKi*pi/64.0_ReKi*tan(chi/2.0_ReKi) * (r/Rtip) * saz)
        a = a * (1.0 +  yawCorr) ! *(-yawCorr/0.785 + 1) )
          !a = min(a, 0.9)
     !else if ( skewWakeMod == SkewMod_Coupled ) then
     !   chi = (0.6_ReKi*a + 1.0_ReKi)*chi0
     !   a = a * ( 1.0_ReKi + 0.63_ReKi*(r/Rtip)**2 )*(c1 + c2*lambda + c3*lambda**2 + c4*lambda**3 )*( chi*180.0_ReKi/pi )*saz   ! chi needs to be in degrees here.
     end if
     
      ! compute tangential induction factor
  