function ssoPhase, param, phase, G12=G12, LCI=LCI
  COMPILE_OPT hidden, idl2
;-----------------------------------------------------------------------------------------------;
;-----------------------------------------------------------------------------------------------;
;---  TAG ---    I -- Initialization And Input Verification              -----------------------;
;-----------------------------------------------------------------------------------------------;
;-----------------------------------------------------------------------------------------------;

 ;--I.1-- Input Syntax Verification  ----------------------------------------------------



;-----------------------------------------------------------------------------------------------;
;-----------------------------------------------------------------------------------------------;
;---  TAG ---    I -- Initialization And Input Verification              -----------------------;
;-----------------------------------------------------------------------------------------------;
;-----------------------------------------------------------------------------------------------;
 ;--- H G

;-----------------------------------------------------------------------------------------------;
;-----------------------------------------------------------------------------------------------;
;---  TAG ---    I -- Initialization And Input Verification              -----------------------;
;-----------------------------------------------------------------------------------------------;
;-----------------------------------------------------------------------------------------------;
  if keyword_set(LCI) then begin
    mag = param.A * exp( -phase/param.D ) + phase*param.k + 1
  endif

;-----------------------------------------------------------------------------------------------;
;-----------------------------------------------------------------------------------------------;
;---  TAG ---   IV -- IAU G12 Standard  - Muinonen et al. 2010           -----------------------;
;-----------------------------------------------------------------------------------------------;
;-----------------------------------------------------------------------------------------------;
  if keyword_set(G12) then begin

    phi1 = 1. - 6*phase*!DTOR/!PI
    phi2 = 1. - 9*phase*!DTOR/(5*!PI)
    phi3 = exp( -4*!PI*tan(phase*!DTOR/2.)^(2./3.) )

    G1 =  0.9529 * param.g12 + 0.02162
    G2 = -0.6125 * param.g12 + 0.55722

    mag = phi1*G1 + G2*phi2 + (1-G1-G2)*phi3 

  endif





  return, mag

end