use "D:\计量经济学\计量Work\劳动力市场分割\slm.dta", clear

. do "C:\Documents and Settings\Administrator\桌面\switch.do"

.
. program define switch
  1. args lnf W P S sig13 sig11 sig23 sig22
  2. quietly replace `lnf'=(1-norm((-`W'-(`sig13'/`sig11')*($ML_y1-`P'))/((1-(`sig13'^2/`sig11'))^.5)))
  3. *dnorm(($ML_y1-`P')/`sig11'^.5)*(1/`sig11'^.5)+(norm((-`W'-(`sig23'/`sig22')*($ML_y2-`S'))/((1-(`sig23'
> ^2/`sig22'))^.5))
. *dnorm(($ML_y2-`S')/`sig22'^.5)*(1/`sig22'^.5))
. quietly replace `lnf'=ln(`lnf')
  4. end

.
end of do-file

. ml model lf switch (sep:  Guesprob  urban gender educ pdummy) (sa0:  lipyear  expe expe2 gender folk ed
> uc party)(sa1:  lipyear  expe expe2 gender folk educ party)

. ml max

Unknown function norm()
r(133);

. ml max,difficult

Unknown function norm()
r(133);