pro def polych_ll
   version 8.1

   args lf rho

   #delimit ;
   qui replace __POLYpi =
                   binorm(__POLY1hi,__POLY2hi,`rho') -
                   binorm(__POLY1lo,__POLY2hi,`rho') -
                   binorm(__POLY1hi,__POLY2lo,`rho') +
                   binorm(__POLY1lo,__POLY2lo,`rho')
   ;
   #delimit cr
   qui replace `lf' = ln( __POLYpi )

end