*! version 1.0 13/09/98  (STB-53: sg128)
program define bhatgauc
version 5.0
*Author: Isaias H. Salgado Ugarte
*First written (version 5.0) 13/09/98
*Last review: 13/09/98
local varlist "req ex min(2) max(2)"
local if "opt"
local in "opt"
#delimit ;
local options "Gen(string) noGraph T1title(string) Symbol(string) 
      Connect(string) *";
#delimit cr
parse "`*'"
parse "`varlist'", parse(" ")
quietly {
 tempvar logfreq laglog diflog
 gen `logfreq'=log(`1')
 gen `laglog'=`logfreq'[_n+1]
 gen `diflog'=`laglog'-`logfreq'

         tempvar touse
         gen byte `touse'=0
         replace `touse'=1 `in'
         regress `diflog' `2' if `touse'
         tempvar width mean sd b gauprob sumgaup sumsmfr en gaucom
         gen `width'=`2'[2]-`2'[1]
         gen `mean'=-1*_b[_cons]/_b[`2']+`width'/2
         gen `sd'=sqrt(`width'/(-1*_b[`2']))
         }
 gen `b'=_b[`2']
 if `b'>0 {
    di "The slope of selected points is >0" 
    exit}
 else 
 di "R-squared = " %5.4f _result(7) _skip(10) "Adj R-squared = " %5.4f _result(8) 
 di "Mean = " %5.4f `mean'
 di "s.d. = " %5.4f `sd'
 quietly {
 gen `gauprob'=`width'*(1/(`sd'*sqrt(2*_pi)))*exp(-.5*((`2'-`mean')/`sd')^2)
 egen `sumgaup'=sum(`gauprob') if `touse'
 egen `sumsmfr'=sum(`1') if `touse'
 gen `en'=`sumsmfr'[2]/`sumgaup'[2]
 replace `en'=round(`en',1)
 noisily di "component size = " `en'
 gen `gaucom'=`en'*`gauprob'
 sort `2'
 }

    if "`graph'" ~= "nograph"  {
       if "`t1title'" ==""{
          local t1title "Gaussian component"
           }
       if "`symbol'"=="" { local symbol "op" }
       if "`connect'"=="" { local connect "ls" }
       graph `1' `gaucom' `2', `options' /*
				*/ t1("`t1title'") /*
				*/ s(`symbol') c(`connect')
   } 
    if "`gen'"~="" {
       rename `gaucom' `gen'
       }

end