cap pro drop sortedf1
pro def sortedf1

args v
qui sum `v'
local vN=r(N)

tempvar univ diff                     /*initialize univ and diff, can be any other finite value*/
gen `univ'=`v'
gen `diff'=1

sortuniq1 `univ'                      /* sort v and keep only the unique values*/

qui sum `univ'
local uN=r(N)

local i=1

while `i'<= `vN'{                     /* from this line to the end: generate the sorted data density*/
  local j=`i'
      while `j' >= 1 { 
           if `v'[`i']==`univ'[`j']{
                continue, break
           }
           else{  
                local j=`j'-1 
           }
      }
      if  `j' == 1{  
      qui replace `diff'=`univ'[2]-`univ'[1] in `i'
      }     
      else if  `j'==`uN'{    
      qui replace `diff'=`univ'[`uN']-`univ'[`uN'-1] in `i'
      }
      else{
      qui replace `diff'=`univ'[`j'+1]-`univ'[`j'-1] in `i'
      }
  local i=`i' + 1
}

*list `diff'

replace `v'=2/(_N*`diff')

*list `v'
end