*! overlapi -- Calculate the overlapping coefficient     (sg27: STB-22)
*! version 1.1.0   14 August 1993  R. Goldstein
program define overlapi
        version 3.0
        confirm number `1'
        confirm number `2'
        confirm number `3'
*       confirm number `4'
    local mean1=min(`1',`2')
    local mean2=max(`1',`2')
if `mean1'==`1' {
    local sd1 `3'
    local sd2 `4'
}
else {
    local sd1 `4'
    local sd2 `3'
    }
    local numb1 `5'
    local numb2 `6'
noi di "MLE of overlap:"
cap confirm number `5'
if _rc==0 {
#del ;
noi di "  Variances equal:   " %6.4f 2*normprob(-(abs(`mean1'-`mean2'))/
      (2*(((`numb1'-1)*`sd1'^2)+(`numb2'-1)*`sd2'^2)/(`numb1'+`numb2'-2)))
    _skip(5) "Dissimilarity Index=1-OVL: "%6.4f 1-2*normprob(-(abs(`mean1'-`mean2'))/
      (2*(((`numb1'-1)*`sd1'^2)+(`numb2'-1)*`sd2'^2)/(`numb1'+`numb2'-2))) ;
#del cr
}
cap confirm number `4'
if _rc!=0 {
#del ;
noi di "  Variances equal:  " %6.4f 2*normprob(-(abs(`mean1'-`mean2'))/
    (2*`sd1')) _skip(5) "Dissimilarity Index=1-OVL: "%6.4f
    1-2*normprob(-(abs(`mean1'-`mean2'))/(2*`sd1')) ;
#del cr
exit
}
#del ;
    local XA=(((`mean1'*(`sd2'^2))-(`mean2'*(`sd1'^2))) + ((`sd1'*`sd2') *
sqrt(((`mean1'-`mean2')^2) +
((`sd2'^2-`sd1'^2)*ln(`sd2'^2/`sd1'^2)))))/(`sd2'^2-`sd1'^2) ;
    local XB=(((`mean1'*(`sd2'^2))-(`mean2'*(`sd1'^2))) - ((`sd1'*`sd2') *
sqrt(((`mean1'-`mean2')^2) +
((`sd2'^2-`sd1'^2)*ln(`sd2'^2/`sd1'^2)))))/(`sd2'^2-`sd1'^2) ;
#del cr
* if min(`XA',`XB')<0 {
    local X1=min(`XA',`XB')
    local X2=max(`XA',`XB')
* }
* else {
*     local X1=max(`XA',`XB')
*     local X2=min(`XA',`XB')
* }
#del ;
local OVL = normprob((`X1'-`mean1')/`sd1') +
    normprob((`X2'-`mean2')/`sd2') - normprob((`X1'-`mean2')/`sd2') -
    normprob((`X2'-`mean1')/`sd1') + 1 ;
#del cr
if `OVL'>1 { local OVL=1-mod(`OVL',1) }
noi di "  Variances UNequal: " %6.4f `OVL' _skip(5) /*
         */ "Dissimilarity Index=1-OVL: "%6.4f 1-`OVL'
end