code 41757;
real procedure ERLANGDENS(X,ALPHA,SCALE);
value X,ALPHA,SCALE; real X,ALPHA,SCALE;
if X < 0
then STATAL3 ERROR(“ERLANGDENS”,1,X) else
if ALPHA ≤ 0 ∨ ENTIER(ALPHA) < ALPHA then
STATAL3 ERROR(“ERLANGDENS”,2,ALPHA) else
if SCALE ≤ 0
then STATAL3 ERROR(“ERLANGDENS”,3,SCALE)
else ERLANGDENS:= if X = 0 then 0 else
EXP(-ALPHA × LN(SCALE) - LOGGAMMA(ALPHA) - X / SCALE +
    (ALPHA - 1) × LN(X));
eop