code 41564; real procedure ERLANGINV(PROB,ALPHA,SCALE); value PROB,ALPHA,SCALE; real PROB,ALPHA,SCALE; if PROB ≤ 10-10 ∨ PROB ≥ 1 - 10-10 then STATAL3 ERROR(“ERLANGINV”,1,PROB) else if ALPHA ≤ 0 ∨ ENTIER(ALPHA) < ALPHA then STATAL3 ERROR(“ERLANGINV”,2,ALPHA) else if SCALE ≤ 0 then STATAL3 ERROR(“ERLANGINV”,3,SCALE) else ERLANGINV:= GAMMAINV(PROB,ALPHA, SCALE); eop