RANTBL Function

Returns a random variate from a tabled probability distribution

Category: Random Number

Tip: If you want to change the seed value during execution, you must use the CALL RANTBL routine instead of the RANTBL function.

Syntax

RANTBL ( seed,p 1, p _i , p _n )

Arguments

seed

• is an integer. If seed ‰ 0, the time of day is used to initialize the seed stream.

• Range: seed < 2 ³¹ -1

• See: 'Seed Values' on page 257 for more information about seed values

p _i

• is a numeric SAS value.

• Range: ‰ p _i ‰ 1 for 0 < i ‰ n

Details

The RANTBL function returns a variate that is generated from the probability mass function defined by p ₁ through p _n . An inverse transform method applied to a RANUNI uniform variate is used. RANTBL returns

If, for some index j < n , , RANTBL returns only the indices 1 through j with the probability of occurrence of the index j equal to .

Let n=3 and P1, P2, and P3 be three probabilities with P1+P2+P3=1, and M1, M2, and M3 be three variables . The variable X in these statements

 array m{3} m1-m3;  x=m{rantbl(seed,of p1-p3)}; 

will be assigned one of the values of M1, M2, or M3 with probabilities of occurrence P1, P2, and P3, respectively.

Comparisons

The CALL RANTBL routine, an alternative to the RANTBL function, gives greater control of the seed and random number streams.

See Also

Call routine:

'CALL RANTBL Routine' on page 379