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Functions and CALL Routines

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.

See Also


RANTBL(seed,p1 ,... pi... ,pn)



is a numeric constant, variable, or expression with an integer value. If seed [le] 0, the time of day is used to initialize the seed stream.

Range: seed < 231-1
See: Seed Values for more information about seed values

is a numeric constant, variable, or expression.

Range: 0 [le] pi [le] 1 for 0 <i [le] n


The RANTBL function returns a variate that is generated from the probability mass function defined by p1 through pn . An inverse transform method applied to a RANUNI uniform variate is used. RANTBL returns


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

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.

For a discussion and example of an effective use of the random number CALL routines, see Starting, Stopping, and Restarting a Stream.


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

See Also

Functions and CALL routines:

RAND Function


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