Functions and CALL Routines 
Category:  Random Number 
Tip:  If you want to change the seed value during execution, you must use the CALL RANEXP routine instead of the RANEXP function. 
Syntax  
Arguments  
Details  
Comparisons  
See Also 
Syntax 
RANEXP(seed) 
is a numeric constant, variable, or expression with an integer value. If seed 0, the time of day is used to initialize the seed stream.
Range:  seed < 2^{31}1 
See:  Seed Values for more information about seed values 
Details 
The RANEXP function returns a variate that is generated from an exponential distribution with parameter 1. An inverse transform method applied to a RANUNI uniform variate is used.
An exponential variate X with parameter LAMBDA can be generated:
x=ranexp(seed)/lambda;
An extreme value variate X with location parameter ALPHA and scale parameter BETA can be generated:
x=alphabeta*log(ranexp(seed));
A geometric variate X with parameter P can be generated as follows:
x=floor(ranexp(seed)/log(1p));
For a discussion about seeds and streams of data, as well as examples of using the randomnumber functions, see Generating Multiple Variables from One Seed in RandomNumber Functions.
Comparisons 
The CALL RANEXP routine, an alternative to the RANEXP function, gives greater control of the seed and random number streams.
See Also 

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