25.6 Commands at a glance
Following is a list of mathematical support related commands commonly used
in simulation scripts:
set rng [new RNG]
This creates a new random number generator.
$rng seed 0 or n
This command seeds the RNG. If 0 is specified, the RNG is seeded
heuristically. Otherwise the RNG is seeded with the value <n>.
$rng next-random
This returns the next random number from RNG.
$rng uniform a b
This returns a number uniformly distributed on <a> and <b>.
$rng integer k
This returns an integer uniformly distributed on 0 and k-1.
$rng exponential
This returns a number that has exponential distribution with average 1.
set rv [new Randomvariable/type of random-variable]
This creates an instance of a random variable object that generates random
variables with specific distribution. The different types of random
variables derived from the base class are:
RandomVariable/Uniform, RandomVariable/Exponential, RandomVariable/Pareto,
RandomVariable/Constant, RandomVariable/HyperExponential.
Each of these distribution types are parameterized with values of
appropriate parameters. For details see section
25.2 of this
chapter.
$rv use-rng rng
This method is used to associated a random variable object with a
non-default RNG. Otherwise by default, the random variable object is
associated with the default random number generator.
Tom Henderson
2011-11-05