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# simulation::random(n) 0.1 tcllib "Tcl Simulation Tools"

## Name

simulation::random - Pseudo-random number generators

## Synopsis

- package require Tcl ?8.4?
- package require simulation::random 0.1

- ::simulation::random::prng_Bernoulli p
- ::simulation::random::prng_Discrete n
- ::simulation::random::prng_Poisson lambda
- ::simulation::random::prng_Uniform min max
- ::simulation::random::prng_Exponential min mean
- ::simulation::random::prng_Normal mean stdev
- ::simulation::random::prng_Pareto min steep
- ::simulation::random::prng_Gumbel min f
- ::simulation::random::prng_chiSquared df
- ::simulation::random::prng_Disk rad
- ::simulation::random::prng_Sphere rad
- ::simulation::random::prng_Ball rad
- ::simulation::random::prng_Rectangle length width
- ::simulation::random::prng_Block length width depth

## Description

This package consists of commands to generate pseudo-random number generators. These new commands deliver

- numbers that are distributed normally, uniformly, according to a Pareto or Gumbel distribution and so on

- coordinates of points uniformly spread inside a sphere or a rectangle

For example:

        set p [::simulation::random::prng_Normal -1.0 10.0]

produces a new command (whose name is stored in the variable "p") that generates normally distributed numbers with a mean of -1.0 and a standard deviation of 10.0.

## PROCEDURES

The package defines the following public procedures for discrete distributions:

::simulation::random::prng_Bernoulli p

  Create a command (PRNG) that generates numbers with a Bernoulli distribution: the value is either 1 or 0, with a chance p to be 1

  float p

    Chance the outcome is 1

::simulation::random::prng_Discrete n

  Create a command (PRNG) that generates numbers 0 to n-1 with equal probability.

  int n

    Number of different values (ranging from 0 to n-1)

::simulation::random::prng_Poisson lambda

  Create a command (PRNG) that generates numbers according to the Poisson distribution.

  float lambda

    Mean number per time interval

The package defines the following public procedures for continuous distributions:

::simulation::random::prng_Uniform min max

  Create a command (PRNG) that generates uniformly distributed numbers between "min" and "max".

  float min

    Minimum number that will be generated

  float max

    Maximum number that will be generated

::simulation::random::prng_Exponential min mean

  Create a command (PRNG) that generates exponentially distributed numbers with a given minimum value and a given mean value.

  float min

    Minimum number that will be generated

  float mean

    Mean value for the numbers

::simulation::random::prng_Normal mean stdev

  Create a command (PRNG) that generates normally distributed numbers with a given mean value and a given standard deviation.

  float mean

    Mean value for the numbers

  float stdev

    Standard deviation

::simulation::random::prng_Pareto min steep

  Create a command (PRNG) that generates numbers distributed according to Pareto with a given minimum value and a given distribution steepness.

  float min

    Minimum number that will be generated

  float steep

    Steepness of the distribution

::simulation::random::prng_Gumbel min f

  Create a command (PRNG) that generates numbers distributed according to Gumbel with a given minimum value and a given scale factor. The probability density function is:

           P(v) = exp( -exp(f*(v-min)))

  float min

    Minimum number that will be generated

  float f

    Scale factor for the values

::simulation::random::prng_chiSquared df

  Create a command (PRNG) that generates numbers distributed according to the chi-squared distribution with df degrees of freedom. The mean is 0 and the standard deviation is 1.

  float df

    Degrees of freedom

The package defines the following public procedures for random point sets:

::simulation::random::prng_Disk rad

  Create a command (PRNG) that generates (x,y)-coordinates for points uniformly spread over a disk of given radius.

  float rad

    Radius of the disk

::simulation::random::prng_Sphere rad

  Create a command (PRNG) that generates (x,y,z)-coordinates for points uniformly spread over the surface of a sphere of given radius.

  float rad

    Radius of the disk

::simulation::random::prng_Ball rad

  Create a command (PRNG) that generates (x,y,z)-coordinates for points uniformly spread within a ball of given radius.

  float rad

    Radius of the ball

::simulation::random::prng_Rectangle length width

  Create a command (PRNG) that generates (x,y)-coordinates for points uniformly spread over a rectangle.

  float length

    Length of the rectangle (x-direction)

  float width

    Width of the rectangle (y-direction)

::simulation::random::prng_Block length width depth

  Create a command (PRNG) that generates (x,y,z)-coordinates for points uniformly spread over a block

  float length

    Length of the block (x-direction)

  float width

    Width of the block (y-direction)

  float depth

    Depth of the block (z-direction)

## Keywords

math, random numbers, simulation, statistical distribution

## Category

Mathematics

## Copyright

Copyright © 2004 Arjen Markus <arjenmarkus@users.sourceforge.net>