class CompositeRng

A class of random number generators that work by nesting other PRNGs.

Constants

CHURNS: The limits on the churn limit.
INITS: The limits on the init.
VERSION: The CompositeRng version.

Attributes

churn_limit[R]

The current upper limit on churn

Public Class Methods

new(parent, child, churn_limit=16, init=0) click to toggle source

Create a composite PRNG
Parameters

parent - the starting PRNG
child - the progeny PRNG
churn_limit - the max amount of churning done.
init = the number of initial churn steps.

# File lib/composite_rng.rb, line 21
def initialize(parent, child, churn_limit=16, init=0)
  @parent, @child, @churn_limit = parent, child, churn_limit

  #Validate the churn_limit
  unless CHURNS === @churn_limit
    fail "Invalid churn limit #{@churn_limit}. Allowed values are #{CHURNS}"
  end

  #Validate the init
  unless INITS === init
    fail "Invalid init value #{init}. Allowed values are #{INITS}"
  end

  init.times { churn }
end

Public Instance Methods

churn() click to toggle source

Stir the soup!
Returns

a churned random number generator.

# File lib/composite_rng.rb, line 49
def churn
  (1 + @parent.rand(@churn_limit)).times {@child.rand(256)}
  @child
end

rand(max=0) click to toggle source

An access point for random numbers.
Parameters

max - the range of the numbers to be created.

Returns

a random value generated according to the max parameter.

# File lib/composite_rng.rb, line 42
def rand(max=0)
  churn.rand(max)
end