Class: RandomBell

Inherits:
Object
  • Object
show all
Defined in:
lib/random_bell.rb,
lib/random_bell/version.rb

Constant Summary collapse

VERSION = 
"0.2.0"

Instance Method Summary collapse

Constructor Details

#initialize(mu: 0.5, sigma: 0.2, range: 0.0..1.0, seed: Random.new_seed, method: :box_muller) ⇒ RandomBell

Returns a new instance of RandomBell.

Parameters:

  • mu (Float) (defaults to: 0.5)
  • sigma (Float) (defaults to: 0.2)
  • range (Range) (defaults to: 0.0..1.0)
  • seed (Integer) (defaults to: Random.new_seed)
  • method (Symbol) (defaults to: :box_muller) —

    Method to generate standard normal distribution (:box_muller or :central_limit)



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# File 'lib/random_bell.rb', line 9

def initialize(mu: 0.5, sigma: 0.2, range: 0.0..1.0, seed: Random.new_seed, method: :box_muller)
  @mu     = mu
  @sigma  = sigma
  @range  = range
  @rand_generator = Random.new(seed)
  @method = method
end

Instance Method Details

#normal ⇒ Float

Returns:

  • (Float) 


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# File 'lib/random_bell.rb', line 23

def normal
  @mu + standard * @sigma
end

#rand ⇒ Float

Returns:

  • (Float) 


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# File 'lib/random_bell.rb', line 28

def rand
  loop do
    num = normal
    return num if @range.include?(num)
  end
end

#standard ⇒ Float

Returns:

  • (Float) 


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# File 'lib/random_bell.rb', line 18

def standard
  send(@method)
end

#to_histogram(rows: 20, size: 10 ** 4) ⇒ String

Returns:

  • (String) 


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# File 'lib/random_bell.rb', line 36

def to_histogram(rows: 20, size: 10 ** 4)
  histogram = ""

  numbers = (1..size).to_a.map{ rand }

  klasses, klass_width = [], (@range.max - @range.min).to_f / rows
  (0..rows).each_cons(2) do |left, right|
    klasses << Range.new(@range.min + klass_width * left, @range.min + klass_width * right)
  end

  divider = (klasses.map{|klass| numbers.select{|num| klass.include?(num) }.size }.max / 50.0).ceil
  klasses.each do |klass|
    n = numbers.select{|num| klass.include?(num) }.size / divider
    histogram << sprintf("%+3.3f", klass.max) << ": " << "*" * n << "\n"
  end

  histogram
end