class EnvelopeAlloc::RandomGaussian

Public Class Methods

gaussian(mean, stddev, rand) click to toggle source
# File lib/envelope_alloc/gaussian.rb, line 4
def self.gaussian(mean, stddev, rand)
  rho = Math.sqrt(-2 * Math.log(1 - rand.call))
  scale = stddev * rho
  theta = 2 * Math::PI * rand.call
  x = mean + scale * Math.cos(theta)
  y = mean + scale * Math.sin(theta)
  [x, y]
end
new(mean, stddev, rand_helper = lambda {Kernel.rand}) click to toggle source
# File lib/envelope_alloc/gaussian.rb, line 13
def initialize(mean, stddev, rand_helper = lambda {Kernel.rand})
  @rand_helper = rand_helper
  @mean = mean
  @stddev = stddev
  @valid = false
  @next = 0
end

Public Instance Methods

rand() click to toggle source
# File lib/envelope_alloc/gaussian.rb, line 21
def rand
  if @valid
    @valid = false
    @next
  else
    @valid = true
    x, y = self.class.gaussian(@mean, @stddev, @rand_helper)
    @next = y
    x
  end
end