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Contents
# http://creativecommons.org/publicdomain/zero/1.0/
class RandomGaussian
def initialize(mean, stddev, rand_helper = -> { Kernel.rand })
@rand_helper = rand_helper
@mean = mean
@stddev = stddev
@valid = false
@next = 0
end
def rand
if @valid
@valid = false
@next
else
@valid = true
x, y = self.class.gaussian(@mean, @stddev, @rand_helper)
@next = y
x
end
end
def self.gaussian(mean, stddev, rand)
theta = 2 * Math::PI * rand.call
rho = Math.sqrt(-2 * Math.log(1 - rand.call))
scale = stddev * rho
x = mean + scale * Math.cos(theta)
y = mean + scale * Math.sin(theta)
[x, y]
end
end
Version data entries
37 entries across 37 versions & 1 rubygems