Unbias a random generator: Difference between revisions

=={{header|Ruby}}==

<lang ruby>def rand_n(bias)

rand(bias) <=> 0

end

def unbiased(bias)

a, b = rand_n(bias), rand_n(bias) until a != b

a

end

runs = 1_000_000

keys = %i(bias biased unbiased) #use [:bias,:biased,:unbiased] in Ruby < 2.0

puts keys.join("\t")

(3..6).each do |bias|

counter = Hash.new(0)

runs.times do

counter[:biased] += 1 if rand_n(bias) == 1

counter[:unbiased] += 1 if unbiased(bias) == 1

end

counter[:bias] = bias

puts counter.values_at(*keys).join("\t")

end</lang>

{{output}}

<pre>

bias biased unbiased

3 666180 499845

4 749748 499773

5 799898 500192

6 833180 500740

</pre>