Unbias a random generator: Difference between revisions

=={{header|Elena}}==

{{trans|C#}}

ELENA 3.2.1 :

<lang elena>import extensions.

int extension $op

{

bool randN

= randomGenerator nextInt(self) == 0.

bool unbiased

[

bool flip1 := self randN.

bool flip2 := self randN.

while (flip1 == flip2)

[

flip1 := self randN.

flip2 := self randN.

].

^ flip1

]

}

program =

[

3 to:6 do(&int:n)

[

int biasedZero := 0.

int biasedOne := 0.

int unbiasedZero := 0.

int unbiasedOne := 0.

0 till:100000 do(:i)

[

if (n randN) [ biasedOne += 1 ]; [ biasedZero += 1 ].

if (n unbiased) [ unbiasedOne += 1 ]; [ unbiasedZero += 1 ]

].

console

printLineFormatted("(N = {0}):" padRight(17) + "# of 0"$9"# of 1"$9"% of 0"$9"% of 1", n);

printLineFormatted("Biased:" padRight(15) + "{0}"$9"{1}"$9"{2}"$9"{3}",

biasedZero, biasedOne, biasedZero / 1000, biasedOne / 1000);

printLineFormatted("Unbiased:" padRight(15) + "{0}"$9"{1}"$9"{2}"$9"{3}",

unbiasedZero, unbiasedOne, unbiasedZero / 1000, unbiasedOne / 1000).

]

].</lang>

{{out}}

<pre>

(N = 3): # of 0 # of 1 % of 0 % of 1

Biased: 66793 33207 66 33

Unbiased: 49965 50035 49 50

(N = 4): # of 0 # of 1 % of 0 % of 1

Biased: 75233 24767 75 24

Unbiased: 50106 49894 50 49

(N = 5): # of 0 # of 1 % of 0 % of 1

Biased: 80209 19791 80 19

Unbiased: 50080 49920 50 49

(N = 6): # of 0 # of 1 % of 0 % of 1

Biased: 83349 16651 83 16

Unbiased: 49699 50301 49 50

</pre>