Probabilistic choice: Difference between revisions

</pre>

=={{header|Wren}}==

{{trans|Kotlin}}

{{libheader|Wren-fmt}}

<lang ecmascript>import "random" for Random

import "/fmt" for Fmt

var letters = ["aleph", "beth", "gimel", "daleth", "he", "waw", "zayin", "heth"]

var actual = [0] * 8

var probs = [1/5, 1/6, 1/7, 1/8, 1/9, 1/10, 1/11, 0]

var cumProbs = [0] * 8

cumProbs[0] = probs[0]

for (i in 1..6) cumProbs[i] = cumProbs[i-1] + probs[i]

cumProbs[7] = 1

probs[7] = 1 - cumProbs[6]

var n = 1e6

var rand = Random.new()

(1..n).each { |i|

var r = rand.float()

var index = (r <= cumProbs[0]) ? 0 :

(r <= cumProbs[1]) ? 1 :

(r <= cumProbs[2]) ? 2 :

(r <= cumProbs[3]) ? 3 :

(r <= cumProbs[4]) ? 4 :

(r <= cumProbs[5]) ? 5 :

(r <= cumProbs[6]) ? 6 : 7

actual[index] = actual[index] + 1

}

var sumActual = 0

System.print("Letter\t Actual Expected")

System.print("------\t-------- --------")

for (i in 0..7) {

var generated = actual[i]/n

Fmt.print("$s\t$8.6f $8.6f", letters[i], generated, probs[i])

sumActual = sumActual + generated

}

System.print("\t-------- --------")

Fmt.print("\t$8.6f 1.000000", sumActual)</lang>

{{out}}

Sample run:

<pre>

Letter Actual Expected

------ -------- --------

aleph 0.200037 0.200000

beth 0.166643 0.166667

gimel 0.143012 0.142857

daleth 0.125219 0.125000

he 0.111183 0.111111

waw 0.099510 0.100000

zayin 0.091015 0.090909

heth 0.063381 0.063456

-------- --------

1.000000 1.000000