Random numbers: Difference between revisions

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<lang scala>List.fill(1000)(1.0 + 0.5 * scala.util.Random.nextGaussian)</lang>

===Academic===

<lang scala>~~val distrubution = {~~

object RandomNumbers extends App {

def randomNormal = 1.0 + 0.5 * scala.util.Random.nextGaussian

val distribution: LazyList[Double] = {

def normalDistribution(a: Double): Stream[Double] = a #:: normalDistribution(randomNormal)

def randomNormal: Double = 1.0 + 0.5 * scala.util.Random.nextGaussian

normalDistribution(randomNormal)

def normalDistribution(a: Double): LazyList[Double] = a #:: normalDistribution(randomNormal)

}

normalDistribution(randomNormal)

/*

}

* Let's test it

*/

/*

* Let's test it

*/

def calcAvgAndStddev[T](ts: Iterable[T])(implicit num: Fractional[T]): (T, Double) = {

val mean: T =

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// Root of mean diffs

val stdDev = sqrt(ts.map { x =>

val stdDev = Math.sqrt(ts.map { x =>

val diff = num.toDouble(num.minus(x, mean))

diff * diff

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}

println(calcAvgAndStddev(~~distrubution~~.take(1000))) // e.g. (1.0061433267806525,0.5291834867560893)~~</lang>~~

println(calcAvgAndStddev(distribution.take(1000))) // e.g. (1.0061433267806525,0.5291834867560893)

}

</lang>

=={{header|Scheme}}==