A Math-er of fact.md

Code snippets for the blog post "A Math-er of fact"

random-numbers.swift

private func random(_ maxValue: Int) -> Int {
    return Int(arc4random_uniform(UInt32(maxValue)))
}

func uniformRandom(_ range: CountableRange<Int>) -> Int {
    return range.startIndex + random(range.endIndex - range.startIndex)
}

func skewedRandom(_ range: CountableRange<Int>) -> Int {
    let x = random(range.endIndex - range.startIndex)
    return range.startIndex + Int(Double(range.endIndex) * atan(Double(x))/M_PI_2)
}

test.swift

let sampleSize = 30
let range = 0 ..< 10

var numbers = Array(0 ..< sampleSize).map({ _ in uniformRandom(range) }).sorted()
print("uniform distribution \(numbers)")

numbers = Array(0 ..< sampleSize).map({ _ in skewedRandom(range) }).sorted()
print("skewed distribution  \(numbers)")