A simple program to benchmark Set.intersectInPlace() in Swift

intersectInPlacePerformance.swift

import Foundation

let smallSet = Set(Array(1..<999).sort {_, _ in arc4random() % 2 == 0})
let largeSet = Set(Array(1..<99999).sort {_, _ in arc4random() % 2 == 0})

var _count = 999999
let unique: () -> Int = { _count += 1; return _count }

var before = NSDate()
var after = NSDate()


var smallLargeDuration: NSTimeInterval = 0
(1...100).forEach { _ in
    var a = smallSet
    var b = largeSet
    a.insert(unique())
    b.insert(unique())

    before = NSDate()
    a.intersectInPlace(b)
    after = NSDate()
    smallLargeDuration += after.timeIntervalSinceDate(before)
}
print("small ∩ large * 100 -- \(smallLargeDuration)")

var largeSmallDuration: NSTimeInterval = 0
(1...100).forEach { _ in
    var b = smallSet
    var a = largeSet
    a.insert(unique())
    b.insert(unique())

    before = NSDate()
    a.intersectInPlace(b)
    after = NSDate()
    largeSmallDuration += after.timeIntervalSinceDate(before)
}
print("large ∩ small * 100 -- \(largeSmallDuration)")

var smallSmallDuration: NSTimeInterval = 0
(1...100).forEach { _ in
    var b = smallSet
    var a = smallSet
    a.insert(unique())
    b.insert(unique())

    before = NSDate()
    a.intersectInPlace(b)
    after = NSDate()
    smallSmallDuration += after.timeIntervalSinceDate(before)
}
print("small ∩ small * 100 -- \(smallSmallDuration)")

var largeLargeDuration: NSTimeInterval = 0
(1...100).forEach { _ in
    var b = largeSet
    var a = largeSet
    a.insert(unique())
    b.insert(unique())

    before = NSDate()
    a.intersectInPlace(b)
    after = NSDate()
    largeLargeDuration += after.timeIntervalSinceDate(before)
}
print("large ∩ large * 100 -- \(largeLargeDuration)")

print("total time spent ----- \(smallLargeDuration + largeSmallDuration + smallSmallDuration + largeLargeDuration)")